Vasopressin rapidly stimulates protein kinase C in digitonin‐permeabilized swiss 3T3 cells: Involvement of a pertussis toxin‐insensitive guanine nucleotide binding protein

Jorge D. Erusalimsky, Enrique Rozengurt*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

Guanine nucleotides and pertussis toxin were used to test for the involvement of a guanine nucleotide binding protein in the vasopressin V1 receptor‐mediated stimulation of protein kinase C activity in Swiss 3T3 cells. Addition of vasopressin in the presence of [γ‐32P]ATP and digitonin caused a marked and rapid increase (8 ± 1‐fold after 1 min) in the phosphorylation of an Mr = 80,000 cellular protein (80K), a specific marker for protein kinase C activation. This phosphorylation was selectively blocked by the V1 receptor antagonist Pmp1‐0‐Me‐Tyr2 [Arg8]vasopressin, indicating that the effect was mediated through the vasopressin V1 receptor. Down regulation of protein kinase C by prior prolonged pretreatment of intact cells with phorbol 12, 13‐dibutyrate (PBt2) blocked the ability of vasopressin to stimulate the phosphorylation of 80K in digitonin‐permeabilized cells. Addition of a submaximal concentration of vasopressin together with the GTP analogue GTP‐γ‐S caused a synergistic stimulation of 80K phosphorylation. The GDP analogue GDP‐β‐S caused a 50% inhibition of the phosphorylation of 80K induced by a saturating concentration of vasopressin and shifted the vasopressin dose‐response curve to the right. GDP‐β‐S had no effect on the dose‐response for the stimulation of 80K phosphorylation induced by PBt2. Prior incubation of intact quiescent cultures of Swiss 3T3 cells with pertussis toxin did not impair either vasopressin‐induced increase in cytosolic [Ca2+] or activation of protein kinase C. These findings provide functional evidence for the involvement of a pertussis toxin‐insesitive G protein in the vasopressin V1 receptor‐mediated stimulation of protein kinase C in Swiss 3T3 cells.

Original languageEnglish
Pages (from-to)253-261
Number of pages9
JournalJournal of Cellular Physiology
Volume141
Issue number2
DOIs
Publication statusPublished - Nov 1989
Externally publishedYes

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