Log in

Relevant bibliographies by topics / Calcium/calmodulin-dependent protein kinase II / Dissertations / Theses

To see the other types of publications on this topic, follow the link: Calcium/calmodulin-dependent protein kinase II.

Dissertations / Theses on the topic 'Calcium/calmodulin-dependent protein kinase II'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Calcium/calmodulin-dependent protein kinase II.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Saeedi, Shahriar. "Targeting of calcium/calmodulin-dependent protein kinase II to membranes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ57789.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Saeedi, Shahriar Carleton University Dissertation Biology. "Targeting of calcium/calmodulin-dependent protein kinase II to membranes." Ottawa, 2000.

Find full text

APA, Harvard, Vancouver, ISO, and other styles

3

He, Beixin Julie. "Calcium and calmodulin dependent protein kinase II hyperactivity in cardiac remodeling." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/2516.

Full text

Abstract:

The multifunctional calcium and calmodulin dependent protein kinase II (CaMKII) is implicated in both animal models and human forms of cardiovascular disease. CaMKII is activated by elevated neurohormonal signals including enhanced â-adrenergic stimulation and angiotensin II signaling, whereas CaMKII inhibition is cardioprotective from these pathologic triggers. In addition to â-blockers and angiotensin II inhibitors, aldosterone antagonist drugs are the third and most recent class of pharmacologic agents comprising the frontline therapy for heart disease patients. Here, I show that CaMKII activation is important for cardiac aldosterone signaling in the post-myocardial infarction (MI) mouse model. Aldosterone infusion to MI mice increases cardiac rupture, a lethal and nearly untreatable clinical problem. CaMKII inhibition protects from aldosterone enhanced post-MI rupture. We previously reported microarray analysis of genes upregulated after MI but downregulated in the presence of cardiac CaMKII inhibition. Surprisingly, a number of these genes are involved in extracellular matrix remodeling. Here, I validated the microarray findings for matrix metalloproteinase 9 (MMP9), an extracellular matrix remodeling enzyme known to contribute to the rupture phenotype. My results support a sequence where aldosterone infusion after MI recruits NADPH oxidase-derived reactive oxygen species to enhance CaMKII oxidation and subsequent myocyte enhancer factor 2 driven increases in MMP9 expression in myocytes. I found that oxidative activation of CaMKII is critical for this rupture phenotype through a new transgenic mouse model that overexpresses methionine sulfoxide reductase A, which modulates CaMKII oxidation and therefore activation. These results implicate CaMKII activation in cardiac aldosterone signaling and reinforce the importance of CaMKII hyperactivity in acute cardiac remodeling after MI. Overall, this work supports myocardial CaMKII as a novel mediator of cardiac aldosterone stimulation of post-MI matrix remodeling and suggests potential efficacy for molecularly targeted anti-oxidant therapy in the treatment of patients after acute MI.

APA, Harvard, Vancouver, ISO, and other styles

4

Jama, Abdirahman Mohamud. "Functional regulation of kisspeptin receptor by calmodulin and Ca2+/calmodulin-dependent protein kinase II." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/15914.

Full text

Abstract:

The kisspeptin receptor (KISS1R), functioning as a metastasis suppressor and gatekeeper of GnRH neurons, is a potent activator of intracellular Ca2+. The surge in cytoplasmic Ca2+ mediates the exocytosis of GnRH from GnRH neurons. However, the regulatory processes which enable KISS1R to sense increasing intracellular Ca2+ and avoid Ca2+ excitotoxicity via a signalling off-switch mechanism remain unclear. This thesis provides evidence for the interaction between KISS1R and the Ca2+ regulated proteins of calmodulin (CaM), and αCa2+/CaM-dependent-protein kinase II (α-CaMKII). Binding of CaM to KISS1R was shown with three independent approaches. Firstly, cell-free spectrofluorimeter assays showed that CaM selectively binds to intracellular loop (IL) 2 and IL3 of the KISS1R. Secondly, KISS1R co-immunoprecipitation experiments identified ligand/Ca2+-dependent binding of KISS1R to HEK-293 endogenous CaM. Thirdly, confocal experiments showed CFPCaM co-localises with YFP-KISS1R. The functional relevance of CaM binding was examined with alanine substitution of critical residues of the CaM binding motifs in IL2 and IL3 of KISS1R. This approach revealed that the receptor activity (relative maximum responsiveness) was increased in the mutated residues of the juxtamembrane regions of IL3 and the N-terminus of IL2 relative to wild-type KISS1R. The Ca2+/CaM regulated αCaMKII was also found to interact with KISS1R by selectively phosphorylating T77 of IL1. Phosphomimetic mutations of T77 into E or D created a receptor that was unable to elicit inositol phosphate production upon ligand stimulation. Finally, in vivo studies using ovariectomised rats that were intracerebroventricularly administered with a cell-permeable αCaMKII inhibitor augmented the effects of kisspeptin ligand stimulation of plasma luteinizing hormone levels. Taken together, this thesis demonstrates that the KISS1R-G protein coupling is regulated by Ca2+-dependent CaM binding and αCaMKII-mediated KISS1R phosphorylation.

APA, Harvard, Vancouver, ISO, and other styles

5

BEAUMAN, SHIRELYN RAE. "THE FUNCTION OF CALCIUM/CALMODULIN DEPENDENT PROTEIN KINASE II IN CELL CYCLE REGULATION." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1054300335.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Novak, Gabriela. "Schizophrenia, elevated mRNA for calcium/calmodulin-dependent protein kinase II ß in frontal cortex." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63175.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Haus, Jacob M. "AMP-activated protein kinase (AMPK) and calcium/calmodulin-dependent protein kinase II (CAMKII) activation in exercising human skeletal muscle." Virtual Press, 2004. http://liblink.bsu.edu/uhtbin/catkey/1294245.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Wenham, Robert M. (Robert Michael). "Evidence for a role of the multifunctional calcium/calmodulin-dependent protein kinase II in insulin secretion." Thesis, North Texas State University, 1993. https://digital.library.unt.edu/ark:/67531/metadc798159/.

Full text

Abstract:

Calcium/calmodulin-dependent protein kinase II (CaM kinase II) is demonstrated to exist in the ß-cell and immunopecipitation. Glucose and potassium significantly stimulate the rapid autophosphorylation of CaM kinase II and proportionally induce autonomous activity of the kinase in a dose-dependent manner that parallels insulin secretion. The activation of CaM kinase II, alloxan, KN-62 and KN-93, suggest that the enzyme is an integral component of insulin secretion and/or related processes in the β-cell.

