THE ACTIN-BINDING PROTEIN PROFILIN BINDS TO PIP2 AND INHIBITS ITS HYDROLYSIS BY PHOSPHOLIPASE-C
THE ACTIN-BINDING PROTEIN PROFILIN BINDS TO PIP2 AND INHIBITS ITS HYDROLYSIS BY PHOSPHOLIPASE-C
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DOI：
10.1126/science.2157283
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发表时间：
1990-03-30
期刊：
影响因子：
56.9
通讯作者：
POLLARD, TD
中科院分区：
文献类型：
--
作者：
GOLDSCHMIDTCLERMONT, PJ;MACHESKY, LM;POLLARD, TD
普遍认为叶酸蛋白会调节肌动蛋白聚合，但是观察到酸性磷脂可以解离叶片蛋白和肌动蛋白的络合物，这增加了叶酸蛋白酶也可能调节脂质代谢的可能性。从血小板中分离出的叶酸蛋白具有高亲和力与胶束中的磷脂酰肌醇4,5-双磷酸（PIP2）分子的小簇，以及其他具有其他磷脂的双层。在纯PIP2的胶束中，pip2酸蛋白复合蛋白的摩尔比为1：7，在大部分由其他磷脂组成的双层中，双层中的摩尔比为1：5。 Profilin与血小板胞质磷酸肌醇特异性磷脂酶C与PIP2底物的相互作用有效竞争，从而抑制该酶的PIP2水解。这些分子的细胞浓度和结合特性与profilin是磷酸肌醇信号传导途径的负调节剂一致，除了其确定的功能是肌动蛋白聚合的抑制剂。
Profilin is generally thought to regulate actin polymerization, but the observation that acidic phospholipids dissociate the complex of profilin and actin raised the possibility that profilin might also regulate lipid metabolism. Profilin isolated from platelets binds with high affinity to small clusters of phosphatidylinositol 4,5-bisphosphate (PIP2) molecules in micelles and also in bilayers with other phospholipids. The molar ratio of the complex of profilin with PIP2 is 1:7 in micelles of pure PIP2 and 1:5 in bilayers composed largely of other phospholipids. Profilin competes efficiently with platelet cytosolic phosphoinositide-specific phospholipase C for interaction with the PIP2 substrate and thereby inhibits PIP2 hydrolysis by this enzyme. The cellular concentrations and binding characteristics of these molecules are consistent with profilin being a negative regulator of the phosphoinositide signaling pathway in addition to its established function as an inhibitor of actin polymerization.