G protein gamma subunits contain a 20-carbon isoprenoid.

Journal Article (Journal Article)

A small subset of cellular proteins are covalently modified by the addition of isoprenoid groups. These include p21ras, fungal mating factors, and nuclear lamins, which are isoprenylated at carboxyl-terminal cysteine residues with a 15-carbon farnesyl group. The similarity of the carboxyl-terminal sequences of these proteins with the alpha and gamma subunits of signal-transducing guanine nucleotide-binding regulatory proteins (G proteins) prompted examination of isoprenylation of G protein subunits. PC-12 cells were incubated with the isoprenoid precursor [3H]mevalonolactone. The beta and gamma subunits were isolated by specific association with an affinity column of immobilized alpha subunits. The gamma subunits were radiolabeled, and the tritiated lipid released from them by treatment with methyl iodide comigrated chromatographically with the 20-carbon isoprenoid geranylgeraniol. Label was not detected in G protein alpha or beta subunits. Isoprenylation of gamma subunits by the geranylgeranyl group is presumed to contribute to the association of G proteins with membranes.

Full Text

Duke Authors

Cited Authors

  • Mumby, SM; Casey, PJ; Gilman, AG; Gutowski, S; Sternweis, PC

Published Date

  • August 1990

Published In

Volume / Issue

  • 87 / 15

Start / End Page

  • 5873 - 5877

PubMed ID

  • 2116011

Pubmed Central ID

  • PMC54431

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.87.15.5873


  • eng

Conference Location

  • United States