APA, Harvard, Vancouver, ISO, and other styles

9

Breen, Maria Adrienne. "Molecular characterisation of the calcium/calmodulin-dependent protein kinase II of human islets of Langerhans." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337543.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Mooney, Laura. "Development of a small animal of cardiac contractility and calcium/calmodulin-dependent protein kinase II." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=18577.

Full text

Abstract:

Several drugs in development or on the market have adverse effects on cardiac contractility. Calcium/calmodulin-dependent protein kinase IIδ (CaMKIIδ) is an important regulator of cardiac contractility with a particularly prominent role in pathophysiological conditions where contractile dysfunction occurs. Therefore, CaMKIIδ may be an intracellular target for drugs that alter cardiac performance. The aim of the work presented in this thesis was to develop a small animal model for the integrated assessment of cardiac contractility and CaMKII. An anaesthetised guinea pig model was developed to assess haemodynamics and cardiac contractility via two indices - left ventricular (LV) dP/dtmax and the QA interval. Acute administration of isoprenaline and ouabain increased contractility whilst verapamil, imatinib and sunitinib decreased contractility. There was a strong inverse correlation between LVdP/dtmax and the QA interval. CaMKIIδ expression and CaMKII activity were not significantly altered by any acute drug treatment. Both LVdP/dtmax and the QA interval were influenced by changes in blood pressure. Additionally, LVdP/dtmax was influenced by changes in heart rate. Measurement of contractility via LV pressure-volume loops was also assessed. Surgical approaches and recordings were optimised and isoprenaline and verapamil had positive and negative inotropic actions, respectively. Several issues were identified which require further attention. Chronic administration of isoprenaline and verapamil decreased cardiac contractility and increased CaMKIIδ expression and CaMKII activity. Chronic imatinib and sunitinib treatments did not alter cardiac contractility significantly. However, both CaMKIIδ expression and CaMKII activity were increased. The work presented in this thesis indicates that the guinea pig is suitable for the integrated assessment of cardiac contractility and CaMKII. Alterations in CaMKIIδ expression and CaMKII activity following chronic drug treatments could be an indication of cellular cardiotoxicity associated with contractile dysfunction at the whole animal level. The circumstances under which increased CaMKII expression and activity translate to compromised contractile performance require more detailed investigation.

APA, Harvard, Vancouver, ISO, and other styles

11

Waggener, Christopher. "Calcium/Calmodulin-Dependent Protein Kinase II Beta (CaMKIIβ): A Regulator of Oligodendrocyte Maturation and Myelination." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/527.

Full text

Abstract:

Oligodendrocytes are cells located in the central nervous system (CNS) that are responsible for the production of the lipid rich membrane, myelin. Myelin and the process of making and wrapping myelin around an axon (also known as myelination) are critical for normal development since they ensure proper signal conduction in the vertebrate CNS. The loss or damage of this myelin, which is typically associated with the demyelinating disease multiple sclerosis (MS), is associated with improper axonal protection along with disrupted nerve signaling which can lead to a variety of different debilitating phenotypic responses. It has been shown that there are MS lesions in which oligodendrocyte progenitors are present. However, while these cells are thought to possess the intrinsic ability to myelinate, they do not efficiently mature and/or repair the myelin sheath within the MS lesion. The reasons for this block in differentiation are currently not fully understood. A critical and thorough understanding of oligodendrocyte ix development provides the foundation needed for future research to potentially provide therapeutic targets for stimulating proper maturation and efficient remyelination from the oligodendrocyte progenitors that are present within the MS brain. In the search for regulators of oligodendrocyte development and potential therapeutic targets, the data generated as part of my thesis provided evidence that CaMKII (more specifically CaMKIIβ) is a regulator of oligodendrocyte myelination and maturation. Using pharmacological inhibitors or siRNA-mediated knockdown of this protein resulted in improper formation of the oligodendrocyte process network. Interestingly, siRNA-mediated knockdown of CaMKIIβ appeared to play no noticeable role in the genetic regulation of specific oligodendrocyte developmental markers. Furthermore, an overall reduction of the thickness of the compact myelin was observed in the ventral spinal cord of CaMKIIβ knockout mice. These findings emphasize the importance of CaMKIIβ in oligodendrocyte myelination and maturation. To further investigate CaMKIIβ’s role in the regulation of CNS myelination, the effect of glutamate signaling on CaMKIIβ and in particular its actin binding site were assessed. These data showed that signaling via glutamate transporters promote an increase of process network in oligodendrocytes. This effect was associated with a transient increase in intracellular calcium concentration and a change in the phosphorylation of at least one serine residue present within CaMKIIβ’s actin binding site. Changes in phosphorylation of CaMKIIβ’s actin binding site suggested that CaMKIIβ detaches from filamentous F-actin and x allows for remodeling of the oligodendrocyte’s actin cytoskeleton. This was demonstrated by overexpressing CaMKIIβ actin binding mutant constructs to alter phosphorylation of serine residues to either always allow actin binding (CaMKIIβallA) or never allow actin binding (CaMKIIβallD). The overexpression of CaMKIIβallD alone demonstrated a decrease in the process network of oligodendrocytes and inhibited the effect of glutamate on the process network. In contrast, the overexpression of CaMKIIβallA and CaMKIIβWT alone showed normal process network formation along with a significant increase in the process network after stimulation of glutamate. The above data strongly suggest that there is a significant relationship between sodium dependent glutamate transporters/CaMKIIβ activation and the oligodendrocyte cytoskeleton in the role of regulation of oligodendrocyte differentiation and CNS myelination. The data presented in this dissertation provides overwhelming evidence that CaMKIIβ plays a significant role in the proper formation of the oligodendrocyte complex process network and myelination. CaMKIIβ’s relationship with glutamate and the actin cytoskeleton could lay the foundation for future research not only for the signaling of oligodendrocyte process formation and remyelination but also for future targets for MS therapies.

APA, Harvard, Vancouver, ISO, and other styles

12

Chatzis, George J. "Biochemical properties of the muscle-specific calcium(2+)/calmodulin-dependent protein kinase II beta isoform." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9357.

Full text

Abstract:

Cytosolic calcium (Ca2+) levels are critical for the control of muscle contraction and are tightly regulated by a variety of Ca 2+ transport systems localized in various membranes. Ca2+ binding proteins such as calmodulin (CaM) and Ca2+/CaM-dependent protein kinases (CaM Kinases) are believed to exert major regulatory control on Ca2+ activity. Previous studies in this lab led to the cloning of a cDNA encoding a CaM Kinase II beta isoform from skeletal muscle that differed from the classical beta isoform by the inclusion of three alternatively spliced exons in the variable domain which were enriched in proline residues. A CaM Kinase, assumed to be localized in the sarcoplasmic reticulum (SR), has been implicated in the regulation of excitation-contraction (E-C) coupling. We hypothesized that this novel CaM Kinase II beta isoform called SOCK (Son Of CaM Kinase) may be the CaM Kinase II isoform that regulates E-C coupling by being targeted to specific regions of the SR, whereby it phosphorylates critical Ca2+ transporting proteins such as the ryanodine (RyR) and dihydropyridine (DHPR) receptors in response to changes in Ca2+ levels. (Abstract shortened by UMI.)

