Waters S B, Yamauchi K, Pessin J E
Department of Physiology and Biophysics, University of Iowa, Iowa City 52242.
J Biol Chem. 1993 Oct 25;268(30):22231-4.
To examine the role of the insulin receptor substrate-1 (IRS-1) in mediating insulin biological responsiveness, we generated Chinese hamster ovary cell lines expressing antisense IRS-1 RNA. These cells displayed morphological alterations as well as markedly reduced growth rates compared to the parental cells. Furthermore, the antisense IRS-1 cell lines had decreased insulin-stimulated IRS-1 tyrosine phosphorylation, reduced phosphatidylinositol 3-kinase activation, and decreased thymidine incorporation relative to the parental cell line. Insulin-dependent transcriptional regulation of a serum response element/luciferase reporter construct (SRE-Luc) was also reduced in the antisense IRS-1-expressing cell lines. However, co-transfection with a plasmid directing the expression of rat IRS-1 fully restored insulin-stimulated SRE-Luc activity in the IRS-1 antisense cell lines. Thus, the inhibition in insulin signaling was a specific effect of decreased IRS-1 tyrosine phosphorylation. Taken together, these data demonstrate that insulin regulation of mitogenic signaling requires the functional expression of IRS-1 and documents its central importance in the insulin intracellular signaling pathway.
为了研究胰岛素受体底物-1（IRS-1）在介导胰岛素生物学反应性中的作用，我们构建了表达反义IRS-1 RNA的中国仓鼠卵巢细胞系。与亲本细胞相比，这些细胞表现出形态学改变以及生长速率显著降低。此外，与亲本细胞系相比，反义IRS-1细胞系中胰岛素刺激的IRS-1酪氨酸磷酸化减少，磷脂酰肌醇3-激酶激活降低，胸苷掺入减少。在表达反义IRS-1的细胞系中，血清反应元件/荧光素酶报告基因构建体（SRE-Luc）的胰岛素依赖性转录调节也降低。然而，用指导大鼠IRS-1表达的质粒共转染可完全恢复IRS-1反义细胞系中胰岛素刺激的SRE-Luc活性。因此，胰岛素信号传导的抑制是IRS-1酪氨酸磷酸化减少的特异性效应。综上所述，这些数据表明胰岛素对有丝分裂信号的调节需要IRS-1的功能性表达，并证明了其在胰岛素细胞内信号通路中的核心重要性。
