Protein kinase C phosphorylates the inhibitory guanine‐nucleotide‐binding regulatory component and apparently suppresses its function in hormonal inhibition of adenylate cyclase

T. Katada, A. G. Gilman, Y. Watanabe, S. Bauer, K. H. Jakobs

Research output: Contribution to journalArticlepeer-review

508 Scopus citations

Abstract

Human platlet membrane proteins were phosphorylated by exogenous, partially purified Ca2+‐activated phospholipid‐dependent protein kinase (protein kinase C. the phosphorylation of one of the major substrates fro protein kinase C (Mr= 41000) wa specifically suppressed by the β subunit of the inhibitory guaninenucleotide‐binding regulatory component (G1, Ni) of adenylate cyclase. The free α subunit of Gi (Mr= 41000) also served as an excellent substrate for the kinase (<0.5 mol phosphate incorporated per mol of subunit), but the Gi oligomer (α·β·γ) did not. Treatment of cyc S49 lymphoma cells, which are dificient in Gs/Ns(the stimulatory component) but contain functional Gi/Ns, with the phorbol ester, 12‐O‐tetradecanoylophorbol 13‐acetate, a potent activator of protein kinase C, did not alter stimulation of adenylate cyclase catalystic activity by forskolin, whereas the Gi/Ni‐mediated inhibition of the cyclase by the hormone, somatostatin, was impaired in these membranes. The results suggest that the α subunit of the inhibitory guanine‐nucleotide‐binding regulatory component of adenylate cyclase may be a physiological substrate for protein kinase C and that the function of the component in transducing inhibitory hormonal signals to adenylate cyclase is altered by its phosphorylation.

Original languageEnglish (US)
Pages (from-to)431-437
Number of pages7
JournalEuropean Journal of Biochemistry
Volume151
Issue number2
DOIs
StatePublished - Sep 1985

ASJC Scopus subject areas

  • Biochemistry

Fingerprint Dive into the research topics of 'Protein kinase C phosphorylates the inhibitory guanine‐nucleotide‐binding regulatory component and apparently suppresses its function in hormonal inhibition of adenylate cyclase'. Together they form a unique fingerprint.

Cite this