APA, Harvard, Vancouver, ISO, and other styles

13

Ma, Yan. "Role of the Ca2+ / calmodulin-dependent protein kinase II pathway in the cardioprotective effect of estrogen." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41290744.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Seward, Matthew Edward. "Calcium/Calmodulin Dependent Protein Kinase Type-II Associates with Flightless-I to Influence its Nuclear Localization." VCU Scholars Compass, 2006. http://hdl.handle.net/10156/2132.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Ma, Yan, and 馬妍. "Role of the Ca2+ / calmodulin-dependent protein kinase II pathway in the cardioprotective effect of estrogen." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41290744.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Fick, Christopher A. "The effect of calcium-dependent calmodulin protein kinase II (CAMKII) inhibition on insulin stimulated glucose transport in fast-twitch muscle." Virtual Press, 2002. http://liblink.bsu.edu/uhtbin/catkey/1233194.

Full text

Abstract:

Insulin stimulates glucose transport into muscle cells and adipocytes via a process that involves the translocation of GLUT4 proteins from intracellular stores to the cell membrane. The pathway by which this translocation takes place has not been fully elucidated. The purpose of this study was to determine the effect of the calciumdependent calmodulin protein kinase II (CAMKII) inhibitor KN-62 on insulin stimulated 3-0-methylglucose transport in isolated rat epitrochlearis muscles. The primary finding of this investigation was that KN-62 decreased insulin stimulated glucose transport by -35%. KN-04, a structural analogue of KN-62, did not affect insulin stimulated glucose transport. Additional experiments showed that the L-type calcium (Ca 2+) channel inhibitor nifedipine inhibited glucose transport to a similar extent as KN-62 (-29%). Furthermore, no additive inhibitory effect was seen when KN-62 and nifedipine were used in combination. The results of this investigation suggest that CAMKII has a critical role in insulin stimulated glucose transport, and this role may be dependent upon L-type Cat- channel activation.
School of Physical Education

APA, Harvard, Vancouver, ISO, and other styles

17

Easley, Charles Allen. "Fibronectin-dependent activation of CaMK-II promotes focal adhesion disassembly by inducing tyrosine dephosphorylation of FAK and paxillin /." Unavailable until 8/19/2013, 2008. http://hdl.handle.net/10156/2272.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Lau, Faye. "Muscular activity regulates the expression of ColQ subunit of acetylcholinesterase : a signaling pathway mediated by Ca2̳+̳/ calmodulin-dependent protein kinase II /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202007%20LAU.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Lin, Kim-fung. "Evaluation of calcium/calmodulin kinase II as therapeutic target in beta-amyloid peptide neurotoxicity." Thesis, Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B3145253X.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Wicks, Stephen John. "Inactivation of the TGF-/Smad signalling pathway by calcium/calmodulin protein kinase II." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411236.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Akintürk, Sulhiye Serra [Verfasser], Rolf [Gutachter] Dermietzel, and Michael [Gutachter] Hollmann. "Interaction of the neuronal gap junction protein Connexin 36 with alpha Calcium/Calmodulin-dependent protein Kinase II / Sulhiye Serra Akintürk ; Gutachter: Rolf Dermietzel, Michael Hollmann." Bochum : Ruhr-Universität Bochum, 2013. http://d-nb.info/1131354621/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Marshall, Maria Nieves Martinez. "The role of the LAMMER kinase Kns1 and the calcium/calmodulin-dependent kinase Cmk2 in the adaptation of Saccharomyces cerevisiae to alkaline pH stress." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16663.

Full text

Abstract:

Die LAMMER-Kinasen sind Dual-Spezifität-Proteinkinasen, die durch das namensgebende einzigartige LAMMER-Motiv gekennzeichnet sind. Sie sind evolutionär hoch konserviert und in den meisten Eukaryonten vorhanden. Die vorliegende Arbeit stellt die erste funktionelle Charakterisierung eines bisher kaum erforschten Vertreters der LAMMER-Proteinkinase Familie Kns1 aus der Bäckerhefe dar. Phänotypische Analysen belegten eine entscheidende Rolle für Kns1 in der Regulation der Toleranz gegenüber basischem pH-Stress. Das Entfernen des KNS1 Gens führte zu einer gesteigerten Empfindlichkeit der Zellen gegenüber basischen Wachstumsbedingungen. Weitere Analysen zeigten, dass Kns1 neben der katalytischen Aktivität auch nicht-katalytischen Mechanismen zur Förderung des Zellwachstums unter alkalischem pH-Stress nutzt. Die Reinigung des Kns1 Proteins in voller Länge aus E. coli ermöglichte die Identifizierung von neun in vitro-Autophosphorylierungsstellen mittels Massenspektrometrie. Die Mutation von Thr562, eine Autophosphorylierungsstelle innerhalb des LAMMER-Motivs, zu Alanin ergab in vitro eine Kinase mit intrinsischer katalytischer Aktivität, die sich jedoch in vivo hauptsächlich wie die katalytisch inaktive Kns1-Mutante verhielt. Die Calcium/Calmodulin-abhängige Proteinkinase II Cmk2, die konstitutiv autokatalytische Eigenschaften besitzt, wurde früher als mögliches in vitro Substrat von Kns1 vorgeschlagen. In dieser Arbeit beweise ich durch Verwendung einer katalytisch inaktiven Cmk2-Mutante als Substrat, dass Kns1 Cmk2 in vitro phosphoryliert. Darüber hinaus zeige ich, dass Cmk2 die basische pH-Toleranz der Zellen beschränkt. Gestützt durch genetische Hinweise agieren beide Proteine gemeinsam bei der Regulation der alkalischen Stresstoleranz, wobei Kns1 möglicherweise Cmk2 herabreguliert. Zusammenfassend beschreibt diese Arbeit eine neue und entscheidende Rolle von Kns1 und Cmk2 bei der Anpassung der Hefe an alkalisches Milieu.
The LAMMER protein kinases, termed after a unique signature motif found in their catalytic domains, are an evolutionary conserved family of dual-specificity kinases that are present in most eukaryotes. Here I report the first functional characterization of one of the most unexplored members of the LAMMER family, the budding yeast Kns1. Phenotypic analysis uncovered a crucial role for Kns1 in the control of the yeast tolerance to high pH stress. Deletion of the KNS1 gene conferred high sensitivity to alkaline pH, whereas its overexpression increased tolerance to this stress. Further analysis established that Kns1 promotes growth under alkaline pH stress using not only its catalytic activity but also non-catalytic mechanisms. Large-scale purification of full-length Kns1 from E. coli allowed for the identification of nine in vitro autophosphorylation sites on Kns1 by mass spectrometry. Mutation of the threonine residue at position 562, an autophosphorylation site located within the LAMMER motif, to a non-phosphorylatable residue yielded a kinase that preserves intrinsic catalytic activity in vitro but mostly behaves like the catalytically inactive mutant in vivo. This finding showed the physiological importance of autophosphorylation site Thr562 in the regulation of Kns1 function. The protein Cmk2, a calcium/calmodulin-dependent protein kinase II with autocatalytic properties, has been previously proposed as a possible in vitro substrate for Kns1. Here I demonstrate that Kns1 phosphorylates Cmk2 in vitro using a catalytically inactive Cmk2 mutant as substrate and show that Cmk2 restricts alkaline tolerance. Genetic evidence suggested that both proteins act in concert on a common pathway, in which Kns1 may downregulate Cmk2 to confer alkaline tolerance. In conclusion, this thesis describes a novel and crucial role for Kns1 and its in vitro substrate Cmk2 in the adaptation of yeast to alkaline stress.

