Members of the G_q α Subunit Gene Family Activate Phospholipase C β Isozymes
Abstract
The relative specificities of members of the Gα_q family of GTP-binding proteins were tested for their ability to activate different phosphoinositide-specific phospholipase C (PI-PLC) β isozymes. Cos-7 cells were transfected with cDNA corresponding to Gα_q, Gα_(11), Gα_(14), and Gα_(16). Most of the recombinant protein was bound to the cell membrane and these membranes were washed to elute endogenous PI-PLC activity. The membrane preparation was reconstituted with purified preparations of the PI-PLC β isozymes and guanosine 5'-O-thiotriphosphate (GTPyS)-stimulated enzyme activity was measured. All four proteins of the Gα_q family were found to stimulate PI-PLC β1, with Gα_q and Gα_(11) being most efficient. On the other hand, Gα_(16) was found to most effectively activate PI-PLC β2, while Gα_q, Gα_(11), and Gα_(14) showed less stimulation. Specific anti- Gα_(16) antibody blocked the stimulation of both PI-PLC β1 and PI-PLC β2 in the enriched membrane fraction. We conclude that there is specificity in the interaction of different members of the G_q family with different PI-PLC β effectors. This specificity may be important in generating tissue- or receptor-specific responses in vivo.
Additional Information
© 1992 American Society for Biochemistry and Molecular Biology. Received for publication, April 8, 1992.This work was supported by National Institutes of Health Grant GM 34236. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore he hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.Additional details
- Eprint ID
- 29904
- Resolver ID
- CaltechAUTHORS:20120330-065437671
- GM 34236
- NIH
- Created
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2012-03-30Created from EPrint's datestamp field
- Updated
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2019-10-03Created from EPrint's last_modified field