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Regulation of purified subtypes of phosphatidylinositol-specific phospholipase C beta by G protein alpha and beta gamma subunits.

Authors: Smrcka, AV  Sternweis, PC 
Citation: Smrcka AV and Sternweis PC, J Biol Chem. 1993 May 5;268(13):9667-74.
Pubmed: (View Article at PubMed) PMID:8387502

Specific antisera were produced to peptides representing the carboxyl termini of three subtypes of phosphatidylinositol-specific phospholipase C (PIPLC) beta which have been identified by isolation of cDNAs (Kriz, R., Lin, L., Sultzman, L., Ellis, C., Heldin, C., Pawson, T., and Knopf, J. (1990) Ciba Found. Symp. 150, 112-127). Screening with the antisera indicates that PIPLC beta 3 is present in a variety of cell lines and rat tissues, whereas the distribution of PIPLC beta 1 and beta 2 is more restricted. A combination of conventional and immunoaffinity chromatographic techniques was used to purify PIPLC beta 1 and beta 3 from rat brain membranes. PIPLC beta 2 was purified from cytosol of HL60 cells. All three subtypes were activated by purified G protein alpha q/11 subunits with the following relative efficacies: PIPLC beta 3 > or = PIPLC beta 1 >> PIPLC beta 2. All three PIPLC subtypes were also activated by G protein beta gamma subunits with varying efficacies. The presence of beta gamma subunits depressed the ability of alpha q/11 to activate PIPLC beta 1 and beta 3 at low Mg2+ concentrations (1 mM). At higher concentrations of Mg2+ (2 mM or greater), activation of PIPLC beta 3, but not PIPLC beta 1, by beta gamma and alpha q/11 became additive. PIPLC beta 3 was activated by alpha q/11 even in the presence of a saturating concentration of beta gamma subunits. This indicates that there are separate sites for interaction of PIPLCs with G protein subunits and that this interaction differs depending on the enzyme subtype and the concentration of Mg2+.


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RGD Object Information
RGD ID: 11535163
Created: 2016-09-21
Species: All species
Last Modified: 2016-09-21
Status: ACTIVE


RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.