APA, Harvard, Vancouver, ISO, and other styles

23

Chand, Annisa Natalie. "Developmental expression and functional requirements of pituitary guanylyl cyclase-B (GC-B) and calcium/calmodulin-dependent protein kinase II (CaMKII) in vivo and in vitro." Thesis, Royal Veterinary College (University of London), 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558959.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Rothschild, Sarah. "The Role of the Ca2+-dependent protein kinase, CaMK-II, in Heart and Kidney Development in the Zebrafish, Danio rerio." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/60.

Full text

Abstract:

Ca2+/calmodulin-dependent protein kinase type II (CaMK-II) is a multifunctional serine/threonine kinase that is ubiquitously expressed throughout the lifespan of metazoans. Mammals encode four genes (α, β, γ, δ) that generate over forty splice-variants. CaMK-II is important in a myriad of functions, including ion channel regulation, cell-cycle progression, and long term potentiation. In adults, alterations in activation of CaMK-II induce cardiac arrhythmias and heart failure. Developmental roles for CaMK-II are not as well understood since mouse knockouts are embryonic lethal. Therefore the identification of other vertebrate CaMK-II genes will add to our understanding of development. Zebrafish encode seven catalytically active CaMK-II genes (α1, β1, β2, γ1, γ2, δ1, δ2) due to a genome wide duplication event that occurred approximately 250 million years ago. Although, only 20-30% of all duplicated genes were retained, 75% of CaMK-II duplicated genes are transcriptionally active, pointing to a critical role for this signaling protein. mRNA expression patterns demonstrate that CaMK-II is expressed in diverse tissues including retina, pectoral fins, somites, heart, and kidney. Suppression of each gene generates unique phenotypes that mirror the mRNA expression patterns. Of the seven genes, camk2b2 and camk2g1 have the highest maternal contribution in zebrafish, are expressed in mesodermally derived organs, and develop defects similar to human syndromes. In fact, suppression of camk2b2 mimics the phenotype observed in zebrafish mutants of tbx5, the gene mutated in patients with Holt-Oram Syndrome. Camk2g1 morphants also exhibit similar defects as suppression of pkd2, the gene mutated in patients with Autosomal Dominant Polycystic Kidney disease. These roles implicate CaMK-II as an integral protein in the development and maintenance of mesodermally derived tissues.

APA, Harvard, Vancouver, ISO, and other styles

25

Graupner, Michael. "Induction and Maintenance of Synaptic Plasticity." Doctoral thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A23857.

Full text

Abstract:

Synaptic long-term modifications following neuronal activation are believed to be at the origin of learning and long-term memory. Recent experiments suggest that these long-term synaptic changes are all-or-none switch-like events between discrete states of a single synapse. The biochemical network involving calcium/calmodulin-dependent protein kinase II (CaMKII) and its regulating protein signaling cascade has been hypothesized to durably maintain the synaptic state in form of a bistable switch. Furthermore, it has been shown experimentally that CaMKII and associated proteins such as protein kinase A and calcineurin are necessary for the induction of long-lasting increases (long-term potentiation, LTP) and/or long-lasting decreases (long-term depression, LTD) of synaptic efficacy. However, the biochemical mechanisms by which experimental LTP/LTD protocols lead to corresponding transitions between the two states in realistic models of such networks are still unknown. We present a detailed biochemical model of the calcium/calmodulin-dependent autophosphorylation of CaMKII and the protein signaling cascade governing the dephosphorylation of CaMKII. As previously shown, two stable states of the CaMKII phosphorylation level exist at resting intracellular calcium concentrations. Repetitive high calcium levels switch the system from a weakly- to a highly phosphorylated state (LTP). We show that the reverse transition (LTD) can be mediated by elevated phosphatase activity at intermediate calcium levels. It is shown that the CaMKII kinase-phosphatase system can qualitatively reproduce plasticity results in response to spike-timing dependent plasticity (STDP) and presynaptic stimulation protocols. A reduced model based on the CaMKII system is used to elucidate which parameters control the synaptic plasticity outcomes in response to STDP protocols, and in particular how the plasticity results depend on the differential activation of phosphatase and kinase pathways and the level of noise in the calcium transients. Our results show that the protein network including CaMKII can account for (i) induction - through LTP/LTD-like transitions - and (ii) storage - due to its bistability - of synaptic changes. The model allows to link biochemical properties of the synapse with phenomenological 'learning rules' used by theoreticians in neural network studies.

APA, Harvard, Vancouver, ISO, and other styles

26

Graupner, Michael. "Induction and Maintenance of Synaptic Plasticity." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1221145787153-31869.

