| Autor: |
Illenberger, Daria, Schwald, Frieder, Gierschik, Peter |
| Předmět: |
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| Zdroj: |
European Journal of Biochemistry; 5/15/97, Vol. 246 Issue 1, p71-77, 7p |
| Abstrakt: |
Members of the Β isozyme subfamily of phosphatidylinositol-specific phospholipase C (PLC) are stimulated by α subunits and Βγ dimers of heterotrimeric guanine-nucleotide-binding proteins (G proteins). Myeloid differentiated human HL-60 granulocytes and bovine neutrophils contain a soluble phospholipase C, which is stimulated by the metabolically stable GTP analogue guanosine (5'→O)-3-thiotriphosphate (GTP[S]). To identify the component(s) involved in mediating this stimulation, the relevant polypeptide(s) was resolved from endogenous phospholipase C and purified from bovine neutrophil cytosol by measuring its ability to confer GTP[S] stimulation to exogenous recombinant PLCΒ2. The resolved factor, which behaved as 48-kDa protein upon gel filtration, stimulated PLCΒ2 but not PLCΒ1, or PLCδ. Activation of phosphatidylinositol 4-phosphate 5-kinase was not involved in this stimulation. The purified stimulatory factor consisted of two polypeptides of molecular masses of approximately 23 kDa and 26 kDa. The protein stimulated a deletion mutant of PLCΒ2 that lacked a carboxyl-terminal region necessary for stimulation by members of the αq subfamily of the G-protein α subunits. The results of this study suggest that a GTP-binding protein distinct from αq subunits, probably a low-molecular-mass GTP-binding protein associated with a regulatory protein, is involved in isozyme-specific activation of αq. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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