Otsu M, Hiles I, Gout I, Fry M J, Ruiz-Larrea F, Panayotou G, Thompson A, Dhand R, Hsuan J, Totty N
Ludwig Institute for Cancer Research, London, England.
Cell. 1991 Apr 5;65(1):91-104. doi: 10.1016/0092-8674(91)90411-q.
Affinity-purified bovine brain phosphatidylinositol 3-kinase (PI3-kinase) contains two major proteins of 85 and 110 kd. Amino acid sequence analysis and cDNA cloning reveals two related 85 kd proteins (p85 alpha and p85 beta), which both contain one SH3 and two SH2 regions (src homology regions). When expressed, these 85 kd proteins bind to and are substrates for tyrosine-phosphorylated receptor kinases and the polyoma virus middle-T antigen/pp60c-src complex, but lack PI3-kinase activity. However, an antiserum raised against p85 beta immunoprecipitates PI3-kinase activity. The active PI3-kinase complex containing p85 alpha or p85 beta and the 110 kd protein binds to PDGF but not EGF receptors. p85 alpha and p85 beta may mediate specific PI3-kinase interactions with a subset of tyrosine kinases.
亲和纯化的牛脑磷脂酰肌醇3激酶（PI3激酶）包含两种主要蛋白质，分子量分别为85 kd和110 kd。氨基酸序列分析和cDNA克隆揭示了两种相关的85 kd蛋白质（p85α和p85β），它们都含有一个SH3结构域和两个SH2结构域（src同源结构域）。当表达时，这些85 kd蛋白质能与酪氨酸磷酸化的受体激酶以及多瘤病毒中T抗原/pp60c-src复合物结合并作为其底物，但缺乏PI3激酶活性。然而，针对p85β产生的抗血清能免疫沉淀PI3激酶活性。含有p85α或p85β以及110 kd蛋白质的活性PI3激酶复合物能与血小板衍生生长因子（PDGF）受体结合，但不能与表皮生长因子（EGF）受体结合。p85α和p85β可能介导PI3激酶与一部分酪氨酸激酶的特异性相互作用。