Full text

Abstract:

Synaptic long-term modifications following neuronal activation are believed to be at the origin of learning and long-term memory. Recent experiments suggest that these long-term synaptic changes are all-or-none switch-like events between discrete states of a single synapse. The biochemical network involving calcium/calmodulin-dependent protein kinase II (CaMKII) and its regulating protein signaling cascade has been hypothesized to durably maintain the synaptic state in form of a bistable switch. Furthermore, it has been shown experimentally that CaMKII and associated proteins such as protein kinase A and calcineurin are necessary for the induction of long-lasting increases (long-term potentiation, LTP) and/or long-lasting decreases (long-term depression, LTD) of synaptic efficacy. However, the biochemical mechanisms by which experimental LTP/LTD protocols lead to corresponding transitions between the two states in realistic models of such networks are still unknown. We present a detailed biochemical model of the calcium/calmodulin-dependent autophosphorylation of CaMKII and the protein signaling cascade governing the dephosphorylation of CaMKII. As previously shown, two stable states of the CaMKII phosphorylation level exist at resting intracellular calcium concentrations. Repetitive high calcium levels switch the system from a weakly- to a highly phosphorylated state (LTP). We show that the reverse transition (LTD) can be mediated by elevated phosphatase activity at intermediate calcium levels. It is shown that the CaMKII kinase-phosphatase system can qualitatively reproduce plasticity results in response to spike-timing dependent plasticity (STDP) and presynaptic stimulation protocols. A reduced model based on the CaMKII system is used to elucidate which parameters control the synaptic plasticity outcomes in response to STDP protocols, and in particular how the plasticity results depend on the differential activation of phosphatase and kinase pathways and the level of noise in the calcium transients. Our results show that the protein network including CaMKII can account for (i) induction - through LTP/LTD-like transitions - and (ii) storage - due to its bistability - of synaptic changes. The model allows to link biochemical properties of the synapse with phenomenological 'learning rules' used by theoreticians in neural network studies.

APA, Harvard, Vancouver, ISO, and other styles

27

Samuels, Emile Rasheed. "Calcium²§+-PS-dependent protein kinase C activity in fetal, neonate and adult rabbit lung and the release of surfactant-related material from isolated fetal rabbit type II alveolar cells." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq23487.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Whelan, Helen A. "Calmodulin Dependent Protein Kinase II - A Sulfhydryl Chemistry Study /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu148793151262033.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Tzortzopoulos, Athanasios. "Activation mechanism of a-CaÂ²+/calmodulin-dependent protein kinase II." Thesis, St George's, University of London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252397.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Folkerts, Michael Matthew. "Autophosphorylation of calcium/calmodulin-dependent kinase II (CaMKII) after traumatic brain injury /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Kwiatkowski, Ann Phyllis. "Structure, function, and regulation of type II calmodulin dependent protein kinase /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487596807822769.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Takeuchi-Suzuki, Erika. "Structure, function, and regulation of type II calmodulin-dependent protein kinase /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487846885779386.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Penfold, Lucy. "Investigating the roles of AMP-activated protein kinase and calcium/calmodulin-dependent protein kinase kinase β in prostate cancer." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/54390.

Full text

Abstract:

Prostate cancer cells are characterised by rapid growth, proliferation and migration, which requires rewiring of cellular metabolism including increased lipid and protein synthesis. AMP-activated protein kinase (AMPK) is a conserved master regulator of energy homeostasis and acts to downregulate anabolism and cell growth, whilst upregulating catabolism to maintain cellular ATP levels. Whether these actions inhibit or aid cancer progression is controversial. Intriguingly, an upstream activating kinase of AMPK, calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ) has recently been implicated in prostate cancer progression. A small-molecule direct activator of AMPK, 991, was used to test the effects of AMPK activation in a panel of prostate cancer cell lines. AMPK activation led to downregulation of cellular proliferation, 2D migration, invasion and lipogenesis, and upregulation of adhesion in all cell lines. However, in PC3 and 22RV1 cells AMPK activation led to an increase in migration down a chemoattractant gradient. This increase in migration was dependent on CaMKKβ and PAK1 activity. To investigate the role of AMPK and CaMKKβ in vivo the PTEN prostate cancer mouse model was used. AMPKβ1 and CaMKKβ were deleted in this model creating two novel mouse lines. Upon β1-deletion prostate cancer development was increased based on the timing of a switch in protein expression characterised in the PTEN-/- prostate upon disease progression and pathological analysis of tissue sections. In contrast, disease progression was significantly reduced upon CaMKKβ-deletion in the PTEN-/- prostate based on prostate weight, Ki-67 staining and pathological analysis. Disease progression was also inhibited in the PTEN mouse model upon treatment with a pharmacological inhibitor of CaMKKβ, STO609. These data suggest that AMPK and CaMKKβ have different roles in prostate cancer development and progression likely lie on separate pathways in this disease.

APA, Harvard, Vancouver, ISO, and other styles

34

Borges, Vigil Fabio Antonio. "The roles of endogenous calcium/calmodulin-dependent kinase II inhibitors in learning and memory." Thesis, King's College London (University of London), 2015. http://kclpure.kcl.ac.uk/portal/en/theses/the-roles-of-endogenous-calciumcalmodulindependent-kinase-ii-inhibitors-in-learning-and-memory(3da1a6e8-261b-4ab5-b63d-3555f01aefef).html.

Full text

Abstract:

Calcium/Calmodulin-dependent kinase II (CaMKII) is a serine/threonine kinase with a wide range of substrates. A number of studies have established that CaMKII is fundamentally important for various learning and memory processes. Given this importance the activity of CaMKII must be tightly regulated. Two endogenous inhibitor proteins of CaMKII, CaMK2N1 and CaMK2N2, have been identified. During contextual fear memory formation CaMK2N1 and CaMK2N2 expression increases in brain regions that are related to the task. However, the functions of CaMK2Ns are still unknown. Our aim was to study the physiological roles of these inhibitors in memory and learning. For that purpose we used adeno-associated virus vector to either knockdown the expression of CaMK2N1 or overexpress CaMK2N2 in the dorsal hippocampus of mice. Animals were trained and tested in contextual fear conditioning paradigm. The knockdown of CaMK2N1 expression had no effect on long-term memory formation, but it impaired long-term memory maintenance after retrieval. Western blot analyses revealed that CaMK2N1 knockdown prevents a decrease in T286 phosphorylation of αCaMKII induced by memory testing, as well as a reduction of GluA1 and c-fos levels. This puts forward the hypothesis that CaMK2N1 is necessary for inducing a decrease in neuronal activation after memory retrieval and that this process is required for memory maintenance. Regarding the hippocampal overexpression of CaMK2N2, treatment prior to training blocked contextual memory formation. On the other hand, overexpression of the same inhibitor after training had no effect on contextual long-term memory maintenance. These results support the view persistent CaMKII activity is not the molecular basis of long-term memory maintenance but its inhibition is.

