G-protein βγ dimers: Membrane targeting requires subunit coexpression and intact γ C-A-A-X domain

William F. Simonds, James E. Butrynski, Narasimhan Gautam, Cecilia G. Unson, Allen M. Spiegel

Research output: Contribution to journalArticlepeer-review

196 Scopus citations


Attachment of heterotrimeric G-proteins to the inner face of the plasma membrane is fundamental to their role as signal transducers by allowing interaction with both receptors and effectors. Certain G-protein α subunits are anchored to the membrane by covalent myristoylation. The βγ complex is required for G-protein interaction with receptors and is independently membrane associated through an unknown mechanism. A series of carboxyl-terminal modifications including isoprenylation which may contribute to membrane attachment has been identified recently in G-protein γ subunits. Expression and membrane targeting of β and γ subunits were examined in COS cells. The expression of either subunit was found to require cotransfection with both β and γ cDNAs. Mutation of the carboxyl-terminal cysteine residue of γ shown to undergo isoprenylation and carboxymethyl-esterification preserved βγ expression but blocked isoprenylation and membrane attachment. These results implicate the carboxyl-terminal processing of G-protein γ subunits and β coexpression as necessary and sufficient for membrane targeting of the βγ complex.

Original languageEnglish (US)
Pages (from-to)5363-5366
Number of pages4
JournalJournal of Biological Chemistry
Issue number9
StatePublished - 1991
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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