Hei Y J, McNeill J H, Sanghera J S, Diamond J, Bryer-Ash M, Pelech S L
Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada.
J Biol Chem. 1993 Jun 25;268(18):13203-13.
Post-insulin receptor signal transduction is mediated by a cascade of seryl/threonyl protein kinases which includes a family of mitogen-activated protein (MAP) kinases, ribosomal protein S6 kinases, and casein kinase-2. Previous studies have characterized these kinases primarily in cultured or isolated cells. We have demonstrated that intravenous injection of insulin into fasted rats significantly stimulated the activities of MAP kinases and S6 kinases in skeletal muscle, independently of the blood glucose levels in these animals. Anion exchange chromatography on Mono Q afforded the resolution of at least five peaks of insulin-stimulated myelin basic protein kinase activity. By immunological criteria, these myelin basic protein kinases included the p42mapk and p44erk1 as well as other potentially novel 44-kDa MAP kinases. Insulin-activated ribosomal S6 kinases were resolved into two major peaks by Mono Q chromatography, the latter of which contained a 100-kDa isoform of p90rsk as revealed by immunoblotting with an anti-rsk-peptide antibody. A 32-kDa S6 kinase in the earlier peak may represent a novel protein kinase in this tissue. Skeletal muscle casein kinase-2 was not significantly stimulated following insulin injection into rats under our experimental conditions. These results indicate that the intact rat can serve as a useful model system to investigate the mechanisms of insulin signal transduction.
胰岛素受体后的信号转导由一系列丝氨酸/苏氨酸蛋白激酶介导，其中包括丝裂原活化蛋白（MAP）激酶家族、核糖体蛋白S6激酶和酪蛋白激酶2。以往的研究主要在培养细胞或分离细胞中对这些激酶进行了表征。我们已经证明，向禁食大鼠静脉注射胰岛素可显著刺激骨骼肌中MAP激酶和S6激酶的活性，而与这些动物的血糖水平无关。在Mono Q上进行阴离子交换层析可分辨出至少五个胰岛素刺激的髓鞘碱性蛋白激酶活性峰。根据免疫学标准，这些髓鞘碱性蛋白激酶包括p42mapk和p44erk1以及其他潜在的新型44 kDa MAP激酶。胰岛素激活的核糖体S6激酶通过Mono Q层析可分辨为两个主要峰，用抗rsk肽抗体进行免疫印迹显示，后一个峰含有100 kDa的p90rsk同工型。较早峰中的一种32 kDa S6激酶可能代表该组织中的一种新型蛋白激酶。在我们的实验条件下，向大鼠注射胰岛素后，骨骼肌酪蛋白激酶2未受到显著刺激。这些结果表明，完整的大鼠可作为研究胰岛素信号转导机制的有用模型系统。
