D-3 phosphoinositide metabolism in cells treated with platelet-derived growth factor.
D-3 phosphoinositide metabolism in cells treated with platelet-derived growth factor.
复制标题
用血小板衍生生长因子处理的细胞中 D-3 磷酸肌醇的代谢。
DOI：
10.1042/bj3190851
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Ulug,ET
中科院分区：
文献类型：
--
作者：
Whiteford,CC;Best,C;Kazlauskas,A;Ulug,ET
尽管在分子水平上对磷酸肌苷3-羟基激酶（PI 3-激酶）进行了广泛的分析，但对这些酶的产物发挥其预期的第二信使功能的机制知之甚少。本研究探讨了缺乏血小板衍生生长因子(PDGF) α-受体的小鼠Ph-N2成纤维细胞中D-3磷酸肌苷的代谢。用BB PDGF而不是AA PDGF处理这些培养物，可以在体外测量PI 3-激酶活性的瞬时激活。用BB PDGF处理myo-[3H]肌醇标记的Ph-N2细胞可快速诱导PtdIns(3,4) p2和PtdIns(3,4,5) p3，并在较小程度上诱导PtdIns3P。PtdIns(3,4,5) p3的出现先于PtdIns(3,4) p2和ptdins3p2的出现，这表明PtdIns(4,5) p2是完整细胞中激动剂刺激的PI - 3激酶的首选底物。用真菌代谢物wortmannin处理静息和pdgf刺激的细胞，对所有D-3磷酸肌苷的水平产生明显的选择性影响。用这种PI 3-激酶抑制剂进行的动力学研究表明，在pdgf处理的细胞中，至少存在两种独立的D-3磷酸肌苷生物合成途径。
Despite extensive analysis of phosphoinositide 3-hydroxykinases (PI 3-kinases) at the molecular level, comparatively little is known about the mechanisms by which products of these enzymes exert their expected second-messenger functions. This study examines the metabolism of D-3 phosphoinositides in mouse Ph-N2 fibroblasts lacking the platelet-derived growth factor (PDGF) α-receptor. Treatment of these cultures with BB PDGF, but not AA PDGF, resulted in transient activation of PI 3-kinase activity measuredin vitro. Treatment ofmyo-[3H]inositol-labelled Ph-N2 cells with BB PDGF resulted in the rapid induction of PtdIns(3,4)P2and PtdIns(3,4,5)P3and, to a smaller extent, PtdIns3P. The appearance of PtdIns(3,4,5)P3preceded that of PtdIns(3,4)P2and PtdIns3Pafter the addition of PDGF, suggesting that PtdIns(4,5)P2is the preferred substrate of the agonist-stimulated PI 3-kinase in intact cells. Treatment of both resting and PDGF-stimulated cells with the fungal metabolite wortmannin resulted in pronounced, selective effects on the levels of all D-3 phosphoinositides. Kinetic studies with this PI 3-kinase inhibitor revealed the presence of at least two independent routes for the biosynthesis of D-3 phosphoinositides in PDGF-treated cells.