Novel bimodal effects of the G-protein tissue transglutaminase on adrenoreceptor signalling

Jianwen Zhang, Janusz Tucholski, Mathieu Lesort, Richard S. Jope, Gail V.W. Johnson

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Tissue transglutaminase (tTG) is a novel G-protein that previous studies showed can couple ligand-bound activated α(1B) adrenoreceptors to phospholipase C-δ, resulting in phosphoinositide (PI) hydrolysis. In human neuroblastoma SH-SY5Y cells we found that although endogenous tTG can facilitate α(1B) adrenoreceptor-stimulated PI hydrolysis, its contribution is minor compared with the classical heterotrimeric G-protein G(q/11). Further, we show that the α(1B) adrenoreceptor recruits tTG to the membrane and that this recruitment is enhanced by agonist occupancy of the receptor. In addition, the effects of tTG on signalling are bimodal. At low expression levels, tTG enhanced α(1B) adrenoreceptor-stimulated PI hydrolysis, whereas at higher expression levels tTG attenuated significantly this response. These findings are the first to demonstrate that a protein can both facilitate and attenuate receptor-stimulated PI hydrolysis.

Original languageEnglish (US)
Pages (from-to)541-549
Number of pages9
JournalBiochemical Journal
Volume343
Issue number3
DOIs
StatePublished - Nov 1 1999

Keywords

  • α(1B) adrenoreceptors
  • Phosphoinositide hydrolysis
  • Phospholipase C
  • SH-SY5Y cells

ASJC Scopus subject areas

  • Biochemistry

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