Artigos de revistas: "Ca(2+)-calmodulin dependent protein kinase"

1

Lee, J. C., e A. M. Edelman. "A protein activator of Ca(2+)-calmodulin-dependent protein kinase Ia." Journal of Biological Chemistry 269, n.º 3 (janeiro de 1994): 2158–64. http://dx.doi.org/10.1016/s0021-9258(17)42149-1.

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Mayer, P., M. Möhlig, U. Seidler, H. Rochlitz, M. Fährmann, H. Schatz, H. Hidaka e A. Pfeiffer. "Characterization of γ- and δ-subunits of Ca2+/calmodulin-dependent protein kinase II in rat gastric mucosal cell populations". Biochemical Journal 297, n.º 1 (1 de janeiro de 1994): 157–62. http://dx.doi.org/10.1042/bj2970157.

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We searched for the occurrence of a Ca2+/calmodulin-dependent protein kinase in rat gastric cell types as a likely member in the chain of gastrin- and muscarinic-receptor-mediated signal transmission. A Ca(2+)- and calmodulin-dependent phosphorylation of major 50, 60 and 100 kDa substrates was observed in parietal cell cytosol and a major 60 and 61 kDa protein doublet was found to bind 125I-calmodulin in 125I-calmodulin-gel overlays. A specific substrate of the multifunctional Ca2+/calmodulin-dependent protein kinase II, autocamtide II, was phosphorylated in a calmodulin-dependent manner. The specific inhibitor of this enzyme, KN-62, antagonized protein kinase activity. RNA extracted from gastric mucosal cells was shown to contain sequences of the gamma- and delta- but not alpha- and beta-subunits of the calmodulin-dependent kinase II, and mRNA of both subtypes was demonstrated in highly purified parietal, chief and mucous cells. A calmodulin-dependent kinase II composed of gamma- and delta-subunits is a likely mediator of Ca(2+)-dependent signal transmission in these populations of gastric cells.

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Chenglong, Liu, Liu Haihua, Zhang Fei, Zheng Jie e Wei Fang. "Scutellarin Mitigates Cancer-Induced Bone Pain by Suppressing CaMKII/CREB Pathway in Rat Models". Current Topics in Nutraceutical Research 17, n.º 3 (1 de abril de 2019): 249–53. http://dx.doi.org/10.37290/ctnr2641-452x.17:249-253.

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Cancer-induced bone pain is a severe and complex pain caused by metastases to bone in cancer patients. The aim of this study was to investigate the analgesic effect of scutellarin on cancer-induced bone pain in rat models by intrathecal injection of Walker 256 carcinoma cells. Mechanical allodynia was determined by paw withdrawal threshold in response to mechanical stimulus, and thermal hyperalgesia was indicated by paw withdrawal latency in response to noxious thermal stimulus. The paw withdrawal threshold and paw withdrawal latencies were significantly decreased after inoculation of tumor cells, whereas administration of scutellarin significantly attenuated tumor cell inoculation-induced mechanical and heat hyperalgesia. Tumor cell inoculation-induced tumor growth was also significantly abrogated by scutellarin. Ca²⁺/calmodulin-dependent protein kinase II is a multifunctional kinase with up-regulated activity in bone pain models. The activation of Ca²⁺/calmodulin-dependent protein kinase II triggers phosphorylation of cAMP-response element binding protein. Scutellarin significantly reduced the expression of phosphorylated-Ca²⁺/calmodulin-dependent protein kinase II and phosphorylated-cAMP-response element binding protein in cancer-induced bone pain rats. Collectively, our study demonstrated that scutellarin attenuated tumor cell inoculation-induced bone pain by down-regulating the expression of phosphorylated-Ca²⁺/calmodulin-dependent protein kinase II and phosphorylated-cAMP-response element binding protein. The suppressive effect of scutellarin on phosphorylated-Ca²⁺/calmodulin-dependent protein kinase II/phosphorylated-cAMP-response element binding protein activation may serve as a novel therapeutic strategy for CIBP management.

4

Purohit, Anil, Adam G. Rokita, Xiaoqun Guan, Biyi Chen, Olha M. Koval, Niels Voigt, Stefan Neef et al. "Oxidized Ca 2+ /Calmodulin-Dependent Protein Kinase II Triggers Atrial Fibrillation". Circulation 128, n.º 16 (15 de outubro de 2013): 1748–57. http://dx.doi.org/10.1161/circulationaha.113.003313.

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5

Yuan, W., e D. M. Bers. "Ca-dependent facilitation of cardiac Ca current is due to Ca-calmodulin-dependent protein kinase". American Journal of Physiology-Heart and Circulatory Physiology 267, n.º 3 (1 de setembro de 1994): H982—H993. http://dx.doi.org/10.1152/ajpheart.1994.267.3.h982.

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Repetitive membrane potential (Em) depolarization from -90 to 0 mV in rabbit and ferret ventricular myocytes induces a facilitation or "staircase" of Ca current (ICa), which is Ca (not Em) dependent and takes several seconds to accumulate and dissipate. That is, ICa at the tenth pulse at 1-2 Hz exceeds that at the first pulse (I10 > I1). The ICa staircase was completely abolished by dialysis with either of two inhibitory peptides of Ca-calmodulin-dependent protein kinase (CaMKII) CaMKII(290-309) and CaMKII(273-302)], implicating this kinase. Inclusion of ATP gamma S in the patch pipette gradually increased ICa but also abolished the staircase implicating phosphorylation. KN-62, a nonpeptide CaMKII inhibitor, reversed the ICa staircase (I1 > I10). However, this effect of KN-62 was largely attributed to a slower recovery from inactivation and a gating shift to more negative Em (not seen with CaMKII peptides). Similar results were obtained with H-89 and staurosporine (inhibitors of adenosine 3',5'-cyclic monophosphate and phospholipid-/Ca-dependent protein kinase, respectively). The reversal of the ICa staircase with H-89 and KN-62 could be prevented by more negative interpulse Em or elevation of extracellular [Ca] (which could counteract changes in channel gating due to a reduction in internal negative surface potential). That is, these kinase inhibitors might decrease phosphorylation at the inner membrane surface. In approximately 30% of the cells studied with H-89 and staurosporine the characteristic kinetic difference in ICa inactivation (faster at I1 than I10) was also diminished. This might be due to a relatively nonspecific inhibition of the same protein kinase inhibited by the CaMKII peptides. We conclude that the Ca-dependent ICa facilitation is due to activation of CaMKII and phosphorylation of a site on or near the Ca channel. KN-62, H-89, and staurosporine shifted ICa gating to more negative potentials and slowed recovery from inactivation, effects that could be due to reduction in phosphorylation at the inner membrane surface. Thus the reversal of the ICa staircase by KN-62, H-89, and staurosporine may not be Ca channel specific.

6

Menegon, A., D. D. Dunlap, F. Castano, F. Benfenati, A. J. Czernik, P. Greengard e F. Valtorta. "Use of phosphosynapsin I-specific antibodies for image analysis of signal transduction in single nerve terminals". Journal of Cell Science 113, n.º 20 (15 de outubro de 2000): 3573–82. http://dx.doi.org/10.1242/jcs.113.20.3573.

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We have developed a semi-quantitative method for indirectly revealing variations in the concentration of second messengers (Ca(2+), cyclic AMP) in single presynaptic boutons by detecting the phosphorylation of the synapsins, excellent nerve terminal substrates for cyclic AMP- and Ca(2+)/calmodulin-dependent protein kinases. For this purpose, we employed polyclonal, antipeptide antibodies recognising exclusively synapsin I phosphorylated by Ca(2+)/calmodulin-dependent protein kinase II (at site 3) or synapsins I/II phosphorylated by either cAMP-dependent protein kinase or Ca(2+)/calmodulin-dependent protein kinase I (at site 1). Cerebellar granular neurones in culture were double-labelled with a monoclonal antibody to synapsins I/II and either of the polyclonal antibodies. Digitised images were analysed to determine the relative phosphorylation stoichiometry at each individual nerve terminal. We have found that: (i) under basal conditions, phosphorylation of site 3 was undetectable, whereas site 1 exhibited some degree of constitutive phosphorylation; (ii) depolarisation in the presence of extracellular Ca(2+) was followed by a selective and widespread increase in site 3 phosphorylation, although the relative phosphorylation stoichiometry varied among individual terminals; and (iii) phosphorylation of site 1 was increased by stimulation of cyclic AMP-dependent protein kinase but not by depolarisation and often occurred in specific nerve terminal sub-populations aligned along axon branches. In addition to shedding light on the regulation of synapsin phosphorylation in living nerve terminals, this approach permits the spatially-resolved analysis of the activation of signal transduction pathways in the presynaptic compartment, which is usually too small to be studied with other currently available techniques.

7

Lu, H. K., R. J. Fern, J. J. Nee e P. Q. Barrett. "Ca(2+)-dependent activation of T-type Ca2+ channels by calmodulin-dependent protein kinase II". American Journal of Physiology-Renal Physiology 267, n.º 1 (1 de julho de 1994): F183—F189. http://dx.doi.org/10.1152/ajprenal.1994.267.1.f183.

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The T-type Ca2+ channel is unique among voltage-dependent Ca2+ channels in its low threshold for opening and its slow kinetics of deactivation. Here, we evaluate the importance of intracellular Ca2+ (Cai2+) in promoting low-threshold gating of T-type channels in adrenal glomerulosa cells. We observe that 390 nM to 1.27 microM Cai2+ enhances T-type current by shifting the voltage dependence of channel activation to more negative potentials. This Ca(2+)-induced shift is mediated by calmodulin-dependent protein kinase II (CaMKII), because it is abolished by inhibitors of CaMKII but not of protein kinase C and is subsequently restored by exogenous calmodulin. This Ca(2+)-induced reduction in gating threshold would render T-type Ca2+ channels uniquely suited to transduce depolarizing stimuli of low amplitude into a Ca2+ signal sufficient to support a physiological response.

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Lecocq, R., F. Lamy, C. Erneux e J. E. Dumont. "Rapid purification and identification of calcyphosine, a Ca2+-binding protein phosphorylated by protein kinase A". Biochemical Journal 306, n.º 1 (15 de fevereiro de 1995): 147–51. http://dx.doi.org/10.1042/bj3060147.

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A method is presented for the rapid purification of dog thyroid calcyphosine, a protein previously identified as a major substrate for cyclic AMP-dependent protein kinase in dog thyroid slices stimulated by thyrotropin [Lecocq, Lamy and Dumont (1979) Eur. J. Biochem. 102, 147-152]. The protein was previously identified as a spot on two-dimensional gels and is now purified in its native form by a procedure involving three chromatographic steps. Homogeneous calcyphosine identified by SDS/PAGE, immunoblotting and peptide sequencing can be obtained within 7 h. As for calmodulin, Ca(2+)-dependent conformational changes can be shown by Ca(2+)-dependent hydrophobic interaction chromatography using phenyl-Sepharose. Unlike calmodulin, calcyphosine is a substrate for protein kinase A.

9

Rokolya, A., M. P. Walsh e R. S. Moreland. "Calcium-and phorbol ester-dependent calponin phosphorylation in homogenates of swine carotid artery". American Journal of Physiology-Heart and Circulatory Physiology 271, n.º 2 (1 de agosto de 1996): H776—H783. http://dx.doi.org/10.1152/ajpheart.1996.271.2.h776.

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Calponin inhibits actin-activated myosin adenosinetriphosphatase (ATPase) activity, and phosphorylation reverses this inhibition. Calponin phosphorylation has been demonstrated in reconstituted contractile protein systems, but studies using intact smooth muscle have produced mixed results. The goal of this study was to determine if vascular smooth muscle contains the necessary biochemical machinery to catalyze calponin phosphorylation. We used swine carotid homogenate, which allows access to the intracellular components and contains all endogenous proteins and enzymes in physiologically relevant concentrations. We demonstrated that calponin is phosphorylated in response to Ca2+ (0.27 +/- 0.04 mol P(i)/mol calponin) and in response to phorbol 12,13-dibutyrate in the presence or absence of Ca2+ (0.48 +/- 0.09 mol P(i)/mol calponin). Calponin phosphorylation was inhibited by the protein kinase C inhibitor staurosporine but not by the Ca(2+)- and calmodulin-dependent protein kinase II inhibitor KN-62. We conclude that Ca(2+)-dependent and -independent isoforms of protein kinase C but not the Ca(2+) -and calmodulin-dependent protein kinase II catalyze calponin phosphorylation in the swine carotid artery.

10

Bosser, R., M. Faura, J. Serratosa, J. Renau-Piqueras, M. Pruschy e O. Bachs. "Phosphorylation of rat liver heterogeneous nuclear ribonucleoproteins A2 and C can be modulated by calmodulin." Molecular and Cellular Biology 15, n.º 2 (fevereiro de 1995): 661–70. http://dx.doi.org/10.1128/mcb.15.2.661.

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It was previously reported that the phosphorylation of three proteins of 36, 40 to 42, and 50 kDa by casein kinase 2 is inhibited by calmodulin in nuclear extracts from rat liver cells (R. Bosser, R. Aligué, D. Guerini, N. Agell, E. Carafoli, and O. Bachs, J. Biol. Chem. 268:15477-15483, 1993). By immunoblotting, peptide mapping, and endogenous phosphorylation experiments, the 36- and 40- to 42-kDa proteins have been identified as the A2 and C proteins, respectively, of the heterogeneous nuclear ribonucleoprotein particles. To better understand the mechanism by which calmodulin inhibits the phosphorylation of these proteins, they were purified by using single-stranded DNA chromatography, and the effect of calmodulin on their phosphorylation by casein kinase 2 was analyzed. Results revealed that whereas calmodulin inhibited the phosphorylation of purified A2 and C proteins in a Ca(2+)-dependent manner, it did not affect the casein kinase 2 phosphorylation of a different protein substrate, i.e., beta-casein. These results indicate that the effect of calmodulin was not on casein kinase 2 activity but on specific protein substrates. The finding that the A2 and C proteins can bind to a calmodulin-Sepharose column in a Ca(2+)-dependent manner suggests that this association could prevent the phosphorylation of the proteins by casein kinase 2. Immunoelectron microscopy studies have revealed that such interactions could also occur in vivo, since calmodulin and A2 and C proteins colocalize on the ribonucleoprotein particles in rat liver cell nuclei.

11

Ruiz, O. S., e J. A. Arruda. "Regulation of the renal Na-HCO3 cotransporter by cAMP and Ca-dependent protein kinases". American Journal of Physiology-Renal Physiology 262, n.º 4 (1 de abril de 1992): F560—F565. http://dx.doi.org/10.1152/ajprenal.1992.262.4.f560.

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Changes in the activity of the brush-border Na-H antiporter are accompanied by parallel changes in the activity of the Na-HCO3 cotransporter. Adenosine 3',5'-cyclic monophosphate (cAMP) and calmodulin inhibit the Na-H antiporter, whereas protein kinase C (PKC) stimulates it. We hypothesized that cAMP, calmodulin, and PKC should have similar effects on the Na-HCO3 cotransporter activity. Phosphorylated renal basolateral membranes were treated with either cAMP, calmodulin, or phorbol ester. cAMP, 1 microM, inhibited HCO3-dependent 22Na uptake without affecting 22Na uptake in presence of gluconate, suggesting that cAMP inhibits Na-HCO3 cotransporter activity without altering diffusive 22Na uptake. The effect of cAMP to inhibit the Na-HCO3 cotransporter could also be elicited by the catalytic subunit of cAMP, and this inhibitory effect was prevented by the protein kinase A (PKA) inhibitor. Calmodulin (1 microM), in presence of Ca, also inhibited HCO3-dependent 22Na uptake in presence of HCO3, whereas 22Na uptake in the presence of gluconate was unchanged. The inhibitory effect of calmodulin on HCO3-dependent 22Na uptake was prevented by N-(4-aminobutyl)-5-chloro-2-naphthalene sulfonamide (W-13), an inhibitor of calmodulin. Phorbol 12-myristate 13-acetate and PKC stimulated Na-HCO3 cotransporter activity, whereas the inactive analogue, 4 alpha-phorbol, failed to elicit such a stimulation. Basolateral membranes displayed cAMP-dependent and Ca-dependent protein kinase activities. Thus PKA and Ca-dependent protein kinases regulate the activity of the Na-HCO3 cotransporter and suggest that hormones that act through these systems modulate the activity of the Na-HCO3 cotransporter.

