Receptor-tyrosine-kinase- and G beta gamma-mediated MAP kinase activation by a common signalling pathway.

Published

Journal Article

Mitogen-activated protein (MAP) kinases mediate the phosphorylation and activation of nuclear transcription factors that regulate cell growth. MAP kinase activation may result from stimulation of either tyrosine-kinase (RTK) receptors, which possess intrinsic tyrosine kinase activity, or G-protein-coupled receptors (GPCR). RTK-mediated mitogenic signalling involves a series of SH2- and SH3-dependent protein-protein interactions between tyrosine-phosphorylated receptor, Shc, Grb2 and Sos, resulting in Ras-dependent MAP kinase activation. The beta gamma subunits of heterotrimeric G proteins (G beta gamma) also mediate Ras-dependent MAP kinase activation by an as-yet unknown mechanism. Here we demonstrate that activation of MAP kinase by Gi-coupled receptors is preceded by the G beta gamma-mediated tyrosine phosphorylation of Shc, leading to an increased functional association between Shc, Grb2 and Sos. Moreover, disruption of the Shc-Grb2-Sos complex blocks G beta gamma-mediated MAP kinase activation, indicating that G beta gamma does not mediate MAP kinase activation by a direct interaction with Sos. These results indicate that G beta gamma-mediated MAP kinase activation is initiated by a tyrosine phosphorylation event and proceeds by a pathway common to both GPCRs and RTKs.

Full Text

Duke Authors

Cited Authors

  • van Biesen, T; Hawes, BE; Luttrell, DK; Krueger, KM; Touhara, K; Porfiri, E; Sakaue, M; Luttrell, LM; Lefkowitz, RJ

Published Date

  • August 31, 1995

Published In

Volume / Issue

  • 376 / 6543

Start / End Page

  • 781 - 784

PubMed ID

  • 7651538

Pubmed Central ID

  • 7651538

International Standard Serial Number (ISSN)

  • 0028-0836

Digital Object Identifier (DOI)

  • 10.1038/376781a0

Language

  • eng

Conference Location

  • England