FEBS Letters | |
The activation of protein kinase C by the polyphosphoinositides phosphatidylinositol 4,5‐diphosphate and phosphatidylinositol 4‐monophosphate | |
Weinstein, I.Bernard1  O'Brian, Catherine A.1  Arthur, W.Lane2  | |
[1] Cancer Center and Institute of Cancer Research, Columbia University, 701 W. 168th St., New York, NY 10032, USA;Department of Genetics, Columbia University, 701 W. 168th St., New York, NY 10032, USA | |
关键词: Protein kinase C; Polyphosphoinositide; Tumor promoter; Lipid cofactor; DMSO; dimethylsulfoxide; PI; phosphatidylinositol; PI 4P; L-α-phosphatidylinositol 4-monophosphate; PI 4; 5DP; L-α-phosphatidylinositol 4; 5-diphosphate; PKC; protein kinase C; PMSF; phenylmethylsulfonyl fluoride; PS; phosphatidylserine; TPA; 12-O-tetradecanoylphorbol-13-acetate; | |
DOI : 10.1016/0014-5793(87)80083-2 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Protein kinase C(PKC) is a Ca2+- and phospholipid-dependent protein kinase which can be activated by diacylglycerol, a product of polyphosphoinositide hydrolysis. In this report, we show that the polyphosphoinositides L-α-phosphatidylinositol 4-monophosphate (PI 4P) and L-α-phosphatidylinositol 4,5-diphosphate (PI 4,5DP) can serve as phospholipid cofactors of isolated rat brain PKC. The order of potency of the phosphoinositides in the activation of PKC, PI > PI 4P > PI 4,5DP, shows a negative correlation with the degree of acidity of the phospholipid head group, whether 1 mM Ca2+ or 200 nM TPA is present in the reaction assay mixture. Although the polyphosphoinositides are by themselves weaker activators of PKC than PI, small amounts of PI 4,5DP cause a two-fold enhancement of PKC in the presence of Ca2+ and PI. While the endogenous phospholipid cofactors of PKC remain to be identified, these results suggest that the small amounts of polyphosphoinositides which are present in cell membranes may play a direct role in the activation of PKC in vivo, by serving as phospholipid cofactors of the enzyme.
【 授权许可】
Unknown
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