Alterations in the insulin signaling pathway induced by immortalization and H-ras transformation of brown adipocytes.
Alterations in the insulin signaling pathway induced by immortalization and H-ras transformation of brown adipocytes.
复制标题
棕色脂肪细胞的永生化和 H-ras 转化诱导胰岛素信号通路的改变。
DOI：
10.1210/endo.138.8.5293
复制
发表时间：
1997
期刊：
影响因子：
4.8
通讯作者：
M. Benito
中科院分区：
文献类型：
--
作者：
Á. Valverde;M. Lorenzo;T. Teruel;M. Benito
在胎儿棕色脂肪细胞原代培养物中，胰岛素迅速（5 分钟）诱导胰岛素受体 β 亚基的酪氨酸磷酸化；这种效应在生理浓度 (1 nM) 下达到最大。胰岛素还刺激胰岛素受体底物 1 酪氨酸磷酸化，随后激活磷脂酰肌醇 3-激酶。此外，胰岛素刺激后，Ras.GTP 活性形式增加了 3 倍，Raf-1 激酶活性增加了 6 倍。永生化棕色脂肪细胞系（通过永久猿猴病毒 40 大 T 抗原和 pMEXneo 共转染）在所研究的相同胰岛素浓度范围 (1-100 nM) 中显示出对胰岛素的最大反应性降低。转化的棕色脂肪细胞系（通过永久猿猴病毒 40 大 T 抗原和 pMEXneo H-ras(lys12) 共转染）在 Ras 上游产生胰岛素抵抗，显示胰岛素受体自身磷酸化、胰岛素受体底物 1 酪氨酸磷酸化及其与 1 nM 胰岛素处理后与磷脂酰肌醇 3-激酶的关联受损，尽管胰岛素受体数量和亲和力 (Kd) 保持不变。这种效果的缺乏在用更高浓度的胰岛素治疗后以剂量依赖的方式得到改善。然而，与原代细胞和永生化细胞相比，Ras 下游的事件以胰岛素依赖性方式过度刺激，例如 Ras.GTP 活性形式的形成、Raf-1 激酶和 12-O-十四烷酰佛波醇-13-乙酸酯响应元件-氯霉素转移酶（瞬时转染）活性。来自 H-ras(lys12) 转化的棕色脂肪细胞的小麦胚芽凝集素纯化的受体在基础状态下表现出明显的磷酸化，丝氨酸-苏氨酸磷酸酶预处理可抑制这种磷酸化。此外，碱性磷酸酶预处理恢复了受体响应胰岛素的酪氨酸激酶活性。我们得出结论，H-ras(lys12) 转化的棕色脂肪细胞的胰岛素受体酪氨酸自磷酸化率降低是其基础丝氨酸/苏氨酸磷酸化的结果，导致严重的胰岛素抵抗。
In fetal brown adipocyte primary cultures, insulin rapidly (at 5 min) induced tyrosine phosphorylation of the insulin receptor beta-subunit; this effect was maximal at physiological concentrations (1 nM). Insulin also stimulated insulin receptor substrate-1 tyrosine phosphorylation and subsequently activated phosphatidylinositol 3-kinase. Moreover, a 3-fold increase in the Ras.GTP active form and a 6-fold increase in Raf-1 kinase activity were induced after insulin stimulation. An immortalized brown adipocyte cell line (by permanent simian virus 40 large T antigen and pMEXneo cotransfection) showed a reduced maximal responsiveness to insulin in the same range of insulin concentrations studied (1-100 nM). Transformed brown adipocyte cell line (by permanent simian virus 40 large T antigen and pMEXneo H-ras(lys12) cotransfection) developed insulin resistance upstream from Ras, showing an impairment in the insulin receptor autophosphorylation, and in insulin receptor substrate-1 tyrosine phosphorylation and its association with phosphatidylinositol 3-kinase upon treatment with 1 nM insulin, although insulin receptor number and affinity (Kd) remained unaltered. This lack of effect was ameliorated upon treatment with higher insulin concentrations, in a dose-dependent manner. However, downstream from Ras, events such as formation of the Ras.GTP active form, and Raf-1 kinase and 12-O-tetradecanoylphorbol-13-acetate response element-chloramphenicol transferase (transiently transfected) activities were overstimulated, compared with those in primary and immortalized cells, in an insulin-independent manner. Wheat-germ lectin-purified receptors from H-ras(lys12)-transformed brown adipocytes showed a marked phosphorylation in the basal state, which was suppressed by serine-threonine phosphatase pretreatment. Moreover, alkaline phosphatase pretreatment restored the tyrosine kinase activity of the receptor in response to insulin. We conclude that the decreased tyrosine autophosphorylation rate of the insulin receptor from H-ras(lys12)-transformed brown adipocytes is a consequence of its basal serine/threonine phosphorylation, resulting in severe insulin resistance.
登录
查看更多内容
影响因子：
15.9
作者：
SAAD, MJA;ARAKI, E;KAHN, CR
通讯作者：
KAHN, CR
影响因子：
56.9
作者：
COOK, SJ;MCCORMICK, F
通讯作者：
MCCORMICK, F
佛波酯诱导的胰岛素受体丝氨酸磷酸化降低其酪氨酸激酶活性。
DOI：
--
发表时间：
1988
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Takayama,S;White,MF;Kahn,CR
通讯作者：
Kahn,CR
影响因子：
15.9
作者：
SAAD, MJA;FOLLI, F;KAHN, CR
通讯作者：
KAHN, CR
胰岛素刺激培养脂肪细胞中 c-Jun、c-Fos 和 Fos 相关蛋白的磷酸化。
DOI：
--
发表时间：
1994
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Kim,SJ;Kahn,CR
通讯作者：
Kahn,CR