APA, Harvard, Vancouver, ISO, and other styles

35

Zhou, Zhihong Lucy. "Molecular cloning and characterization of novel isoforms of calmodulin-dependent protein kinase II." Case Western Reserve University School of Graduate Studies / OhioLINK, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1057945686.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Choo, Hyeran. "Ca²⁺/calmodulin-dependent protein kinase II regulates the growth of human osteosarcoma cells in vivo." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2007. http://www.mhsl.uab.edu/dt/2007m/choo.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Kurtz, Camden E. "Ca2+/calmodulin-dependent protein kinase type II (CaMK-II) is required for hematopoietic stem cell specification." VCU Scholars Compass, 2017. https://scholarscompass.vcu.edu/etd/5202.

Full text

Abstract:

Ca2+/Calmodulin-dependent protein kinase type II (CaMK-II) is a Serine/Threonine protein kinase that is activated by Ca2+ and Calmodulin to phosphorylate substrates involved in myriad developmental processes. This project implicates CaMK-II in specification of HSCs, and zebrafish provide an ideal embryonic model to study hematopoiesis. Zebrafish genetic manipulation was achieved through: incubation in chemical inhibitors; injection of notochord-targed WT and DN CaMK-II constructs with Transposase; and injection of camk2g1 translation-blocking morpholino antisense oligonucleotide (MO). Whole-mount in situ hybridization (WISH) and immunolocalization on zebrafish embryos allowed visualization of key HSC markers and pathway components that implicated CaMK-II in the specification of HSCs. CaMK-II is a negative regulator of shh expression during HSC specification, but CaMK-II does not influence Shh during its well-documented role in vasculogenesis. CaMK-II appears to affect the spatial distribution of Shh protein, which accumulates near the notochord source and differentially affects expression of Shh target genes based on their distance from the notochord. This project also identifies the specific timing requirement for CaMK-II during HSC specification, as inhibition of CaMK-II consistently reduces HSC specification, but only if administered before 18hpf. CaMK-II also downregulates ezh2 in the DA during the time of HSC specification, and the Ezh2 inhibition rescues the loss of HSCs, suggesting that CaMK-II regulates the secretion of Shh from the notochord to epigenetically regulate expression of key HSC specification genes in the DA through EZH2 methyltransferase.

APA, Harvard, Vancouver, ISO, and other styles

38

Molloy, Sean S. Kennedy Mary B. Kennedy Mary B. "A study of the type II CA2+/calmodulin-dependent protein kinase on hippocampal neurons /." Diss., Pasadena, Calif. : California Institute of Technology, 1991. http://resolver.caltech.edu/CaltechETD:etd-08232007-130039.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Kutcher, III Louis Wm. "The importance of subcellular localization of Ca2⁺/calmodulin dependent protein kinase II in neuronal differentiation." Cincinnati, Ohio : University of Cincinnati, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1046711125.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

KUTCHER, LOUIS WM III. "THE IMPORTANCE OF SUBCELLULAR LOCALIZATION OF CA2+/CALMODULIN DEPENDENT PROTEIN KINASE II IN NEURONAL DIFFERENTIATION." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1046711125.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

McNeil, Melissa Ann. "Calcium Signaling and Ca²⁺/Calmodulin-Dependent Kinase II Activity in Epithelial To Mesenchymal Transition." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/6147.

Full text

Abstract:

Epithelial to mesenchymal transition (EMT) is an important process in embryonic development, tissue repair, inflammation, and cancer. During EMT, epithelial cells disassemble cell-cell adhesions, lose apicobasal polarity, and initiate migratory and invasive processes that allow individual cells to colonize distant sites. It is the means by which non-invasive tumors progress into malignant, metastatic carcinomas. In vitro, EMT occurs in two steps. First, cells spread out, increasing in surface area and pushing the colony borders out. Then cells contract, pulling away from neighboring cells and rupturing cell-cell junctions, resulting in individual highly migratory cells. Recent discoveries indicate that calcium signaling is central in EMT. Both previous data with patch clamping and new calcium imaging data show a series of calcium influxes in cells induced to undergo EMT with hepatocyte growth factor (HGF). It has also been shown that blocking calcium signaling prevents EMT from progressing normally. However, it is not known if calcium alone is sufficient to drive EMT behaviors. By experimentally triggering calcium influxes with an optigenetic cation channel, the behaviors that calcium influxes induce can be determined noninvasively, without use of drugs that may have secondary effects. The results of using the optigenetic set up along with live cell imaging are that cells become more motile and disrupt normal epithelial cell-cell adhesions. This behavior is believed to be due to increased cell contractility downstream of calcium signaling, and is dependent on Ca2+/calmodulin-dependent protein kinase II (CaMKII). When cells are pre-treated with CaMKII inhibitor before HGF addition, they undergo the spreading step of EMT without subsequent cellular contraction and rupture of cell-cell junctions. CaMKII is a protein kinase that is activated by binding Ca2+/calmodulin, and is a known downstream component of calcium signaling. CaMKII is known to affect the actin cytoskeleton by both physically bundling actin filaments to increase their rigidity, and through signaling by activation of myosin light chain kinase (MLCK), which has a role in stress fiber formation. Immunofluorescence did not show colocalization of CaMKII with actin, ruling out regulation through actin bundling. However, CaMKII does appear to have a role in stress fiber formation. EMT induced with HGF treatment results in increased numbers of stress fibers as well as trans-cellular actin network formation, both actin structures decorated with non-muscle myosin II (NMII). CaMKII inhibition not only blocks these actin formations, but it also decreases stress fiber levels below basal unstimulated levels in cells that have not been treated with HGF. This suggests that CaMKII has a role in regulating contractility through cellular actin networks, indicating a mechanism for calcium's role in cellular contractility in EMT.

APA, Harvard, Vancouver, ISO, and other styles

42

Nguyen, Emily Kim. "Mitochondrial Ca2+/Calmodulin-dependent kinase ii (CaMKII) regulates smooth muscle cell migration and neointimal formation via mitochondrial Ca2+ uptake and mobility." Diss., University of Iowa, 2019. https://ir.uiowa.edu/etd/6819.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Patton, Bruce L. Mary B. Kennedy Mary B. Kennedy. "Autophosphorylation sites on the type II CA2+/calmodulin-dependent protein kinase : identification, regulation of kinase activity, and site-specific antibodies /." Diss., Pasadena, Calif. : California Institute of Technology, 1991. http://resolver.caltech.edu/CaltechETD:etd-07232007-144526.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Tong, Michael. "Evaluation of protein kinases for solution NMR spectroscopy and the structural mechanism of inhibition and activation of an oncogenic calcium calmodulin dependent protein kinase." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3877/.