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Zelikovic, I., e J. Przekwas. "Ca(2+)-dependent protein kinases modulate proline transport across the renal brush-border membrane". American Journal of Physiology-Renal Physiology 268, n.º 1 (1 de janeiro de 1995): F155—F162. http://dx.doi.org/10.1152/ajprenal.1995.268.1.f155.

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The cellular mechanisms controlling reabsorption of amino acids in the renal proximal tubule are unknown. Ca(2+)-dependent protein kinases modulate the activity of several ion channels and carriers in the kidney. The role of these enzymes in regulating tubular amino acid transport has not been established. We investigated the effect of Ca(2+)- and phospholipid-dependent protein kinase C (PKC) and Ca2+/calmodulin-dependent protein kinase II (CaMK II) on Na(+)- and Cl(-)-dependent proline transport across the rat renal brush-border membrane (BBM). Bioassays utilizing selective peptide substrates for Ca(2+)-dependent protein kinases demonstrated the presence of PKC and CaMK II in the BBM. Renal brush-border membrane vesicles (BBMV) were phosphorylated using the "hyposmotic shock" technique. Endogenous (membrane-bound) CaMK II and PKC, as well as exogenous, highly purified PKC inhibited NaCl-linked proline uptake by phosphorylated, lysed/resealed BBMV compared with control vesicles. The inhibitory effect of Ca2+ on proline transport, without the presence of other kinase activators, was mediated by activation of endogenous CaMK II. The CaMK II- and PKC-induced inhibition of proline uptake was reversed by the specific kinase inhibitor peptides CaMK II-(281-302) and PKC-(19-31), respectively. These data suggest that Ca(2+)-dependent protein kinase-mediated phosphorylation inhibits NaCl-dependent proline transport across the tubular luminal membrane.

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Gonda, K., M. Katoh, K. Hanyu, Y. Watanabe e O. Numata. "Ca(2+)/calmodulin and p85 cooperatively regulate an initiation of cytokinesis in Tetrahymena". Journal of Cell Science 112, n.º 21 (1 de novembro de 1999): 3619–26. http://dx.doi.org/10.1242/jcs.112.21.3619.

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Tetrahymena p85 differs in mobility in two-dimensional SDS-polyacrylamide gel electrophoresis between wild-type and temperature-sensitive cell-division-arrest mutant cdaA1 cell extracts, and is localized to the presumptive division plane before the formation of the division furrow. The p85 contained three identical sequences which show homology to the calmodulin binding site of Ca(2+)/calmodulin dependent protein kinase Type II in Saccharomyces cerevisiae. We found the p85 directly interacts with Tetrahymena calmodulin in a Ca(2+)-dependent manner, using a co-sedimentation assay. We next examined the localization of p85 and calmodulin during cytokinesis using indirect immunofluorescence. The results showed that both proteins colocalize in the division furrow. This is the first observation that calmodulin is localized in the division furrow. Moreover, the direct interaction between p85 and Ca(2+)/calmodulin was inhibited by Ca(2+)/calmodulin inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide HCl. When the cells were treated with the drug just before the beginning of cytokinesis, the drug also inhibited the localization of p85 and calmodulin to the division plane, and the formation of the contractile ring and division furrow. Therefore, we propose that the Ca(2+)/calmodulin signal and its target protein p85 cooperatively regulate an initiation of cytokinesis and may be also concerned with the progression of cytokinesis in Tetrahymena.

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Sugiyama, Yasunori, Atsuhiko Ishida, Noriyuki Sueyoshi e Isamu Kameshita. "Tyrosine kinase activity of a Ca 2+ /calmodulin-dependent protein kinase II catalytic fragment". Biochemical and Biophysical Research Communications 377, n.º 2 (dezembro de 2008): 648–52. http://dx.doi.org/10.1016/j.bbrc.2008.10.028.

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15

Proud, Christopher G. "Regulation and roles of elongation factor 2 kinase". Biochemical Society Transactions 43, n.º 3 (1 de junho de 2015): 328–32. http://dx.doi.org/10.1042/bst20140323.

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Eukaryotic elongation factor 2 kinase (eEF2K) belongs to the small family of atypical protein kinases termed α-kinases, and is the only calcium/calmodulin (Ca/CaM)-dependent member of that group. It phosphorylates and inactivates eEF2, to slow down the rate of elongation, the stage in mRNA translation that consumes almost all the energy and amino acids consumed by protein synthesis. In addition to activation by Ca/CaM, eEF2K is also regulated by an array of other regulatory inputs, which include inhibition by the nutrient- and growth-factor activated signalling pathways. Recent evidence shows that eEF2K plays an important role in learning and memory, processes that require the synthesis of new proteins and involve Ca-mediated signalling. eEF2K is activated under conditions of nutrient and energy depletion. In cancer cells, or certain tumours, eEF2K exerts cytoprotective effects, which probably reflect its ability to inhibit protein synthesis, and nutrient consumption, under starvation conditions. eEF2K is being evaluated as a potential therapeutic target in cancer.

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Kim, Inkyeom, Hyun‐Dong Je, Cynthia Gallant, Qian Zhan, Dee Van Riper, John A. Badwey, Harold A. Singer e Kathleen G. Morgan. "Ca 2+ ‐calmodulin‐dependent protein kinase II‐dependent activation of contractility in ferret aorta". Journal of Physiology 526, n.º 2 (julho de 2000): 367–74. http://dx.doi.org/10.1111/j.1469-7793.2000.00367.x.

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Park, C. S., S. H. Chang, H. S. Lee, S. H. Kim, J. W. Chang e C. D. Hong. "Inhibition of renin secretion by Ca2+ through activation of myosin light chain kinase". American Journal of Physiology-Cell Physiology 271, n.º 1 (1 de julho de 1996): C242—C247. http://dx.doi.org/10.1152/ajpcell.1996.271.1.c242.

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This study sought to identify specific enzyme(s) involved in the biochemical cascade of inhibition of renin secretion through Ca(2+)-calmodulin mediation with the use of inhibitors of protein kinase and phosphatases. Inhibition of renin secretion mediated by Ca(2+)-calmodulin was induced by incubating rat renal cortical slices in K(+)-rich depolarizing medium, producing > 50% inhibition. This inhibition was completely blocked by the calmodulin antagonist calmidazolium. The inhibitor of protein kinase with broad specificity, K-252a, blocked the inhibition of renin secretion. Neither KN-62, a specific inhibitor of Ca(2+)-calmodulin-dependent protein kinase II (CaMK II), nor specific inhibitors of protein phosphatase 2B (PP2B), cyclosporin A and FK-506, blocked the inhibition. On the other hand, all four known inhibitors specific for myosin light chain kinase (MLCK), with different chemical structures and mechanisms of inhibition (ML-9, ML-7, KT-5926 and wortmannin), almost completely protected renin secretion against the inhibition by Ca2+. In particular, ML-9 reversively protected > 77% secretion against the inhibition both in K(+)-rich medium alone and in combination with the calcium ionophore A-23187 in a concentration-dependent manner. Together, these findings from our present study provide the first evidence, albeit indirect in nature, for the possibility that activation of Ca(2+)-calmodulin-dependent MLCK at the downstream of Ca2+ influx into juxtaglomerular (JG) cells leads to phosphorylation of 20-kDa regulatory myosin light chain (MLC20). Through interaction with actin, the phosphorylated MLC20 may play an important role in the inhibitory stimulus-secretion coupling of renin.

