Lipid modifications of G proteins: α Subunits are palmitoylated

Maurine E. Linder, Pamela Middleton, John R. Hepler, Ronald Taussig, Alfred G. Gilman, Susanne M. Mumby

Research output: Contribution to journalArticle

278 Scopus citations

Abstract

A small number of membrane-associated proteins are reversibly and covalently modified with palmitic acid. Palmitoylation of G-protein α and β subunits was assessed by metabolic labeling of subunits expressed in simian COS cells or insect Sf9 cells. The fatty acid was incorporated into all of the α subunits examined (α(s), α(o), α(i1), α(i2), α(i3), α(z), and α(q)), including those that are also myristoylated (α(o), α(i), and α(z)). Palmitate was released by treatment with base, suggesting attachment to the protein through a thioester or ester bond. Limited tryptic digestion of activated α(o) and α(s) resulted in release of the amino-terminal portions of the proteins and radioactive palmitate. These data are consistent with palmitoylation of the proteins near their amino termini, most likely on Cys-3. Reversible acylation of G-protein α subunits may provide an additional mechanism for regulation of signal transduction.

Original languageEnglish (US)
Pages (from-to)3675-3679
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume90
Issue number8
DOIs
StatePublished - Jan 1 1993

ASJC Scopus subject areas

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