由IGF-1R导致BAD磷酸化的细胞凋亡信号通路

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胰岛素样生长因子-1(insulin-like growth factor,IGF-1)是胰岛素样生长因子家族中的一种，通过与IGF-1受体相结合产生生物学效应,是通过内分泌、自分泌和旁分泌的三种途径分泌的低分子 多肽。近些年来,研究发现IGF-1不仅具有胰岛素类似的功能以及介导生长激素的作用，还是多种类型细胞凋亡 的一个重要抑制因子。

IGF-1R, the type 1 receptor for insulin-like growth factor, mediates cell survival and growth in response to its ligands IGF-1 and IGF-2. This tyrosine kinase receptor is widely expressed in many cell types and is a key mediator of growth. Overexpression or activation of IGF-1R may be involved in the proliferation of transformed cells, making inhibition of IGF-1R signaling a strategy for the development of cancer drugs. IGF-1R activates three signaling pathways that converge to phosphorylate BAD protein and block apoptosis. The first pathway activated by IGF-1R stimulates PI3-kinase and the AKT pathway to phosphorylate BAD and block apoptosis. A second pathway activated by IGF-1R involves ras mediated activation of the map kinase pathway to block apoptosis. A third pathway involves interaction of raf with mitochondria in response to IGF-1R activation. The convergence of these pathways to block apoptosis may enhance the IGF-1R response.