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Zhao, D. Y., M. D. Hollenberg e D. L. Severson. "Calmodulin inhibits the protein kinase C-catalysed phosphorylation of an endogenous protein in A10 smooth-muscle cells". Biochemical Journal 277, n.º 2 (15 de julho de 1991): 445–50. http://dx.doi.org/10.1042/bj2770445.

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The protein kinase C (PKC) activator phorbol 12,13-dibutyrate stimulated the phosphorylation of a 75 kDa protein (p75) in intact cultured A10 smooth-muscle cells and sonicated cell preparations; p75 was the only major substrate for endogenous PKC in sonicated A10 cells. The Ca(2+)-dependent phosphorylation of p75 in vitro was dramatically decreased in PKC-down-regulated A10 cells; however, p75 from identical sonicated cell preparations was still phosphorylated by an exogenous aortic PKC preparation. Calmodulin inhibited the phosphorylation of p75 by PKC, but not the phosphorylation of other PKC substrates (platelet P47 protein and histone). The addition of calmodulin after the phosphorylation reaction was started prevented further phosphorylation, but did not decrease the extent of phosphorylation of p75 that was reached before the addition of calmodulin. The inhibition of p75 phosphorylation was concentration-dependent, with IC50 values (concn. giving 50% inhibition) ranging from less than 0.5 to 10 micrograms of calmodulin/ml, and was Ca(2+)-dependent, requiring a free Ca2+ concentration of 10 microM or greater. These results suggest that the inhibition of the PKC-catalysed phosphorylation of p75 by calmodulin may be due to its interaction with the substrate, rather than a direct inhibitory effect on the enzyme, and that this inhibition could be regulated by intracellular Ca2+ concentration. Therefore, p75 may be a physiological link between the PKC and Ca2+/calmodulin pathways.

19

Frindt, G., L. G. Palmer e E. E. Windhager. "Feedback regulation of Na channels in rat CCT. IV. Mediation by activation of protein kinase C". American Journal of Physiology-Renal Physiology 270, n.º 2 (1 de fevereiro de 1996): F371—F376. http://dx.doi.org/10.1152/ajprenal.1996.270.2.f371.

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The hypothesis that feedback inhibition of the apical Na+ channels in the cortical collecting tubule (CCT) is mediated by activation of a Ca(2+)-dependent protein kinase was tested using the patch-clamp technique. Na+ channel activity was monitored in cell-attached patches in principal cells of split-open rat tubules. Mean number of open channels (NPo) and single-channel current (i) were measured at 37 degrees C during continuous tubule superfusion. Phorbol 12-myristate 13-acetate (PMA; 50 nM), an activator of protein kinase C (PKC), decreased NPo to 33% of the control value. Staurosporine (200 nM), an inhibitor of PKC and of Ca(2+)-calmodulin kinase II, practically abolished the effect of PMA. Ouabain (1 mM), reduced NPo to 29% of control values and decreased i. Ouabain did not downregulate the channels in tubules exposed to staurosporine, although it still reduced i. Incubation of the tubules with 10 microM KN-62, a specific cell membrane-permeable inhibitor of Ca(2+)-calmodulin kinase II, did not interfere with the ouabain-dependent downregulation of the channels. The results support the view that the downregulation caused by ouabain involves the Ca(2+)-dependent phosphorylation of the channel itself or of proteins regulating the channel.

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Sacks, D. B., H. W. Davis, J. P. Williams, E. L. Sheehan, J. G. N. Garcia e J. M. McDonald. "Phosphorylation by casein kinase II alters the biological activity of calmodulin". Biochemical Journal 283, n.º 1 (1 de abril de 1992): 21–24. http://dx.doi.org/10.1042/bj2830021.

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Calmodulin is the major intracellular Ca(2+)-binding protein, providing Ca(2+)-dependent regulation of numerous intracellular enzymes. The phosphorylation of calmodulin may provide an additional mechanism for modulating its function as a signal transducer. Phosphocalmodulin has been identified in tissues and cells, and calmodulin is phosphorylated both in vitro and in intact cells by various enzymes. Phosphorylation of calmodulin on serine/threonine residues by casein kinase II decreases its ability to activate both myosin-light-chain kinase and cyclic nucleotide phosphodiesterase. For myosin-light-chain kinase the primary effect is an inhibition of the Vmax. of the reaction, with no apparent change in the concentration at which half-maximal velocity is attained (K0.5) for either Ca2+ or calmodulin. In contrast, for phosphodiesterase, phosphorylation of calmodulin significantly increases the K0.5 for calmodulin without noticeably altering the Vmax. or the K0.5 for Ca2+. The higher the stoichiometry of phosphorylation of calmodulin, the greater the inhibition of calmodulin-stimulated activity for both enzymes. Therefore the phosphorylation of calmodulin by casein kinase II appears to provide a Ca(2+)-independent mechanism whereby calmodulin regulates at least two important target enzymes, myosin-light-chain kinase and cyclic nucleotide phosphodiesterase.

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Zhang, Rong-Huai, Haitao Guo, Machender R. Kandadi, Xiao-Ming Wang e Jun Ren. "Ca+2/Calmodulin-Dependent Protein Kinase Mediates Glucose Toxicity-Induced Cardiomyocyte Contractile Dysfunction". Experimental Diabetes Research 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/829758.

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(1) Hyperglycemia leads to cytotoxicity in the heart. Although several theories are postulated for glucose toxicity-induced cardiomyocyte dysfunction, the precise mechanism still remains unclear. (2) This study was designed to evaluate the impact of elevated extracellular Ca2+on glucose toxicity-induced cardiac contractile and intracellular Ca2+anomalies as well as the mechanism(s) involved with a focus on Ca2+/calmodulin (CaM)-dependent kinase. Isolated adult rat cardiomyocytes were maintained in normal (NG, 5.5 mM) or high glucose (HG, 25.5 mM) media for 6-12 hours. Contractile indices were measured including peak shortening (PS), maximal velocity of shortening/relengthening (±dL/dt), time-to-PS (TPS), and time-to-90% relengthening (TR90). (3) Cardiomyocytes maintained with HG displayed abnormal mechanical function including reduced PS, ±dL/dt, and prolonged TPS, TR90and intracellular Ca2+clearance. Expression of intracellular Ca2+regulatory proteins including SERCA2a, phospholamban and Na+-Ca2+exchanger were unaffected whereas SERCA activity was inhibited by HG. Interestingly, the HG-induced mechanical anomalies were abolished by elevated extracellular Ca2+(from 1.0 to 2.7 mM). Interestingly, the high extracellular Ca2+-induced beneficial effect against HG was abolished by the CaM kinase inhibitor KN93. (4) These data suggest that elevated extracellular Ca2+protects against glucose toxicity-induced cardiomyocyte contractile defects through a mechanism associated with CaM kinase.

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Fern, R. J., M. S. Hahm, H. K. Lu, L. P. Liu, F. S. Gorelick e P. Q. Barrett. "Ca2+/calmodulin-dependent protein kinase II activation and regulation of adrenal glomerulosa Ca2+ signaling". American Journal of Physiology-Renal Physiology 269, n.º 6 (1 de dezembro de 1995): F751—F760. http://dx.doi.org/10.1152/ajprenal.1995.269.6.f751.

