Influence of γ subunit prenylation on association of guanine nucleotide-binding regulatory proteins with membranes

Kathryn H. Muntz, Paul C. Sternweis, Alfred G. Gilman, Susanne M. Mumby

Research output: Contribution to journalArticlepeer-review

118 Scopus citations


Two approaches were taken to address the possible role of γ-subunit prenylation in dictating the cellular distribution of guanine nucleotide-binding regulatory proteins. Prenylation of γ subunits was prevented by site-directed mutagenesis or by inhibiting the synthesis of mevalonate, the precursor of cellular isoprenoids. When β or γ subunits were transiently expressed in COS-M6 simian kidney cells (COS) cells, the proteins were found in the membrane fraction by immunoblotting. Immunofluorescence experiments indicated that the proteins were distributed to intracellular structures in addition to plasma membranes. Replacement of Cys68 of γ with Ser prevented prenylation of the mutant protein and association of the protein with the membrane fraction of COS cells. Immunoblotting results demonstrated that some of the β subunits were found in the cytoplasm when coexpressed with the nonprenylated mutant γ subunit. When Neuro 2A cells were treated with compactin to inhibit protein prenylation, a fraction of endogenous β and γ was distributed in the cytoplasm. It is concluded that prenylation facilitates association of γ subunits with membranes, that the cellular location of γ influences the distribution of β, and that prenylation is not an absolute requirement for interaction of β and γ.

Original languageEnglish (US)
Pages (from-to)49-61
Number of pages13
JournalMolecular biology of the cell
Issue number1
StatePublished - 1992

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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