Turkey erythrocyte membranes as a model for regulation of phospholipase C by guanine nucleotides.

摘要: Phosphoinositides of human, rabbit, rat, and turkey erythrocytes were radiolabeled by incubation intact cells with [32P]Pi. Guanosine 5'-O-(thiotriphosphate) (GTP gamma S) NaF, which are known activators guanine nucleotide regulatory proteins, caused a large increase in [32P]inositol phosphate release from plasma membranes derived erythrocytes, but had no effect on inositol formation prepared the mammalian erythrocytes. High performance liquid chromatography analysis indicated that bisphosphate, 1,3,4-trisphosphate, 1,4,5-trisphosphate, 1,3,4,5-tetrakisphosphate all increased 20-30-fold during 10-min erythrocyte GTP S. The was accompanied similar decrease radioactivity phosphatidylinositol 4-phosphate (PIP) 4,5-bisphosphate (PIP2). S K0.5 600 nM; guanosine 5'-(beta, gamma-imido)trisphosphate 50-75% as efficacious expressed 36 microM. Although alone little formation, it blocked S-stimulated did 5'-O-(2-thiodiphosphate). Turkey also shown to express synthetase activity [3H] resulted incorporation radiolabel into phosphatidylinositol, PIP, PIP2. Incubation [3H]inositol-labeled increases corresponding decreases PIP data suggest that, contrast expresses nucleotide-binding protein regulates phospholipase C, such, should provide useful model system for furthering our understanding hormonal regulation this enzyme.