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We recently reported that elevations in the intracellular Ca2+ concentration ([Ca2+]i) enhance low-voltage-activated, T-type, Ca2+ channel activity via Ca2+/calmodulin-dependent protein kinase II (CaMKII). Here, we document CaMKII activity in bovine adrenal glomerulosa (AG) cells and assess the importance of CaMKII in depolarization-induced Ca2+ signaling. AG cell extracts exhibited kinase activity toward a CaMKII-selective peptide substrate that was dependent on both Ca2+ [half-maximal concentration for Ca2+ activation (K0.5) = 1.5 microM] and calmodulin (K0.5 = 46 nM) and was sensitive to a calmodulin antagonist and a CaMKII peptide inhibitor. On cell treatment with elevated extracellular potassium (10-60 mM) or angiotensin II, Ca(2+)-independent CaMKII activity increased to 133-205% of basal activity. Ca(2+)-independent kinase activity in agonist-stimulated extracts was inhibited by the CaMKII inhibitor peptide, 1(-)[N,O-bis(1,5- isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN-62), a cell-permeable inhibitor of CaMKII, reduced the agonist-induced stimulation of Ca(2+)-independent CaMKII activity. KN-62 also diminished depolarization-induced increases in [Ca2+]i without affecting the membrane potential. These observations suggest that CaMKII is activated in situ by aldosterone secretagogues and augments Ca2+ signaling through voltage-gated Ca2+ channels.

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Matthews, R. P., C. R. Guthrie, L. M. Wailes, X. Zhao, A. R. Means e G. S. McKnight. "Calcium/calmodulin-dependent protein kinase types II and IV differentially regulate CREB-dependent gene expression." Molecular and Cellular Biology 14, n.º 9 (setembro de 1994): 6107–16. http://dx.doi.org/10.1128/mcb.14.9.6107.

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Phosphorylation of CREB (cyclic AMP [cAMP]- response element [CRE]-binding protein) by cAMP-dependent protein kinase (PKA) leads to the activation of many promoters containing CREs. In neurons and other cell types, CREB phosphorylation and activation of CRE-containing promoters can occur in response to elevated intracellular Ca2+. In cultured cells that normally lack this Ca2+ responsiveness, we confer Ca(2+)-mediated activation of a CRE-containing promoter by introducing an expression vector for Ca2+/calmodulin-dependent protein kinase type IV (CaMKIV). Activation could also be mediated directly by a constitutively active form of CaMKIV which is Ca2+ independent. The CaMKIV-mediated gene induction requires the activity of CREB/ATF family members but is independent of PKA activity. In contrast, transient expression of either a constitutively active or wild-type Ca2+/calmodulin-dependent protein kinase type II (CaMKII) fails to mediate the transactivation of the same CRE-containing reporter gene. Examination of the subcellular distribution of transiently expressed CaMKIV and CaMKII reveals that only CaMKIV enters the nucleus. Our results demonstrate that CaMKIV, which is expressed in neuronal, reproductive, and lymphoid tissues, may act as a mediator of Ca(2+)-dependent gene induction.

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Matthews, R. P., C. R. Guthrie, L. M. Wailes, X. Zhao, A. R. Means e G. S. McKnight. "Calcium/calmodulin-dependent protein kinase types II and IV differentially regulate CREB-dependent gene expression". Molecular and Cellular Biology 14, n.º 9 (setembro de 1994): 6107–16. http://dx.doi.org/10.1128/mcb.14.9.6107-6116.1994.

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Phosphorylation of CREB (cyclic AMP [cAMP]- response element [CRE]-binding protein) by cAMP-dependent protein kinase (PKA) leads to the activation of many promoters containing CREs. In neurons and other cell types, CREB phosphorylation and activation of CRE-containing promoters can occur in response to elevated intracellular Ca2+. In cultured cells that normally lack this Ca2+ responsiveness, we confer Ca(2+)-mediated activation of a CRE-containing promoter by introducing an expression vector for Ca2+/calmodulin-dependent protein kinase type IV (CaMKIV). Activation could also be mediated directly by a constitutively active form of CaMKIV which is Ca2+ independent. The CaMKIV-mediated gene induction requires the activity of CREB/ATF family members but is independent of PKA activity. In contrast, transient expression of either a constitutively active or wild-type Ca2+/calmodulin-dependent protein kinase type II (CaMKII) fails to mediate the transactivation of the same CRE-containing reporter gene. Examination of the subcellular distribution of transiently expressed CaMKIV and CaMKII reveals that only CaMKIV enters the nucleus. Our results demonstrate that CaMKIV, which is expressed in neuronal, reproductive, and lymphoid tissues, may act as a mediator of Ca(2+)-dependent gene induction.

25

Fischer, Thomas H., Jonas Herting, Theodor Tirilomis, André Renner, Stefan Neef, Karl Toischer, David Ellenberger et al. "Ca 2+ /Calmodulin-Dependent Protein Kinase II and Protein Kinase A Differentially Regulate Sarcoplasmic Reticulum Ca 2+ Leak in Human Cardiac Pathology". Circulation 128, n.º 9 (27 de agosto de 2013): 970–81. http://dx.doi.org/10.1161/circulationaha.113.001746.

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Gao, Zhan, Madhu V. Singh, Duane D. Hall, Olha M. Koval, Elizabeth D. Luczak, Mei-ling A. Joiner, Biyi Chen et al. "Catecholamine-Independent Heart Rate Increases Require Ca 2+ /Calmodulin-Dependent Protein Kinase II". Circulation: Arrhythmia and Electrophysiology 4, n.º 3 (junho de 2011): 379–87. http://dx.doi.org/10.1161/circep.110.961771.

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Vinogradova, Tatiana M., Ying-Ying Zhou, Konstantin Y. Bogdanov, Dongmei Yang, Meike Kuschel, Heping Cheng e Rui-Ping Xiao. "Sinoatrial Node Pacemaker Activity Requires Ca 2+ /Calmodulin-Dependent Protein Kinase II Activation". Circulation Research 87, n.º 9 (27 de outubro de 2000): 760–67. http://dx.doi.org/10.1161/01.res.87.9.760.

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Burns, K. D., T. Homma e R. C. Harris. "Regulation of Na(+)-H+ exchange by ATP depletion and calmodulin antagonism in renal epithelial cells". American Journal of Physiology-Renal Physiology 261, n.º 4 (1 de outubro de 1991): F607—F616. http://dx.doi.org/10.1152/ajprenal.1991.261.4.f607.

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The present studies examined effects of ATP depletion and calmodulin antagonism on stimulation of Na(+)-H+ exchange by cytosolic acidification in renal epithelial cells (LLC-PK1). ATP depletion significantly inhibited both amiloride-sensitive 22Na+ uptake (P less than 0.001; n = 12) and Na(+)-dependent intracellular pH (pHi) recovery in 2',7'-bis (carboxyethyl)-5(6)-carboxyfluorescein acetoxymethylester (BCECF/AM)-loaded cells. Calmodulin antagonists, N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7) and calmidazolium, both caused a concentration-dependent inhibition of Na(+)-H+ exchange activity. The W-7-induced inhibition of Na(+)-H+ exchange occurred in cells incubated for 24 h with phorbol 12-myristate 13-acetate, indicating that the effect of W-7 was not mediated by protein kinase C inhibition. Both W-7 and ATP depletion shifted the pHi dependence of the antiporter, and ATP depletion also reduced the maximal activity. In LLC-PK1/CL4 cells grown on permeable filters, W-7 inhibited the cytosolic acidification-stimulated basolateral exchanger by 54 +/- 5% (P less than 0.005; n = 7) and, in contrast, stimulated the apical exchanger by 28 +/- 13% (P less than 0.05; n = 6). ATP depletion significantly inhibited apical Na(+)-H+ exchange. These results suggest that an ATP-Ca(2+)-calmodulin-dependent process is involved in regulation of Na(+)-H+ exchange in LLC-PK1 cells. A Ca(2+)-calmodulin-dependent process activated the amiloride-sensitive basolateral Na(+)-H+ exchanger and inhibited the amiloride-resistant apical antiporter. Phosphorylation of these two Na(+)-H+ exchangers or regulatory proteins by a Ca(2+)-calmodulin-dependent protein kinase may mediate this differential regulation.

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Zhang, C., R. J. Paul e E. G. Kranias. "Calmodulin stimulation of smooth muscle plasmalemmal vesicle Ca2+ uptake: direct or indirect effect?" American Journal of Physiology-Heart and Circulatory Physiology 263, n.º 2 (1 de agosto de 1992): H366—H371. http://dx.doi.org/10.1152/ajpheart.1992.263.2.h366.

