The growth-promoting activity of the Bad protein in chicken embryo fibroblasts requires binding to protein 14-3-3
The growth-promoting activity of the Bad protein in chicken embryo fibroblasts requires binding to protein 14-3-3
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DOI：
10.1038/sj.onc.1204662
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发表时间：
2001-08-23
期刊：
影响因子：
8
通讯作者：
Vogt, PK
中科院分区：
文献类型：
--
作者：
Maslyar, DJ;Aoki, M;Vogt, PK
Bad蛋白的磷酸化是生存因子预防细胞凋亡的一个关键调节事件。磷酸化的Bad与胞质14 - 3 - 3蛋白结合，并从线粒体膜的凋亡机制中被隔离出来。为了研究Bad在原代培养细胞的生长和凋亡中的作用，我们制备了鸡胚成纤维细胞（CEF）的稳定Bad转染细胞。正如预期的那样，Bad转染细胞的血清饥饿促进了细胞凋亡。然而，在高血清浓度培养基中培养的Bad转染的CEF能够进行非贴壁依赖性生长，并且比空载体转染的对照CEF生长到更高的饱和密度。高稀释度的表达Bad的感染性逆转录病毒载体RCAS导致了多层细胞灶的形成。Bad的促生长作用依赖于丝氨酸136磷酸化位点，并且与Bad和14 - 3 - 3的结合直接相关。这些结果表明，磷酸化的Bad促进细胞生长，并且在致癌转化中可能有助于细胞的肿瘤表型。
Phosphorylation of the Bad protein is a key regulatory event in the prevention of apoptosis by survival factors. Phosphorylated Bad binds to the cytosolic 14-3-3 protein and is sequestered from the apoptotic machinery of the mitochondrial membrane. To examine the role of Bad in cell growth and apoptosis in primary cultures, we produced stable Bad transfectants of chicken embryo fibroblasts (CEF). As expected, serum starvation of Bad transfectants promoted apoptosis. However, Bad-transfected CEF maintained in media with a high serum concentration were capable of anchorage-independent growth and grew to a higher saturation density than control CEF transfected with the empty vector. High dilutions of the infectious retroviral vector RCAS expressing Bad led to the formation of multilayered cell foci. The growth-promoting effects of Bad were dependent on the serine 136 phosphorylation site and correlated directly with binding of Bad to 14-3-3. These results suggest that phosphorylated Bad promotes cell growth and in oncogenic transformation may contribute to the neoplastic phenotype of the cell.