Different translocation and calcium dependence of protein kinase C isoforms induced by phorbol ester in human platelets

Conference · Mon Mar 11 04:00:00 EST 1991 · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)

OSTI ID:5863222

Crabos, M; Fabbro, D; Imber, R; Woodtli, T; Erne, P ^[1]

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1. Univ. Hospital, Basel (Switzerland)

Protein kinase C (PKC) is an important intraplatelet second messenger which is activated and translocated from cytosol to membrane in response to extracellular stimuli. Molecular cloning revealed that PKC represents a family of closely related subspecies. Immunoblot analysis using monoclonal antibodies specific for {alpha}, {beta}, and {gamma} and polyclonal antibodies specific for the {delta}, {epsilon}, and {zeta} subspecies revealed the presence of {alpha}, {beta}, and {zeta} isoforms in human platelets. The subcellular distribution of {alpha}, {beta} and {zeta} in resting state was in the range of 80% in cytosol and 20% in membrane. After 2 min incubation of platelets with 300 nM TPA there was an increase of 10% of {beta} and {zeta} subspecies in membrane whereas incubation after one hour incubation with TPA about 70% of all isoforms were associated with the membrane. Incubation of platelets with 1mM of CaCl{sub 2} for 10 min prior to stimulation with 100 nM TPA for 30 min resulted in an increase in the membrane of: 31{plus minus}1 for {alpha}, 30{plus minus}1 for {beta} and 36{plus minus}6 for {zeta}, while in the presence of 1mM EDTA the increase was 14{plus minus}2 for {alpha}, 28{plus minus}1 for {beta} and 34{plus minus}1 for {zeta} (mean %{plus minus}sem). These results demonstrate the presence of three different subtypes of PKC in human platelets which display different time courses of translocation and different sensitivity to external calcium with respect to TPA. This suggest that these isoforms can be activated differently with hormones and may be involved in different intracellular pathways.

• OSTI ID: 5863222
• Report Number(s): CONF-9104107--
• Conference Information: Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Journal Volume: 5:4
• Country of Publication: United States
• Language: English

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560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH METALS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BIOLOGICAL PATHWAYS
BLOOD
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ORGANIC COMPOUNDS
PHORBOL ESTERS
PHOSPHORUS-GROUP TRANSFERASES
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SUBCELLULAR DISTRIBUTION
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