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Current evidence suggests that Ca(2+)-calmodulin-dependent protein kinase(s) may be involved in the regulation of smooth muscle contractility. The plasmalemmal Ca2+ pump plays an important role in smooth muscle contractility, and this pump is stimulated by calmodulin. However, it is not known whether this is due to direct activation, or calmodulin-dependent protein phosphorylation, or both. We tested these hypotheses using a plasma membrane vesicle preparation from porcine antral smooth muscle. Inclusion of calmodulin in the Ca(2+)-uptake assay decreased the free Ca2+ concentration at which Ca2+ uptake is 50% of the maximal rate (1.5 +/- 0.21 to 0.84 +/- 0.06 microM) of the Ca2+ pump for Ca2+, without changing maximal rate of Ca2+ uptake (Vmax) (8.0 +/- 1.1 to 8.4 +/- 0.7 nmol.min-1.mg-1). In contrast, prephosphorylation in the absence of Ca(2+)-calmodulin increased Ca(2+)-uptake rates at both low (pCa 6.0) and high Ca2+ concentration (pCa 5.0), suggesting an increase in Vmax. Further phosphorylation in the presence of Ca(2+)-calmodulin was not associated with any further increases in the Ca(2+)-uptake rates at pCa 6.0. However, inclusion of calmodulin in the Ca(2+)-uptake assays stimulated the rates (pCa 6.0) of both unphosphorylated and prephosphorylated vesicles to a similar extent. These findings suggest that the stimulation of the smooth muscle plasmalemmal Ca2+ pump by calmodulin is predominantly due to a direct effect via a mechanism distinct from that by plasma membrane phosphorylation.

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Dayton, J. S., e A. R. Means. "Ca(2+)/calmodulin-dependent kinase is essential for both growth and nuclear division in Aspergillus nidulans." Molecular Biology of the Cell 7, n.º 10 (outubro de 1996): 1511–19. http://dx.doi.org/10.1091/mbc.7.10.1511.

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The calmodulin gene has been shown to be essential for cell cycle progression in a number of eukaryotic organisms. In vertebrates and Aspergillus nidulans the calmodulin dependence also requires calcium. We demonstrate that the unique gene encoding a multifunctional calcium/calmodulin-dependent protein kinase (CaMK) is also essential in A. nidulans. This enzyme is required both for the nuclear division cycle and for hyphal growth, because spores containing the disrupted gene arrest with a single nucleus and fail to extend a germ tube. A strain conditional for the expression of CaMK was created. When grown under conditions that resulted in a 90% decrease in the enzyme, both nuclear division and growth were markedly slowed. The CaMK seems to be important for progression from G2 to mitosis.

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Okafor, M. C., R. J. Schiebinger e D. R. Yingst. "Evidence for a calmodulin-dependent phospholipase A2 that inhibits Na-K-ATPase". American Journal of Physiology-Cell Physiology 272, n.º 4 (1 de abril de 1997): C1365—C1372. http://dx.doi.org/10.1152/ajpcell.1997.272.4.c1365.

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We tested whether calnaktin, a proposed Ca/calmodulin (CaM)-dependent protein that inhibits the Na-K-ATPase, was a kinase, a phosphatase, a phospholipase A2 (PLA2), or a Ca-dependent protease. Human red blood cell membranes were extracted to remove associated calmodulin but to retain the proposed endogenous calnaktin. Exclusively cytoplasmic proteins and cofactors were presumably absent. In these membranes, free Ca inhibited the Na-K-ATPase with an inhibition constant (K[i]) of > or = 9 microM at a Na concentration of 18 mM. Addition of 100 nM CaM decreased the Ki to < 2 microM and increased the percent inhibition at 2 microM free Ca from 18 +/- 1 to 68 +/- 2%. The inhibitory effect of Ca/CaM was reversible, indicating that calnaktin is not a protease. Neither staurosporine (500 nM), 1-(N,O-bis[5-isoquinolinesulfonyl]-N-methyl-L-tyrosyl)-4-phenylpipera zin e (5 microM), nor genistein (100 microM) diminished Ca/CaM inhibition of the Na-K-ATPase. Thus there is no evidence that this protein is a kinase. Likewise, the phosphatase inhibitors microcystin (1 microM) and okadaic acid (10 microM) had no effect. PLA2 inhibitors arachidonyl trifluoromethyl ketone (AACOCF3), parabromophenacyl bromide (pBPB), and quinacrine all abolished Ca/CaM inhibition of the Na-K-ATPase. Ca/CaM also increased PLA2 activity, as reflected by an increase in the slope of fluorescence signal of 10-pyrene phosphatidylcholine, a substrate for PLA2. This Ca/CaM-induced change in slope was inhibited by both pBPB and AACOCF3. These data suggest that human red cell membranes contain a form of PLA2 that is activated by Ca/CaM and that this enzyme may mediate Ca/CaM inhibition of the Na-K-ATPase.

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Rose, Adam J., e Mark Hargreaves. "Exercise Increases Ca 2+ –Calmodulin‐Dependent Protein Kinase II Activity in Human Skeletal Muscle". Journal of Physiology 553, n.º 1 (novembro de 2003): 303–9. http://dx.doi.org/10.1113/jphysiol.2003.054171.

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Kockskämper, Jens, e Burkert Pieske. "Phosphorylation of the Cardiac Ryanodine Receptor by Ca 2+ /Calmodulin-Dependent Protein Kinase II". Circulation Research 99, n.º 4 (18 de agosto de 2006): 333–35. http://dx.doi.org/10.1161/01.res.0000239406.66844.7d.

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Morris, A. P., e R. A. Frizzell. "Ca(2+)-dependent Cl- channels in undifferentiated human colonic cells (HT-29). II. Regulation and rundown". American Journal of Physiology-Cell Physiology 264, n.º 4 (1 de abril de 1993): C977—C985. http://dx.doi.org/10.1152/ajpcell.1993.264.4.c977.

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The regulation of 15-pS Cl- channels by Ca(2+)-mobilizing agonists was investigated by simultaneous cell-attached patch and intracellular Ca2+ concentration ([Ca2+]i) measurements. Cells were loaded with a synthetic peptide made from the calmodulin binding domain of Ca2+/calmodulin-dependent protein kinase II. This caused inhibition of Cl- channel activity without any corresponding effect on either agonist-induced [Ca2+]i mobilization or K+ channel activation. Calmodulin therefore confers Ca2+ sensitivity to the 15-pS channel. When patches were excised from the cell, Cl- channel activity ran down. Channel rundown was not reversed by ATP or calmodulin. When recording from cell-attached patches of detergent-treated cells, similar phenomenology was observed. Therefore, other factors that are lost upon plasma membrane permeabilization are required for the functioning of Ca(2+)-dependent Cl- channels. After rundown of these channels, a large-conductance, multistate, Ca(2+)-insensitive Cl- channel was seen. The smallest subconductance state of this channel was of similar magnitude to that of the Ca(2+)-dependent Cl- channel. Furthermore, its voltage and halide sensitivities were similar to those reported for the 15-pS Cl- channel and Ca(2+)-dependent whole cell Cl- currents. Because this channel is not observed in the intact cell, this may be a remnant conductance of the Ca(2+)-sensitive 15-pS Cl- channel.

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Schweitzer, E. S., M. J. Sanderson e C. G. Wasterlain. "Inhibition of regulated catecholamine secretion from PC12 cells by the Ca2+/calmodulin kinase II inhibitor KN-62". Journal of Cell Science 108, n.º 7 (1 de julho de 1995): 2619–28. http://dx.doi.org/10.1242/jcs.108.7.2619.

