Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We performed a nonradioactive in situ hybridization histochemistry (ISH) study of the lateral geniculate nucleus (LGN) and the primary visual area (area 17) of the macaque monkey to investigate mRNA expression of the myristoylated alanine-rich C-kinase substrate (MARCKS), a major protein kinase C (PKC) substrate. In the LGN, intense hybridization signals were observed in both magnocellular neurons (layers 1 and 2) and parvocellular neurons (layers 3 to 6). Double labeling using ISH and immunofluorescence revealed that MARCKS mRNA was coexpressed with the alpha-subunit of type II calcium/calmodulin-dependent protein kinase, indicating that MARCKS mRNA is also expressed in koniocellular neurons in the LGN. GABA-immunoreactive neurons in the LGN did not contain MARCKS mRNA, indicating that MARCKS mRNA is not expressed in inhibitory interneurons. The signals were generally weak in area 17, and intense signals were restricted to large neurons in layers IVB, V, and VI. GABA-immunoreactive neurons in layers II-VI of area 17 did not contain MARCKS mRNA. Double-label ISH revealed that MARCKS mRNA was coexpressed with mRNA of GAP-43, another PKC substrate, in neurons of both the LGN and area 17. To determine whether the expression of MARCKS mRNA is regulated by retinal activity, we performed ISH in the LGN and area 17 of monkeys deprived of monocular visual input by tetrodotoxin. After monocular deprivation for 5 to 30 days, MARCKS mRNA was down-regulated in the LGN, but not in area 17. These results suggest that MARCKS mediates the activity-dependent changes in the excitatory relay neurons in the LGN.
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PMID:Expression of MARCKS mRNA in lateral geniculate nucleus and visual cortex of normal and monocularly deprived macaque monkeys. 1250 29

Activation of PKC depends on the availability of DAG, a signaling lipid that is tightly and dynamically regulated. DAG kinase (DGK) terminates DAG signaling by converting it to phosphatidic acid. Here, we demonstrate that DGKzeta inhibits PKCalpha activity and that DGK activity is required for this inhibition. We also show that DGKzeta directly interacts with PKCalpha in a signaling complex and that the binding site in DGKzeta is located within the catalytic domain. Because PKCalpha can phosphorylate the myristoylated alanine-rich C-kinase substrate (MARCKS) motif of DGKzeta, we tested whether this modification could affect their interaction. Phosphorylation of this motif significantly attenuated coimmunoprecipitation of DGKzeta and PKCalpha and abolished their colocalization in cells, indicating that it negatively regulates binding. Expression of a phosphorylation-mimicking DGKzeta mutant that was unable to bind PKCalpha did not inhibit PKCalpha activity. Together, our results suggest that DGKzeta spatially regulates PKCalpha activity by attenuating local accumulation of signaling DAG. This regulation is impaired by PKCalpha-mediated DGKzeta phosphorylation.
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PMID:Association of diacylglycerol kinase zeta with protein kinase C alpha: spatial regulation of diacylglycerol signaling. 1262 49

The myristoylated alanine-rich C-kinase substrate protein (MARCKS) is a widely expressed target of protein kinase C (PKC) phosphorylation. Disruption of Marcks in mice leads to a number of developmental defects within the central nervous system that are completely prevented by expression of an epitope-tagged wild-type human MARCKS transgene. In the present study, we investigated whether PKC phosphorylation of MARCKS is necessary for normal central nervous system development and postnatal survival. Expression at approximately twice normal levels of a mutant MARCKS protein in which the four PKC phosphorylatable serines were replaced by asparagines did not allow postnatal survival of Marcks(-/-) pups. Nonetheless, the rescued animals exhibited none of the characteristic anatomical defects seen in the brains and retinas of knockout mice, suggesting that PKC phosphorylation of MARCKS is not required for normal central nervous system development. Expression studies showed that transgene expression was limited to the central nervous system, which has implications for the lack of postnatal survival as well as for the pathogenesis of the neuronal ectopia characteristic of MARCKS deficiency. A novel aspect of the MARCKS-deficient phenotype was also noted, absence of the pontine nuclei; this was also largely reversed in Marcks(-/-) animals expressing the mutant transgene. These data raise the possibility of a role for MARCKS in the netrin-regulated process of pontine nuclei formation.
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PMID:Neuroanatomical development in the absence of PKC phosphorylation of the myristoylated alanine-rich C-kinase substrate (MARCKS) protein. 1288 15

