Akt-dependent antiapoptotic action of insulin is sensitive to farnesyltransferase inhibitor
Akt-dependent antiapoptotic action of insulin is sensitive to farnesyltransferase inhibitor
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DOI：
10.1021/bi000995y
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发表时间：
2000-10-17
期刊：
影响因子：
2.9
通讯作者：
Bernier, M
中科院分区：
文献类型：
--
作者：
Park, D;Pandey, SK;Bernier, M
表达人胰岛素受体（IR）的CHO细胞用于评价强效法尼基转移酶抑制剂manumycin对胰岛素抗凋亡功能的影响。用manumycin处理细胞阻断了胰岛素抑制促凋亡caspase-3活性的能力，这导致两种核靶蛋白的时间依赖性蛋白水解裂解。Raf-1/MEK/ERK级联和丝氨酸/苏氨酸蛋白激酶Akt是可响应于胰岛素而被激活的两种存活途径。我们检验了法尼基化Ras的抑制与manumycin诱导的细胞凋亡有因果关系的假设，并表明对manumycin的反应被发现与K-Ras功能无关，因为在用manumycin处理后，膜缔合和内源性K-Ras蛋白在GTP负载和ERK激活方面的激活没有减弱。此外，通过在CHO-IR细胞中表达反式显性抑制性mSOS 1突变体来阻断p21 Ras/Raf-1/MEK/ERK级联反应，使细胞对胰岛素的抗凋亡作用保持敏感。用manumycin处理4 h可阻断AM的胰岛素依赖性激活（P < 0.01），这种动力学太快而不能用Ras抑制来解释。这项研究表明，Manumycin的短暂法尼基化蛋白质的消耗抑制胰岛素的抗凋亡作用，至少部分是通过破坏Akt的激活，但不是K-Ras/Raf-1/ERK依赖性级联反应。
CHO cells expressing the human insulin receptors (IR) were used to evaluate the effect of the potent farnesyltransferase inhibitor, manumycin, on insulin antiapoptotic function. Cell treatment with manumycin blocked insulin's ability to suppress pro-apoptotic caspase-3 activity which led to time-dependent proteolytic cleavage of two nuclear target proteins. The Raf-1/MEK/ERK cascade and I he serine/threonine protein kinase Akt are two survival pathways that may be activated in response to insulin. We tested the hypothesis that inhibition of farnesylated Ras was causally related to manumycin-induced apoptosis and showed that the response to manumycin was found to be independent of K-Ras function because membrane association and activation of endogenous K-Ras proteins in terms of GTP loading and ERK activation were unabated following treatment with manumycin. Moreover, blocking p21Ras/Raf-1/MEK/ERK cascade by the expression of a transdominant inhibitory mSOS1 mutant in CHO-IR cells kept cells sensitive to the antiapoptotic action of insulin. Insulin-dependent activation of AM was blocked by 4 h treatment with manumycin (P < 0.01), a kinetic too rapid to be explained by Ras inhibition. This study suggests that the depletion of short-lived farnesylated proteins by manumycin suppresses the antiapoptotic action of insulin at least in part by disrupting Akt activation but not that of the K-Ras/Raf-1/ERK-dependent cascade.