G-protein inhibition of phospholipase C-β1 in membranes: Role of G-protein βγ subunits

Irene Litosch

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Rat liver plasma membranes reconstituted with bovine brain phospholipase C β1 (PLC-β1) exhibit a dual regulation of PLC-β1 activity by G-proteins. Guanosine 5'-[γ-thio] triphosphate (GTP[S]; 0.1 nM) produced a 20-25% inhibition of PLC-β1 activity within 7 min of incubation. The addition of vasopressin resulted in near-basal levels of activity in the presence of 0.1 nM GTP[S]. Clonidine had little effect on the net inhibition due to GTP[S]. A similar antagonism between carbachol and GTP[S] occurred in cerebral cortical membranes containing endogenous PLC-β1 activity. α(o/i)-GDP (a mixture of GDP-liganded G(oα) and G(iα)) attenuated the GTP[S]-dependent inhibition of PLC-β1 whereas α(o/i)-GTP[S] had no effect, suggesting an involvement of G-protein βγ subunits in the inhibition of PLC-β1. Low concentrations of βγ subunits inhibited PLC-β1 activity. Inhibition was followed by reversal to basal activity and onset of stimulation as the βγ concentration was increased. Inhibition by βγ was dependent on the presence of membranes. These results indicate that G-protein βγ subunits constitute a mechanism by which G-proteins mediate a rapid and transient inhibition of PLC-β1.

Original languageEnglish (US)
Pages (from-to)173-178
Number of pages6
JournalBiochemical Journal
Issue number1
StatePublished - 1996
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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