TY - JOUR
T1 - Regulation of purified subtypes of phosphatidylinositol-specific phospholipase C β by G protein α and βγ subunits
AU - Smrcka, Alan V.
AU - Sternweis, Paul C.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1993/5/5
Y1 - 1993/5/5
N2 - Specific antisera were produced to peptides representing the carboxyl termini of three subtypes of phosphatidylinositol-specific phospholipase C (PIPLC) β 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 β3 is present in a variety of cell lines and rat tissues, whereas the distribution of PIPLC β1 and β2 is more restricted. A combination of conventional and immunoaffinity chromatographic techniques was used to purify PIPLC β1 and β3 from rat brain membranes. PIPLC β2 was purified from cytosol of HL60 cells. All three subtypes were activated by purified G protein αq/11 subunits with the following relative efficacies: PIPLC β3 ≥ PIPLC β1 ≫ PIPLC β2. All three PIPLC subtypes were also activated by G protein βγ subunits with varying efficacies. The presence of βγ subunits depressed the ability of αq/11 to activate PIPLC β1 and β3 at low Mg2+ concentrations (1 mM). At higher concentrations of Mg2+ (2 mM or greater), activation of PIPLC β3, but not PIPLC β1, by βγ and αq/11 became additive. PIPLC β3 was activated by αq/11 even in the presence of a saturating concentration of βγ 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+.
AB - Specific antisera were produced to peptides representing the carboxyl termini of three subtypes of phosphatidylinositol-specific phospholipase C (PIPLC) β 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 β3 is present in a variety of cell lines and rat tissues, whereas the distribution of PIPLC β1 and β2 is more restricted. A combination of conventional and immunoaffinity chromatographic techniques was used to purify PIPLC β1 and β3 from rat brain membranes. PIPLC β2 was purified from cytosol of HL60 cells. All three subtypes were activated by purified G protein αq/11 subunits with the following relative efficacies: PIPLC β3 ≥ PIPLC β1 ≫ PIPLC β2. All three PIPLC subtypes were also activated by G protein βγ subunits with varying efficacies. The presence of βγ subunits depressed the ability of αq/11 to activate PIPLC β1 and β3 at low Mg2+ concentrations (1 mM). At higher concentrations of Mg2+ (2 mM or greater), activation of PIPLC β3, but not PIPLC β1, by βγ and αq/11 became additive. PIPLC β3 was activated by αq/11 even in the presence of a saturating concentration of βγ 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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M3 - Article
C2 - 8387502
AN - SCOPUS:0027214868
SN - 0021-9258
VL - 268
SP - 9667
EP - 9674
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 13
ER -