Myristoylated alanine-rich C-kinase substrate (MARCKS) is an actin-binding protein whose function may be regulated by the phosphorylation of multiple sites, in which the phosphorylation site domain (PSD) is recognized to have three or four PKC-dependent sites. Recently, it is considered that MARCKS is implicated in some neuronal functions, such as synaptic vesicle trafficking and neurotransmitter release, through regulation of the actin-containing cytoskeletal structure; this is based on the experimental results with short-term or prolonged pretreatment with phorbol esters and treatment by protein kinase C (PKC) inhibitor. However, the precise molecular mechanism is yet obscure. Recently, we have demonstrated that MARCKS is phosphorylated at Ser159 in PSD by Rho-kinase in vitro and that the phosphorylation occurred in neuronal cells upon stimulation with lysophosphatidic acid (LPA), and its phosphorylation was inhibited by a novel and specific Rho-kinase inhibitor, H-1152. Our results allow us to speculate that a preinflammatory substance, such as LPA, interleukin 1-beta, and bradykinin, augments MARCKS phosphorylation in a novel signal transduction pathway besides the PKC-involved one, and thereby induces the release of a neurotransmitter through a reorganization of actin-containing microfilaments at the cell periphery, the so-called "active zone". In this section, I address a novel mechanism for MARCKS phosphorylation and its related cellular function.
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PMID:New aspects of neurotransmitter release and exocytosis: Rho-kinase-dependent myristoylated alanine-rich C-kinase substrate phosphorylation and regulation of neurofilament structure in neuronal cells. 1450 Nov 49

Protein phosphorylation in neutrophils was monitored with two phosphospecific antibodies (pAbs) [termed pPKC(S1) Ab and pPKC(S2) Ab] that recognize products of protein kinase C (PKC) and other Arg/Lys-directed Ser/Thr protein kinases. The pPKC(S1) Ab bound preferentially to p-Ser/p-Thr residues with Arg or Lys in the -3 and -5 positions or the -2 and -3 positions, whereas the pPKC(S2) Ab bound preferentially to p-Ser with Arg or Lys in the -2 and +2 positions and with a hydrophobic residue at the +1 position. Phosphorylated pleckstrin, myristoylated alanine-rich C-kinase substrate (MARCKS), the 47-kDa subunit of the phagocyte oxidase (p47-phox) and numerous unidentified proteins that underwent phosphorylation during neutrophil stimulation were readily detected with these pAbs. Priming effects of tumor necrosis factor alpha (TNF-alpha) and the susceptibility of certain reactions in neutrophils to inhibitors of protein kinases could also be easily investigated with these reagents. Compared to the commonly used 32P-labeling/autoradiographic method, Western blotting with pAbs was found to be a faster, safer, more specific and in many cases more sensitive approach for monitoring protein phosphorylation events in neutrophils. These pAbs may facilitate the identification of several new phosphorylation reactions involved in neutrophil stimulation.
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PMID:Protein phosphorylation in neutrophils monitored with phosphospecific antibodies. 1458 Aug 83

We performed nonradioactive in situ hybridization histochemistry in the monkey cerebellum to investigate the localization of protein kinase C-substrate (growth-associated protein-43 [GAP-43], myristoylated alanine-rich C-kinase substrate [MARCKS], and neurogranin) mRNAs. Hybridization signals for GAP-43 mRNA were observed in the molecular and granule cell layers of both infant and adult cerebellar cortices. Signals for MARCKS mRNA were observed in the molecular, Purkinje cell, and granule cell layers of both infant and adult cortices. Moreover, both GAP-43 and MARCKS mRNAs were expressed in the external granule cell layer of the infant cortex. In the adult cerebellar vermis, signals for both GAP-43 and MARCKS mRNAs were more intense in lobules I, IX, and X than in the remaining lobules. In the adult hemisphere, both mRNAs were more intense in the flocculus and the dorsal paraflocculus than in other lobules. Such lobule-specific expressions were not prominent in the infant cerebellar cortex. Signals for neurogranin, a postsynaptic substrate for protein kinase C, were weak or not detectable in any regions of either the infant or adult cerebellar cortex. The prominent signals for MARCKS mRNA were observed in the deep cerebellar nuclei, but signals for both GAP-43 and neurogranin mRNAs were weak or not detectable. The prominent signals for both GAP-43 and MARCKS mRNAs were observed in the inferior olive, but signals for neurogranin were weak or not detectable. The cell type- and region-specific expression of GAP-43 and MARCKS mRNAs in the cerebellum may be related to functional specialization regarding plasticity in each type of cell and each region of the cerebellum.
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PMID:Cell type- and region-specific expression of protein kinase C-substrate mRNAs in the cerebellum of the macaque monkey. 1459 65

The regulation of the cytoskeleton is critical to normal cell function during tissue morphogenesis. Cell-matrix interactions mediated by integrins regulate cytoskeletal dynamics, but the signaling cascades that control these processes remain largely unknown. Here we show that myristoylated alanine-rich C-kinase substrate (MARCKS) a specific substrate of protein kinase C (PKC), is regulated by alpha5beta1 integrin-mediated activation of PKC and is critical to the regulation of actin stress fiber formation during muscle cell spreading. Using MARCKS mutants that are defective in membrane association or responsiveness to PKC-dependent phosphorylation, we demonstrate that the translocation of MARCKS from the membrane to the cytosol in a PKC-dependent manner permits the initial phases of cell adhesion. The dephosphorylation of MARCKS and its translocation back to the membrane permits the later stages of cell spreading during the polymerization and cross-linking of actin and the maturation of the cytoskeleton. All of these processes are directly dependent on the binding of alpha5beta1 integrin to its extracellular matrix receptor, fibronectin. These results demonstrate a direct biochemical pathway linking alpha5beta1 integrin signaling to cytoskeletal dynamics and involving bi-directional translocation of MARCKS during the dramatic changes in cellular morphology that occur during cell migration and tissue morphogenesis.
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PMID:The bi-directional translocation of MARCKS between membrane and cytosol regulates integrin-mediated muscle cell spreading. 1531 66

