Abstract
Protein kinase C (PKC) isoforms phosphorylated phospholipase C-β1 (PLC-β1) in vitro as follows: PKCα >> PKCε; not PKCζ. PLC-β3 was not phosphorylated by PKCα. G-protein βγ subunits inhibited the PKCα phosphorylation of PLC-β1 in a concentration-dependent manner. Half-maximal inhibition occurred with 500nM βγ. G-protein βγ subunits also antagonized the PKCα-mediated inhibition of PLC-β1 enzymic activity. PKCα, in turn, inhibited the stimulation of PLC-β1 activity by βγ. There was little effect of PKCα on the stimulation of PLC-β1 by α(q/11)-guanosine 5'[γ-thio]triphosphate (GTP[S]). These findings demonstrate that G protein βγ subunits antagonize PKCα regulation of PLC-β1. Thus βγ subunits might have a role in modulating the negative feedback regulation of this signalling system by PKC.
Original language | English (US) |
---|---|
Pages (from-to) | 701-707 |
Number of pages | 7 |
Journal | Biochemical Journal |
Volume | 326 |
Issue number | 3 |
DOIs | |
State | Published - Sep 15 1997 |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology