RGD Reference Report - Cholecystokinin-stimulated tyrosine phosphorylation of PKC-delta in pancreatic acinar cells is regulated bidirectionally by PKC activation. - Rat Genome Database

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Cholecystokinin-stimulated tyrosine phosphorylation of PKC-delta in pancreatic acinar cells is regulated bidirectionally by PKC activation.

Authors: Tapia, JA  Bragado, MJ  Garcia-Marin, LJ  Jensen, RT 
Citation: Tapia JA, etal., Biochim Biophys Acta 2002 Dec 16;1593(1):99-113.
RGD ID: 631304
Pubmed: PMID:12431789   (View Abstract at PubMed)

PKC-delta is important in cell growth, apoptosis, and secretion. Recent studies show its stability is regulated by tyrosine phosphorylation (TYR-P), which can be stimulated by a number of agents. Many of these stimuli also activate phospholipase C (PLC) cascades and little is known about the relationship between these cascades and PKC-delta TYR-P. Cholecystokinin (CCK) stimulates PKCs but it is unknown if it causes PKC-delta TYR-P and if so, the relationship between these cascades is unknown. In rat pancreatic acini, CCK-8 stimulated rapid PKC-delta TYR-P by activation of the low affinity CCK(A) receptor state. TPA had a similar effect. BAPTA did not decrease CCK-stimulated PKC-delta TYR-P but instead, increased it. A23187 did not stimulate PKC-delta TYR-P. Wortmannin and LY 294002 did not alter CCK-stimulated PKC-delta TYR-P. GF 109203X, at low concentrations, increased PKC-delta TYR-P stimulated by CCK or TPA and at higher concentrations, inhibited it. The cPKC inhibitors, Go 6976 and safingol, caused a similar increase in TPA- and CCK-stimulated PKC-delta TYR-P. These results demonstrate that CCK(A) receptor activation causes PKC-delta TYR-P through activation of only one of its two receptor affinity states. This PKC-delta TYR-P is not directly influenced by changes in [Ca(2+)](i); however, the resultant activation of PKC-alpha has an inhibitory effect. Therefore, CCK activates both stimulatory and inhibitory PKC cascades regulating PKC-delta TYR-P and, hence, likely plays an important role in regulating PKC-delta degradation and cellular abundance.

Objects referenced in this article
Gene Cckar cholecystokinin A receptor Rattus norvegicus
Gene Prkcd protein kinase C, delta Rattus norvegicus

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