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Ca2+-Dependent protein kinase

Protein kinase C (PKC) comprises the other major class of Ca2+-dependent protein kinases and is activated by Ca2+ in conjunction with DAG and phosphatidylserine (discussed in Ch. 20). Multiple forms of PKC have been cloned, and the brain is known to contain at least seven species of the enzyme. The variant forms of PKC exhibit different cellular distributions in the brain and different regulatory properties. For example, they differ in the relative ability of Ca2+ and DAG to activate them some require both Ca2+ and DAG, whereas others can be activated by DAG alone, apparently without an increase in cellular Ca2+ concentrations. However, these enzymes show similar substrate specificities and, as a result, are often considered isoforms. [Pg.396]

Several key questions remain with regard to the regulation of tyrosine hydroxylase by phosphorylation. What is the precise effect of the phosphorylation of each of these serine residues on the catalytic activity of the enzyme How does the phosphorylation of multiple residues affect enzyme activity Does the phosphorylation of one residue affect the ability of the others to be phosphorylated Tyrosine hydroxylase provides a striking example as to how multiple intracellular messengers and protein kinases converge functionally through the phosphorylation of a single substrate protein. Phosphorylation of tyrosine hydroxylase by cAMP-dependent and Ca2+-dependent protein kinases and by MAPK cascades... [Pg.404]

The cAMP and Ca2+ pathways also interact at the level of protein kinases and protein phosphatases. This is illustrated by inhibitor-1 and DARPP-32, which are phosphorylated and activated by PKA and then inhibit PP1, which can dephosphorylate numerous substrates for Ca2+-dependent protein kinases. Another example is the physical association between PKA and PP2B (a Ca2+/ calmodulin-activated enzyme) via the AKAP-anchoring proteins. [Pg.410]

Ca2+-CaM-dependent Protein Kinase Ca2+-dependent Protein Kinase Central Nervous System... [Pg.547]

Regulation of acetyl-CoA carboxylase by phosphorylation and dephosphorylation. Glucagon is known to activate cAMP-dependent protein kinase this kinase phosphorylates both serine 77 and serine 1200 of rat acetyl-CoA carboxylase, which inactivates the enzyme. However, there is also an AMP-dependent kinase that phosphorylates serine 79 and serine 1200 and inactivates the rat acetyl-CoA carboxylase. The relative importance of these two kinases in regulating the carboxylase in vivo is still unclear. Likewise, the phosphorylated enzyme is a substrate for several different protein phosphate phosphatases, and the physiologically relevant phosphatases are not known. Epinephrine may inhibit the carboxylase via a Ca2+-dependent protein kinase. [Pg.432]

The release of Ca2+ in response to such second messengers is known to activate the phosphorylation of a range of cytosolic proteins by Ca2+-dependent protein kinases, for example in hepatocytes,417 adrenal cortex418 and other cells.419 Ca2+ inhibits cAMP-activated protein kinase in parathyroid glands.420 Phosphorylation of proteins produced in the pancreatic /8-cell in response to enhanced [Ca2+] may involve calmodulin, while the stimulus produced by glucose is potentiated by cAMP 421 A calmodulin-activated NAD kinase is present in the outer mitochondrial membrane of com.422... [Pg.595]

Activation of m responses. Stimulation of 1 receptors by catecholamines leads to the activation of a Gq coupling protein. The o-subunit of this G protein activates the effector, phospholipase C, which leads to the release of IP3 (inositol 1,4,5-trisphosphate) and DAG (diacylglycerol) from phosphatidylinositol 4,5-bisphosphate (Ptdlns 4,5-Pq). IP3 stimulates the release of sequestered stores of calcium, leading to an increased concentration of cytoplasmic Ca2+. Ca2+ may then activate Ca2+-dependent protein kinases, which in turn phosphorylate their substrates. DAG activates protein kinase C. See text for additional effects of 1 receptor activation. [Pg.175]

Gotow T, Miyaguchi K, Hashimoto PH (1991) Cytoplasmic architecture of the axon terminal filamentous strands specifically associated with synaptic vesicles. Neuroscience 40 587-98 Gower H, Rodnight R, Brammer MJ (1986) Ca2+ sensitivity of Ca2+-dependent protein kinase activities toward intrinsic proteins in synaptosomal membrane fragments from rat cerebral tissue. J Neurochem 46 440-7... [Pg.249]

As illustrated in Table I, many hormones act by stimulating membrane-bound phospholipases. The most commonly affected enzyme is a phospholipase C with specificity for phosphoinositides, i.e., a phosphoinositidase C (PIC) and, among these, the most relevant has specificity for phosphatidylinositol bisphosphate yielding inositol trisphosphate (IP3) and diacylglycerol (DAG). IP3 and DAG act as second messengers to mobilize Ca2+ from intracellular stores and activate the phospholipid- and Ca2+-dependent protein kinase, respectively (protein kinase C) (for reviews see Refs. 87-90). A typical Gp-mediated response of this type occurs in neutrophils exposed to the chemoattractant peptide fMLP [91]. fMLP binds to specific membrane receptors which recognize proteolyzed fragments of bacterial pro-... [Pg.11]

DAGs have been shown to stimulate a Ca2+-dependent protein kinase (PKC) by increasing the affinity of this enzyme for phospholipids and Ca2+ [95,96]. Initial evidence for a similar mechanism in the GnRH stimulus transmission was obtained from experiments in which phorbol dibutyrate and phorbol 12-myristate 13-acetate were able to stimulate LH release [53,97,98]. This stimulatory effect of phorbol esters is probably caused by binding and activation of PKC, thereby mimicking endogenous DAGs [99]. [Pg.147]

CDK2, cell division kinase 2 cDNA, complementary DNA CDP, cytidine 5 -diphosphate CDPK, Ca2+-dependent protein kinase, calmodulin domain protein kinase CFTR, cystic fibrosis transmembrane conductance regulator cGMP, 3, 5 -c.yclic guanosine monophosphate cGMP PDE, cyclic GMP phosphodiesterase... [Pg.840]

McPhail LC, Clayton CC, Snyderman R. A Potential 2nd messenger role for unsaturated fatty-acids—activation of Ca2+-dependent protein-kinase. Science 1984 224 622-625. [Pg.79]

Diacylglycerol is another product of the phosphodiesteratic cleavage of the Inosltides that has recently acquired enhanced importance. 1,2-Diacylglycerol activates a phospholipid- and Ca2+-dependent protein kinase C which is implicated in transmembrane signalling, tumor promotion and cellular differentiation.95,96 1,2-Diacyl-... [Pg.218]


See other pages where Ca2+-Dependent protein kinase is mentioned: [Pg.568]    [Pg.340]    [Pg.394]    [Pg.172]    [Pg.544]    [Pg.61]    [Pg.523]    [Pg.528]    [Pg.544]    [Pg.275]    [Pg.182]    [Pg.597]    [Pg.491]    [Pg.255]    [Pg.845]    [Pg.568]    [Pg.460]    [Pg.828]    [Pg.858]    [Pg.883]   
See also in sourсe #XX -- [ Pg.547 ]




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