Autoacylation of G Protein α Subunits*
- From the Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75235
Abstract
The palmitoylation or S-acylation of at least some G protein α subunits is a dynamic process that is regulated in vivo by the activation of associated receptors. Highly purified, myristoylated Giα1 and other G protein α subunits react spontaneously with palmitoyl-CoA in vitro to form thioesterified proteins. This reaction requires native Giα1 and occurs exclusively at Cys3, the same residue that is palmitoylated in vivo. The reaction proceeds to completion, and its rate is roughly equal to the rate of loss of palmitate observed in pulse-chase experiments in vivo. The rate of autoacylation is significantly enhanced by the G protein βγ subunit complex. Autoacylation may play a role in the dynamic thioesterification of some cellular proteins.
Footnotes
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↵‡ Department of Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75235.
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↵* This work was supported by National Institutes of Health Grant GM34497 and Predoctoral Training Grant T32 GM07062 and the Raymond and Ellen Willie Chair of Molecular Neuropharmacology. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵1 The abbreviations used are:
- GTPγS
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guanosine 5′-3-O-(thio)triphosphate
- CHES
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2[N-cyclohexylamino]ethane sulfonic acid.
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↵2 C. Kleuss and A. G. Gilman, unpublished observations.
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- Received May 23, 1996.
- Revision received July 11, 1996.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