Full text

Abstract:

Protein kinases are important mediators of cell signalling that are often implicated in disease when deregulation occurs. The catalytic kinase domain is highly conserved with 518 identified members in the super family. Kinase structural studies are mainly based on relatively static crystal structures. However protein kinases are inherently dynamic entities in solution. Several Ser/Thr protein kinases were evaluated by NMR in order to obtain an amenable target for solution structure and functional characterisation. Subsequently a calcium calmodulin dependent protein kinase dubbed CaMK1D was identified as the optimal system. CaMK1D normally mediates intracellular signalling downstream of chemokines. It is amplified in breast cancer, and induces cell proliferation, migration and invasion. Here we report the backbone resonance assignments for the 38 kDa human autoinhibited CaMK1D in its free state, encompassing a canonical bi-lobed kinase fold and autoinhibitory and calmodulin binding domains. These assignments allowed us to probe the binding mode of CaMK1D with small molecule ligands and refine the crystal structure via dihedral angle restraints for a more complete structure. Furthermore we investigated the solution structure of the CaMK1D∙Ca\(^{2+}\)/CaM complex and propose a model of the activation mechanism and establish a key residue implicated in complex formation.

APA, Harvard, Vancouver, ISO, and other styles

45

Dong, Yu. "Ca²⁺/calmodulin dependent protein kinase II subcellular re-distribution and activation of protein phosphatase after a brief pentylenetetrazol seizure potential role in kindling /." Connect to full-text via OhioLink ETD Center, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=mco1082463968.

Full text

Abstract:

Thesis (Ph. D.)--Medical College of Ohio, 2003.
"In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Medical Sciences." Major advisor: Howard Rosenberg. Document formatted into pages: iv, 144 p. Title from title page of PDF document. Includes bibliographical references (p. 104-132).

APA, Harvard, Vancouver, ISO, and other styles

46

Dong, Yu. "Ca2+/Calmodulin Dependent Protein Kinase II Subcellular Re-distribution and Activation of Protein Phosphatase After a Brief Pentylenetertrazol Seizure: Potential Role in Kindling." University of Toledo Health Science Campus / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=mco1082463968.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Mukwevho, Emmanuel. "Regulation of Glut-4 Expression in Skeletal Muscle cells: The Roles of Nuclear Respiratory Factor-1 and calcium/calmodulin dependent protein Kinase." Doctoral thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/3272.

Full text

Abstract:

GLUT4 protein is the major glucose transporter in skeletal muscle and is vital in the maintenance of euglycemia (17; 108). Underexpression of GLUT4 or impairement of its translocation from intracellular compartments to the cell surface, are linked to diminished glucose transport, hyperglycemia and type II diabetes (59; 61; 153). Type II diabetes can be alleviated by increasing GLUT4 expression (223). Previous reports have shown that overexpression of NRF-1 and activation of CaMKII increases GLUT4 expression but the mechanisms involved have not be characterized (10; 173). Therefore, the objective of this thesis was to investigate the molecular mechanisms by which NRF-1 and CaMK II regulate GLUT4 expression in C2C12 myocytes. We engineered C2C12 cells that overexpressed NRF-1 in response to doxycycline (Dox) using a Tet-On gene expression system and assessed the effects of NRF-1 overexpression on: a) MEF2A, GLUT4 and Î´ALAS proteins by western blot, and b) the binding of NRF-1 to mef2a and Î´alas genes and MEF2A to the glut4 gene, by chromatin immunoprecipitation assay (ChIP). The importance of MEF2A in NRF-1-induced increase in GLUT4 expression was investigated by silencing MEF2A expression using small interference RNA (siRNA). CaMK II was activated in wild-type C2C12 myocytes using 10 mM caffeine and was inhibited by 25 Î¼ M KN93. Acetylation of histones in the vicinity of NRF-1 and MEF2A binding sites on the mef2a and glut4 genes, respectively, were assessed by ChIP assay. HDAC5 nuclear export was assessed by immunocytochemistry and mRNA levels by qRT-PCR. Overexpression of NRF-1 resulted in ~3-fold increases in mef2a-bound NRF-1 and glut4 -bound MEF2A at 6 h and 8 h post Dox treatment, respectively. MEF2A and GLUT4 proteins were both increased ~1.6-fold at 6 h and 18 h post Dox treatment. Silencing of MEF2A caused a marked downregulation of GLUT4 expression in NRF-1-overexpressing cells.

APA, Harvard, Vancouver, ISO, and other styles

48

Shen, Guofu. "Bidirectional Regulation of AMPA and NMDA Receptors during Benzodiazepine Withdrawal." University of Toledo Health Science Campus / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=mco1242680312.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Blair, Robert Eagan. "Changes in GABAA̳ Receptor Expression and Alterations in Ca⁺⁺/Calmodulin-Dependent Protein Kinase II Activity in a Hippocampal Neuronal Culture Model of Epilepsy." VCU Scholars Compass, 1998. http://scholarscompass.vcu.edu/etd/4358.

Full text

Abstract:

Expression levels of GABAA receptor subunits and activity of the Ca++ /calmodulin-dependent protein kinase II (CaM kinase II) enzyme system were evaluated in an in vitro hippocampal neuronal culture model of epilepsy. Treatment of hippocampal neuronal cultures with Mg++-free media for 3 hours results in the induction of an enduring "epileptic" state as evidenced by the expression of spontaneous recurrent seizure (SRS) discharge. The induction of the SRS activity was shown to be a N-methyl-D-aspartate (NMDA) receptor, Ca++-dependent mechanism (Sombati and DeLorenzo, J Neurophys., 73 (4), 1995). Significant and long-lasting decreases in mRNA expression for the GABAA α2 and α5 receptor subunits were observed in association with the induction of SRSs in this model, while levels for α1, β2 and γ2 subunits showed no significant change. Irreversible [3H]-flunitrazepam saturation binding analysis in membrane preparations demonstrated a significant decrease in specific binding in association with the SRS activity observed in this model. No changes in GABAA P subunit immunoreactivity were detected. Selective suppression of the GABAA α2 subunit protein levels in hippocampal neuronal cultures using antisense oligonucleotide technology caused a significant decrease in the amplitude of spontaneous inhibitory postsynaptic currents (sIPSC). CaM kinase II is highly enriched in the brain and mediates many processes essential to neuronal function and viability. Induction of SRSs in hippocampal cultures were associated with a long-lasting and significant decrease in activity of CaM kinase II. Addition of 2-amino-5-phosphovaleric acid to the low Mg++ treatment solution prevented the decrease in CaM kinase II activity. Suppression of CaM kinase II activity in hippocampal cultures by treatment with either an antisense oligonucleotide specific for a CaM kinase II or KN93 (selective CaM kinase II inhibitor) resulted in significant reductions in IPSC amplitude. This data suggests that CaM kinase II can act to regulate GABAergic inhibitory function in hippocampal cultures. The findings of this study demonstrate long-lasting decreases in GABAA receptor expression and activity of CaM kinase II, which may contribute to the induction of the "epileptic" state of this model.

