Involvement of protein tyrosine phosphatases in activation of the trimeric G protein G(q/11)

Hisashi Umemori, Takashi Hayashi, Takafumi Inoue, Shigetada Nakanishi, Katsuhiko Mikoshiba, Tadashi Yamamoto

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

A variety of receptors coupled to the heterotrimeric guanine nucleotide-binding protein G(q/11) stimulate intracellular Ca2+ release through inositol (1,4,5)-trisphosphate (IP3) formation. We previously reported that tyrosine phosphorylation of the α subunit of the G(q/11) protein by protein tyrosine kinases (PTKs) regulates the activation of G(q/11) protein. Here we show that protein tyrosine phosphatases (PTPs) are also essential for G(q/11) protein activation. We find that G(q/11) protein-coupled receptor-mediated formation of IP3 is blocked by PTP inhibitors as well as PTK inhibitors. These inhibitors act prior to G(q/11) protein activation. Tyrosine phosphorylation of the α subunit of G(q/11) appears to inhibit its interaction with receptors. Thus, PTP is required for controlling the level of tyrosine phosphorylation of the α subunit of G(q/11) to promote its interaction with receptors. Therefore, we conclude that PTKs and PTPs co-operate to proceed activation cycle of the G(q/11) protein through tyrosine phosphorylation and de-phosphorylation of the α subunit of G(q/11).

Original languageEnglish
Pages (from-to)7399-7402
Number of pages4
JournalOncogene
Volume18
Issue number51
DOIs
Publication statusPublished - 1999 Dec 2
Externally publishedYes

Keywords

  • G protein
  • Gα(q/11)
  • IP3
  • Metabotropic glutamate receptor
  • Tyrosine phosphatase
  • Tyrosine phosphorylation

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

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  • Cite this

    Umemori, H., Hayashi, T., Inoue, T., Nakanishi, S., Mikoshiba, K., & Yamamoto, T. (1999). Involvement of protein tyrosine phosphatases in activation of the trimeric G protein G(q/11). Oncogene, 18(51), 7399-7402. https://doi.org/10.1038/sj.onc.1203152