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When stimulated by the cholinergic agonist carbachol, PC12 cells rapidly secrete a large fraction of the intracellular catecholamines by exocytotic release from the large dense-core secretory vesicles in a Ca(2+)-dependent manner. To investigate whether Ca2+/calmodulin kinase II plays a role in the regulated secretion of catecholamines, we examined the effect of the specific Ca2+/calmodulin kinase II inhibitor KN-62 on the carbachol-induced release of norepinephrine from PC12 cells. Approximately 50% of the regulated release of norepinephrine, stimulated either by carbachol or direct depolarization, was inhibited by pretreatment with KN-62, while the remaining 50% was resistant to KN-62 and therefore independent of Ca2+/calmodulin kinase II. In contrast, H7, an inhibitor of protein kinase C, had no effect on any of the stimulated release. FURA 2 imaging experiments demonstrated that KN-62 does not act by blocking the stimulation-induced increase in intracellular [Ca2+]. The most likely model consistent with these data is that all the dense-core vesicles fuse with the plasma membrane in a Ca(2+)-dependent process, but that approximately 50% of the vesicles require an additional step that is dependent on the action of Ca2+/calmodulin kinase II. This step occurs between the influx of Ca2+ and the fusion of vesicle membranes with the plasma membrane, and may be analogous to the Ca2+/calmodulin kinase II phosphorylation of synapsin which mobilizes small, clear synaptic vesicles for exocytosis at the synapse.

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Hsu, Li-Sung, Ann-Ping Tsou, Chin-Wen Chi, Chen-Hsen Lee e Jeou-Yuan Chen. "Cloning, Expression and Chromosomal Localization of Human Ca²⁺/Calmodulin-Dependent Protein Kinase Kinase". Journal of Biomedical Science 5, n.º 2 (1998): 141–49. http://dx.doi.org/10.1159/000025324.

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Zohn, I. E., H. Yu, X. Li, A. D. Cox e H. S. Earp. "Angiotensin II stimulates calcium-dependent activation of c-Jun N-terminal kinase." Molecular and Cellular Biology 15, n.º 11 (novembro de 1995): 6160–68. http://dx.doi.org/10.1128/mcb.15.11.6160.

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In GN4 rat liver epithelial cells, angiotensin II (Ang II) and other agonists which activate phospholipase C stimulate tyrosine kinase activity in a calcium-dependent, protein kinase C (PKC)-independent manner. Since Ang II also produces a proliferative response in these cells, we investigated downstream signaling elements traditionally linked to growth control by tyrosine kinases. First, Ang II, like epidermal growth factor (EGF), stimulated AP-1 binding activity in a PKC-independent manner. Because increases in AP-1 can reflect induction of c-Jun and c-Fos, we examined the activity of the mitogen-activated protein (MAP) kinase family members Erk-1 and -2 and the c-Jun N-terminal kinase (JNK), which are known to influence c-Jun and c-Fos transcription. Ang II stimulated MAP kinase (MAPK) activity but only approximately 50% as effectively as EGF; again, these effects were independent of PKC. Ang II also produced a 50- to 200-fold activation of JNK in a PKC-independent manner. Unlike its smaller effect on MAPK, Ang II was approximately four- to sixfold more potent in activating JNK than EGF was. Although others had reported a lack of calcium ionophore-stimulated JNK activity in lymphocytes and several other cell lines, we examined the role of calcium in GN4 cells. The following results suggest that JNK activation in rat liver epithelial cells is at least partially Ca(2+) dependent: (i) norepinephrine and vasopressin hormones that increase inositol 1,4,5-triphosphate stimulated JNK; (ii) both thapsigargin, a compound that produces an intracellular Ca(2+) signal, and Ca(2+) ionophores stimulated a dramatic increase in JNK activity (up to 200-fold); (iii) extracellular Ca(2+) chelation with ethylene glycol tetraacetic acid (EGTA) inhibited JNK activation by ionophore and intracellular chelation with 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl-ester (BAPTA-AM) partially inhibited JNK activation by Ang II or thapsigargin; and (iv) JNK activation by Ang II was inhibited by pretreatment of cells with thapsigargin and EGTA, a procedure which depletes intracellular Ca(2+) stores. JNK activation following Ang II stimulation did not involve calmodulin; either W-7 nor calmidizolium, in concentrations sufficient to inhibit Ca(2+)/calmodulin-dependent kinase II, blocked JNK activation by Ang II. In contrast, genistein, in concentrations sufficient to inhibit Ca(2+)-dependent tyrosine phosphorylation, prevented Ang II and thapsigargin-induced JNK activation. In summary, in GN4 rat liver epithelial cells, Ang II stimulates JNK via a novel Ca(2+)-dependent pathway. The inhibition by genistein suggest that Ca(2+)-dependent tyrosine phosphorylation may modulate the JNK pathway in a cell type-specific manner, particularly in cells with a readily detectable Ca(2+)-regulated tyrosine kinase.

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Omar Faison, M., Ed F. Perozzi, Nicole Caran, Jennifer K. Stewart e Robert M. Tombes. "Axonal localization of delta Ca 2+ /calmodulin‐dependent protein kinase II in developing P19 neurons". International Journal of Developmental Neuroscience 20, n.º 8 (dezembro de 2002): 585–92. http://dx.doi.org/10.1016/s0736-5748(02)00107-7.

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Worrell, R. T., e R. A. Frizzell. "CaMKII mediates stimulation of chloride conductance by calcium in T84 cells". American Journal of Physiology-Cell Physiology 260, n.º 4 (1 de abril de 1991): C877—C882. http://dx.doi.org/10.1152/ajpcell.1991.260.4.c877.

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We used the secretory colonic cell line T84 to study the regulatory pathways controlling the Ca-stimulated Cl conductance [GCl(Ca)]. Under whole cell patch clamp, basal (unstimulated) current levels averaged 73 +/- 9 pA/20 pF (n = 93) and increased to 600 +/- 100 pA/20 pF (n = 53; at +100 mV) on exposure to 1-2 microM ionomycin. Bath application of the calmodulin (CaM) antagonists trifluoperazine, calmidazolium, or sphingosine (50 microM) reversibly inhibited GCl(Ca), whereas the protein kinase C antagonists H7 and phloretin (50 microM) were without effect. This suggests that increases in intracellular Ca stimulate GCl(Ca) via a CaM-dependent process rather than activating Cl channels directly. To assess the involvement of protein kinases in the Ca-dependent stimulation of Cl conductance, we employed pseudosubstrate peptide inhibitors of protein kinase C (PKC) and the Ca/CaM-dependent protein kinase II (CaMKII). Cellular concentrations of inhibitors during whole cell recording were estimated to be 4-20 times the inhibitory constant values for kinase inhibition observed in vitro. Pipette solutions containing the PKC peptide inhibitor PKC-(19-36) (7.5 microM) had no effect on GCl(Ca). In contrast, stimulation of GCl(Ca) by ionomycin was abolished when pipette solutions contained 10 microM CaMKII peptide inhibitor CaMKII-(273-302). The truncated peptide CaMKII-(284-302) (20 microM) lacks the CaMKII inhibitory domain and did not affect GCl(Ca). These data suggest that CaM, acting through the multifunctional CaMKII, mediates the Ca-dependent stimulation of Cl conductance in colonic secretory cells.

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Cai, Hua, Michael E. Davis, Grant R. Drummond e David G. Harrison. "Induction of Endothelial NO Synthase by Hydrogen Peroxide via a Ca 2+ /Calmodulin-Dependent Protein Kinase II/Janus Kinase 2–Dependent Pathway". Arteriosclerosis, Thrombosis, and Vascular Biology 21, n.º 10 (outubro de 2001): 1571–76. http://dx.doi.org/10.1161/hq1001.097028.

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Sugiura, Hiroko, e Takashi Yamauci. "Developmental changes of protein substrates of Ca 2+ / calmodulin-dependent protein kinase II in teh rat forebrain". Brain Research 659, n.º 1-2 (outubro de 1994): 42–54. http://dx.doi.org/10.1016/0006-8993(94)90861-3.