APA, Harvard, Vancouver, ISO, and other styles

50

Anil, Veena S. "Study of Ca2+-Mediated Signal Transduction During Embryogenesis In Sandalwood (Santalurm Album L.) And Characterization Of An Early Development-Specific CDPK." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/179.

Full text

Abstract:

Calcium ion plays a pivotal role as second messenger during signal/response coupling in plant cells (Trewavas, 1999). Elevations of cytosolic Ca2+ occur in plants as a consequence of abiotic and biotic stresses, environmental and hormonal stimuli. However, the molecular mechanism by which changes in cytosolic calcium are sensed and transduced in the plant cell has not been completely elucidated. The detection of Ca2+-binding proteins, especially Ca2+-dependent protein kinases (CDPKs) in plants led to drawing analogy with animal systems wherein the Ca2+-message is perceived and transduced by proteins that bind Ca2+. CDPKs are stimulated by the direct binding of Ca2+ to their endogenous calmodulin (CaM) -like domain (Harper et al, 1991). CDPKs exist as multiple isoforms in a single species, and show tissue-specific and developmentally regulated expression. Furthermore, the diversity among different CDPK isoforms with respect to Ca2+-binding properties, activation, substrate specificity, regulatory mechanisms and other kinetic properties suggest their specialization in the regulation of distinct signaling pathways. These observations therefore have led to the speculation that most of the Ca2+-mediated signal transduction in plants occurs via the mediation of CDPKs (Harmon et al, 2000). Over the last 15 years there has been a dramatic unfolding of information on Ca2+-mediated signaling in plants. Nevertheless, little is known about the environmental/hormonal signals and the signaling events that regulate early plant developmental processes such as embryogenesis, seed development and germination. The present investigation was initiated with the objectives 1) to determine the role of Ca2+ during embryogenesis, 2) to examine the involvement of a CDPK during early developmental processes in sandalwood plant (Santalum album L.) and 3) to purify and biochemically characterize this CDPK. The study initially investigated the possible involvement of calcium-mediated signaling in the induction/regulation of somatic embryogenesis from proembryogenic cells of sandalwood. 45 Ca + uptake studies and fura-2 fluorescence ratio photometry were used to measure changes in [Ca2+]cyt of proembryogenic cells in response to culture conditions conducive for embryo development. Sandalwood proembryogenic cell masses (PEMs) were obtained in the callus proliferation medium that contains the auxin 2,4-D. Subculture of PEMs into the embryo differentiation medium which lacks 2,4-D and has higher osmoticum resulted in a 4-fold higher 45Ca2+ incorporation into the symplast. Fura-2 based ratiometric analysis also showed a 10-16- fold increase in the [Ca2+]cyt of PEMs under identical culture conditions, increasing from a resting concentration of 30-50 nM to 650-800 nM. Chelation of exogenous Ca2+ with EGTA arrested such an elevation in [Ca2+]cyt. Exogenous Ca2+ when chelated or deprived also arrested embryo development and inhibited the accumulation of a Ca2+-dependent protein kinase (swCDPK) in embryogenic cultures. However, such culture conditions did not cause cell death as the PEMs continued to proliferate to form larger cell clumps. Culture treatment with W7 reduced embryogenic frequency by 85%, indicating that blockage of Ca2+-mediated signaling pathway(s) involving swCDPK and/or CaM caused inhibition of embryogenesis. These observations suggest a second messenger role for exogenous Ca2+ and the existence of Ca2+-mediated signaling pathway(s) during sandalwood somatic embryogenesis. The detection of a 55 kD protein showing cross reactivity with polyclonal antisoybean CDPK and the detection of Ca2+-dependent protein kinase activity in protein extracts from somatic embryos, prompted investigation on the spatio-temporal accumulation and activity of a CDPK in different developmental stages of sandalwood. Western blot analysis and protein kinase assays identified a Ca2+-dependent protein kinase (swCDPK) of 55 kD in soluble protein extracts of different developmental stages of sandalwood somatic embryos. However, swCDPK was not detected in plantlets regenerated from somatic embryos. swCDPK exhibited differential expression and activity in the developmental stages of sandalwood. Zygotic embryos, endosperm and seedlings showed high accumulation of swCDPK. However, the enzyme was not detected in the soluble proteins of shoots and flowers of sandalwood tree. swCDPK exhibited a temporal pattern of expression in endosperm, showing high accumulation and activity in mature fruit and germinating stages, the enzyme being localized strongly in the storage bodies of the endosperm cells. Interestingly, these storage bodies were thereafter identified as oil bodies, suggesting that a Ca2+-mediated regulation of oil hydrolysis and/or mobilization might be operative during seed germination. swCDPK in the zygotic embryo was found to be inactive during seed dormancy and early stages of germination, indicating a possible post-translational hibition/inactivation of the enzyme during these stages. The temporal expression of swCDPK during somatic/zygotic embryogenesis, seed maturation and germination thus suggests involvement of the enzyme in these early developmental processes. In view of the diversity exhibited by members of the CDPK family, characterization of swCDPK, the early development specific CDPK from sandalwood was undertaken. Purification of swCDPK was achieved by chromatography on DEAE-cellulose, hydroxyapatite and Blue-Sepharose. The purified enzyme resolved into a single band on 10 % polyacrylamide gels, both under denaturing and non-denaturing conditions. swCDPK was strictly dependent on Ca2+, K0.5 (apparent binding constant) for Ca2+-activation of substrate phosphorylation activity being 0.7 μM and for autophosphorylation activity —50 nM. Ca2+-dependence for activation, CaM-independence, inhibition by CaM-antagonist (IC50 for W7 = 6 μM, for W5 = 46 μM) and cross-reaction with polyclonal antibodies directed against the CaM-like domain of soybean CDPK, confirmed the presence of an endogenous CaM-like domain in the purified enzyme. Kinetic studies revealed a Km value of 13 mg/mL for histone III-S and a Vmax of 0.1 nmolmin-1rng-1. The enzyme exhibited high specificity for ATP with a Km value of 10 nM. Titration with Ca2+ resulted in enhancement of the intrinsic emission fluorescence of swCDPK and a shift in the λmax emission from tryptophan residues. A reduction in the efficiency of non-radiative energy transfer from tyrosine to tryptophan residues was also observed. These are taken as evidence for the occurrence of Ca2+-induced conformational change in swCDPK. The emission spectral properties of swCDPK in conjunction with Ca2+ levels required for autophosphorylation and substrate phosphorylation help elucidate the possible mode of Ca2+ activation of this enzyme.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!