Kanai F, Ito K, Todaka M, Hayashi H, Kamohara S, Ishii K, Okada T, Hazeki O, Ui M, Ebina Y
Department of Enzyme Genetics, University of Tokushima, Japan.
Biochem Biophys Res Commun. 1993 Sep 15;195(2):762-8. doi: 10.1006/bbrc.1993.2111.
We examined the role of 185-kDa insulin receptor substrate-1 (IRS-1) and phosphatidylinositol 3-kinase (PI3-kinase) in the signaling pathway of insulin-stimulated GLUT4 translocation. We had already developed a novel cell line to detect GLUT4 on the cell surface, directly and sensitively (Kanai, F., Nishioka, Y., Hayashi, H., Kamohara, S., Todaka, M., and Ebina, Y. (1993) J. Biol. Chem. 268, 14523-14526). We stably expressed a mutant insulin receptor in which Tyr972 was replaced with phenylalanine. Insulin-stimulated tyrosyl phosphorylation of IRS-1 and GLUT4 translocation were decreased in cells expressing the mutant receptor, as compared to findings in cells expressing the normal receptor. Wortmannin, an inhibitor of PI3-kinase, inhibits the insulin-stimulated PI3-kinase activity and GLUT4 translocation at 50 nM, but not the NaF-stimulated GLUT4 translocation. These results suggest that the tyrosine phosphorylation of IRS-1 and activation of PI3-kinase may be involved in the signaling pathway of the insulin-stimulated GLUT4 translocation.
我们研究了185-kDa胰岛素受体底物-1（IRS-1）和磷脂酰肌醇3-激酶（PI3-激酶）在胰岛素刺激的GLUT4转位信号通路中的作用。我们已经建立了一种新型细胞系，可直接且灵敏地检测细胞表面的GLUT4（Kanai, F., Nishioka, Y., Hayashi, H., Kamohara, S., Todaka, M., and Ebina, Y. (1993) J. Biol. Chem. 268, 14523 - 14526）。我们稳定表达了一种酪氨酸972被苯丙氨酸取代的突变胰岛素受体。与表达正常受体的细胞相比，在表达突变受体的细胞中，胰岛素刺激的IRS-1酪氨酸磷酸化和GLUT4转位减少。PI3-激酶抑制剂渥曼青霉素在50 nM时可抑制胰岛素刺激的PI3-激酶活性和GLUT4转位，但不抑制氟化钠刺激的GLUT4转位。这些结果表明，IRS-1的酪氨酸磷酸化和PI3-激酶的激活可能参与胰岛素刺激的GLUT4转位信号通路。