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Díaz-Nido, J., L. Serrano, E. Méndez e J. Avila. "A casein kinase II-related activity is involved in phosphorylation of microtubule-associated protein MAP-1B during neuroblastoma cell differentiation." Journal of Cell Biology 106, n.º 6 (1 de junho de 1988): 2057–65. http://dx.doi.org/10.1083/jcb.106.6.2057.

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A neuroblastoma protein related to the brain microtubule-associated protein, MAP-1B, as determined by immunoprecipitation and coassembly with brain microtubules, becomes phosphorylated when N2A mouse neuroblastoma cells are induced to generate microtubule-containing neurites. To characterize the protein kinases that may be involved in this in vivo phosphorylation of MAP-1B, we have studied its in vitro phosphorylation. In brain microtubule protein, MAP-1B appears to be phosphorylated in vitro by an endogenous casein kinase II-like activity which also phosphorylates the related protein MAP-1A but scarcely phosphorylates MAP-2. A similar kinase activity has been detected in cell-free extracts of differentiating N2A cells. Using brain MAP preparations devoid of endogenous kinase activities and different purified protein kinases, we have found that MAP-1B is barely phosphorylated by cAMP-dependent protein kinase, Ca/calmodulin-dependent protein kinase, or Ca/phospholipid-dependent protein kinase whereas MAP-1B is one of the preferred substrates, together with MAP-1A, for casein kinase II. Brain MAP-1B phosphorylated in vitro by casein kinase II efficiently coassembles with microtubule proteins in the same way as in vivo phosphorylated MAP-1B from neuroblastoma cells. Furthermore, the phosphopeptide patterns of brain MAP-1B phosphorylated in vitro by either purified casein kinase II or an extract obtained from differentiating neuroblastoma cells are identical to each other and similar to that of in vivo phosphorylated neuroblastoma MAP-1B. Thus, we suggest that the observed phosphorylation of a protein identified as MAP-1B during neurite outgrowth is mainly due to the activation of a casein kinase II-related activity in differentiating neuroblastoma cells. This kinase activity, previously implicated in beta-tubulin phosphorylation (Serrano, L., J. Díaz-Nido, F. Wandosell, and J. Avila, 1987. J. Cell Biol. 105: 1731-1739), may consequently have an important role in posttranslational modifications of microtubule proteins required for neuronal differentiation.

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Fischer, Thomas H., Jörg Eiringhaus, Nataliya Dybkova, Anna Förster, Jonas Herting, Astrid Kleinwächter, Senka Ljubojevic et al. "Ca 2+ /calmodulin‐dependent protein kinase II equally induces sarcoplasmic reticulum Ca 2+ leak in human ischaemic and dilated cardiomyopathy". European Journal of Heart Failure 16, n.º 12 (8 de setembro de 2014): 1292–300. http://dx.doi.org/10.1002/ejhf.163.

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Ai, Xun, Jerry W. Curran, Thomas R. Shannon, Donald M. Bers e Steven M. Pogwizd. "Ca 2+ /Calmodulin–Dependent Protein Kinase Modulates Cardiac Ryanodine Receptor Phosphorylation and Sarcoplasmic Reticulum Ca 2+ Leak in Heart Failure". Circulation Research 97, n.º 12 (9 de dezembro de 2005): 1314–22. http://dx.doi.org/10.1161/01.res.0000194329.41863.89.

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Nygård, O., A. Nilsson, U. Carlberg, L. Nilsson e R. Amons. "Phosphorylation regulates the activity of the eEF-2-specific Ca(2+)- and calmodulin-dependent protein kinase III." Journal of Biological Chemistry 266, n.º 25 (setembro de 1991): 16425–30. http://dx.doi.org/10.1016/s0021-9258(18)55316-3.

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46

Ho, Hsiang-Ting, Andriy E. Belevych, Bin Liu, Ingrid M. Bonilla, Przemysław B. Radwański, Igor V. Kubasov, Héctor H. Valdivia, Karsten Schober, Cynthia A. Carnes e Sándor Györke. "Muscarinic Stimulation Facilitates Sarcoplasmic Reticulum Ca Release by Modulating Ryanodine Receptor 2 Phosphorylation Through Protein Kinase G and Ca/Calmodulin-Dependent Protein Kinase II". Hypertension 68, n.º 5 (novembro de 2016): 1171–78. http://dx.doi.org/10.1161/hypertensionaha.116.07666.

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47

Bassani, R. A., A. Mattiazzi e D. M. Bers. "CaMKII is responsible for activity-dependent acceleration of relaxation in rat ventricular myocytes". American Journal of Physiology-Heart and Circulatory Physiology 268, n.º 2 (1 de fevereiro de 1995): H703—H712. http://dx.doi.org/10.1152/ajpheart.1995.268.2.h703.

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We investigated the role of Ca/calmodulin-dependent protein kinase (CaMKII) in relaxation and cytosolic free [Ca] ([Ca]i) decline during steady-state (SS) and postrest (PR) twitches in intact rat ventricular myocytes. Half-time of mechanical relaxation and time constant of [Ca]i decline (tau) were twofold greater during PR than with SS at 1 Hz. This difference was 1) abolished by inhibition of sarcoplasmic reticulum (SR) Ca accumulation by thapsigargin or caffeine; 2) greater at higher stimulation frequency and extracellular [Ca], which affected only SS tau; 3) abolished by the protein phosphatase inhibitor okadaic acid (10 microM, which selectively accelerated [Ca]i decline during PR); 4) still present during stimulation or inhibition of adenosine 3',5'-cyclic monophosphate-dependent protein kinase (PKA) by 10 microM forskolin or 1 microM H-89, respectively (SS and PR tau values were abbreviated and prolonged, respectively); and 5) suppressed by 10 microM KN-62, a selective inhibitor of CaMKII, which selectively prolonged [Ca]i decline during SS twitches. Both protein kinase inhibitors were also shown to decrease the SR Ca-uptake rate in digitonin-permeabilized rat myocytes. We conclude that CaMKII plays a major role in modulation of relaxation in rat ventricular myocytes, enhancing SR Ca uptake in a activity-dependent fashion. Our results are also compatible with a background, activity-independent stimulation of SR Ca uptake by PKA in intact rat myocytes.

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Foster, RH. "Reciprocal influences between the signalling pathways regulating proliferation and steroidogenesis in adrenal glomerulosa cells". Journal of Molecular Endocrinology 32, n.º 3 (1 de junho de 2004): 893–902. http://dx.doi.org/10.1677/jme.0.0320893.

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The main regulators of aldosterone secretion in adrenal gland zona glomerulosa (ZG) cells are the hormones angiotensin II (Ang II) and adrenocorticotrophin (ACTH) and small increases in the extracellular potassium (K(+)) concentration. The action of these agonists is mediated by different signalling systems - ACTH is mediated by cAMP and activation of protein kinase A while Ang II and K(+) activate two protein kinases, Ca(2+)-calmodulin-dependent protein kinase (CamK) and diacylglycerol-dependent protein kinase (PKC). Ang II, besides being one of the main agonists for the secretion of aldosterone, also stimulates proliferation of ZG cells, a process mediated by mitogen-activated protein kinases (MAPKs). Recent studies aimed at elucidating the molecular mechanisms underlying cell proliferation have shown that calcineurin is the principal regulator of MAPKs activity. The purpose of this review is to discuss experimental evidence of possible reciprocal influences between the signalling pathways regulating proliferation and steroidogenesis in ZG cells.

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Ichikawa, K. "3P260 Localization of Activated Ca^<2+>/calmodulin-Dependent Protein kinase II within a spine". Seibutsu Butsuri 45, supplement (2005): S268. http://dx.doi.org/10.2142/biophys.45.s268_4.

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Atala, Anthony. "Re: Ca 2+ /Calmodulin-Dependent Protein Kinase II is Associated with Pelvic Pain of Neurogenic Cystitis". Journal of Urology 189, n.º 3 (março de 2013): 1162. http://dx.doi.org/10.1016/j.juro.2012.11.124.

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