A G-protein beta gamma-subunit-responsive phosphoinositide 3-kinase activity in human platelet cytosol.

Journal Article (Journal Article)

Thrombin activates phosphoinositide 3-kinase (PI 3-kinase) in platelets via a mechanism involving G-proteins, possibly of both the heterotrimeric and the low molecular weight families. We have investigated the regulation of PI 3-kinase present in platelet cytosol, and we show that this activity can be stimulated by a mixed preparation of G-protein beta gamma-subunits. This stimulation is reversed by preincubation of the beta gamma-subunits with GDP-liganded alpha-subunits. The beta gamma-stimulated activity is inhibited by wortmannin, a recently identified inhibitor of PI 3-kinase in other systems. In addition, the activity associates with PDGF receptor phosphotyrosyl peptide and monoclonal antibody designed to interact with the p85 subunit of PI 3-kinase. We suggest that this beta gamma-sensitive activity is related to previously identified forms of PI 3-kinase.

Full Text

Duke Authors

Cited Authors

  • Thomason, PA; James, SR; Casey, PJ; Downes, CP

Published Date

  • June 17, 1994

Published In

Volume / Issue

  • 269 / 24

Start / End Page

  • 16525 - 16528

PubMed ID

  • 8206965

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng

Conference Location

  • United States