Myristoylated alanine-rich C-kinase substrate (MARCKS) is a major neuron-specific substrate for protein kinase C, and is involved in both neurite outgrowth and synaptic plasticity. Using both Northern blot and in situ hybridization techniques, we investigated whether the expression of MARCKS mRNA in the monkey cerebral neocortex and hippocampus changed during the developmental period. In each of four neocortical areas examined, i.e. the prefrontal area (area FD of [Illinois Monographs in the Medical Sciences (1947) 1]), the temporal association area (TE), the primary somatosensory area (PB), and the primary visual area (OC), the Northern blot analysis showed that the amount of MARCKS mRNA was high during the fetal and early postnatal periods, and decreased sharply between postnatal day 70 and postnatal month 6. The in situ hybridization experiments showed that the expression of MARCKS mRNA was decreased in every layer of neocortical areas at postnatal month 6 or later. In the primary sensory areas (areas PB and OC), the degree of decrease was higher in the supragranular layers (layers II and III) than in the infragranular layers (layers V and VI). In the hippocampus, the developmental change in the amount of MARCKS mRNA was small, but the in situ hybridization revealed a prominent decrease in Ammon's horn in monkeys on postnatal month 8 and later. These findings indicate that region-specific expression of MARCKS mRNA is established around postnatal month 6. We suggest that the extensive expression of MARCKS mRNA is one of the molecular bases of high plasticity in the infant cerebral cortex.
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PMID:Northern blot and in situ hybridization analyses for the development of myristoylated alanine-rich c-kinase substrate mRNA in the monkey cerebral cortex. 1548 39

VEGF-KDR/Flk-1 signal utilizes the phospholipase C-gamma-protein kinase C (PKC)-Raf-MEK-ERK pathway as the major signaling pathway to induce gene expression and cPLA2 phosphorylation. However, the spatio-temporal activation of a specific PKC isoform induced by VEGF-KDR signal has not been clarified. We used HEK293T (human embryonic kidney) cells expressing transiently KDR to examine the activation mechanism of PKC. PKC specific inhibitors and human PKCdelta knock-down using siRNA method showed that PKCdelta played an important role in VEGF-KDR-induced ERK activation. Myristoylated alanine-rich C-kinase substrate (MARCKS) translocates from the plasma membrane to the cytoplasm depending upon phosphorylation by PKC. Translocation of MARCKS-GFP induced by VEGF-KDR stimulus was blocked by rottlerin, a PKCdelta specific inhibitor, or human PKCdelta siRNA. VEGF-KDR stimulation did not induce ERK phosphorylation in human PKCdelta-knockdown HEK293T cells, but co-expression of rat PKCdelta-GFP recovered the ERK phosphorylation. Y311/332F mutant of rat PKCdelta-GFP which cannot be activated by tyrosine-phosphorylation but activated by DAG recovered the ERK phosphorylation, while C1B-deletion mutant of rat PKCdelta-GFP, which can be activated by tyrosine-phosphorylation but not by DAG, failed to recover the ERK phosphorylation in human PKCdelta-knockdown HEK293T cell. These results indicate that PKCdelta is involved in VEGF-KDR-induced ERK activation via C1B domain.
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PMID:Activation and translocation of PKCdelta is necessary for VEGF-induced ERK activation through KDR in HEK293T cells. 1554 67

We performed experiments in spinal cords isolated from neonatal rats to probe the mechanisms responsible for hyperresponsiveness of the population excitatory evoked potential (pEPSP) observed on washout of the volatile anesthetics halothane and isoflurane (1 minimal alveolar anesthetic concentration equivalent, MAC) compared with that observed after an anesthetic concentration of ethanol. After 30 min exposure to each anesthetic and washout, pEPSP area increased to levels significantly more than control (P < 0.01-0.001). Exposure to a very small (0.025 MAC) concentration of isoflurane over the same period itself produced a similarly exaggerated pEPSP (P < 0.05) in the continued presence of the drug, suggesting that the phenomenon is a direct excitatory effect of the small concentrations of anesthetic on washout, unlike the true withdrawal observed with ethanol. Isoflurane, but not halothane, significantly increased the amount of potassium-stimulated release of the excitatory neurotransmitters glutamate, aspartate, and substance P, suggesting the hyperresponsiveness for that drug is the result of a presynaptically mediated increase in transmitter release. A broad spectrum specific protein kinase C inhibitor, GF109203X, blocked ethanol withdrawal hyperresponsiveness but not hyperresponsiveness after halothane. If the behavioral symptoms of emergence from anesthesia are based on excitatory actions similar to those observed in the spinal cord, the results show that they represent direct excitatory actions rather than withdrawal and are attributable to direct actions on ion channels or receptors, rather than indirect effects mediated by protein kinase C.
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PMID:Hyperresponsiveness on washout of volatile anesthetics from isolated spinal cord compared to withdrawal from ethanol. 1567 68


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