Isoprenylation of the G protein gamma subunit is both necessary and sufficient for beta gamma dimer-mediated stimulation of phospholipase C

Alexander Dietrich, Derek Brazil, Ole N. Jensen, Michael Meister, Marion Schrader, John F. Moomaw, Matthias Mann, Daria Illenberger, Peter Gierschik*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

We have previously shown that isoprenylation and/or additional post-translational processing of the G protein γ1 subunit carboxyl terminus is required for β1γ1 subunit stimulation of phospholipase C-β2 (PLCβ2) [Dietrich, A., Meister, M., Brazil, D., Camps, M., & Gierschik, P. (1994) Eur. J. Biochem. 219, 171−178]. To examine whether isoprenylation of the γ1 subunit alone is sufficient for β1γ1-mediated PLCβ2 stimulation or whether any of the two subsequent modifications, proteolytic removal of the carboxyl-terminal tripeptide and/or carboxylmethylation, is required for this effect, nonisoprenylated recombinant β1γ1 dimers were produced in baculovirus-infected insect cells, purified to near homogeneity, and then isoprenylated in vitro using purified recombinant protein farnesyltransferase. Analysis of the β1γ1 dimer after in vitro farnesylation by reversed phase high-performance liquid chromatography followed by delayed extraction matrix-assisted laser desorption/ionization mass spectrometry confirmed that the γ1 subunit was carboxyl-terminally farnesylated but not proteolyzed and carboxylmethylated. Functional reconstitution of in vitro-farnesylated β1γ1 dimers with a recombinant PLCβ2 isozyme revealed that farnesylation rendered recombinant nonisoprenylated β1γ1 dimers capable of stimulating PLCβ2 and that the degree of this stimulation was only approximately 45% lower for in vitro-farnesylated β1γ1 dimers than for fully modified native β1γ1 purified from bovine retinal rod outer segments. Taken together, these results suggest that isoprenylation of the γ subunit is both necessary and sufficient for βγ dimer-mediated stimulation of phospholipase C.

Original languageEnglish
Pages (from-to)15174-15182
Number of pages9
JournalBiochemistry
Volume35
Issue number48
DOIs
Publication statusPublished - 03 Dec 1996
Externally publishedYes

Fingerprint

Dive into the research topics of 'Isoprenylation of the G protein gamma subunit is both necessary and sufficient for beta gamma dimer-mediated stimulation of phospholipase C'. Together they form a unique fingerprint.

Cite this