Bcl-2 phosphorylation required for anti-apoptosis function
Bcl-2 phosphorylation required for anti-apoptosis function
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DOI：
10.1074/jbc.272.18.11671
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发表时间：
1997-05-02
影响因子：
4.8
通讯作者：
May, WS
中科院分区：
文献类型：
--
作者：
Ito, T;Deng, XM;May, WS
原癌基因Bcl-2作为生长因子依赖性细胞凋亡的抑制因子发挥作用，但受体后信号传导机制尚不清楚。我们最近报道，白细胞介素3（IL-3）和促红细胞生成素，或蛋白激酶C激活剂苔藓抑素-1（Bryo），不仅抑制细胞凋亡，而且刺激Bcl-2的磷酸化（May，W.美国，泰勒，PG，伊藤，T.，Armstrong，D. K.，Qatsha，K.一、和Davidson，N. E.（1994）J.Biol.Chem.269，26865-26870）。为了测试Bcl-2功能是否需要磷酸化，在Bcl-2中的七个推定的蛋白激酶C磷酸化位点产生保守的丝氨酸->丙氨酸突变。结果表明，与野生型Bcl-2相比，S70 A Bcl-2突变体在IL-3或Bryo刺激后不能磷酸化，并且在IL-3剥夺或依托泊苷处理后不能支持延长的细胞存活。相比之下，在不存在IL-3的情况下，可能模拟潜在磷酸电荷的Ser-Glu突变体S70 E比野生型更有效地抑制依托泊苷诱导的细胞凋亡。由于功能丧失S70 A突变体可以与其伴侣蛋白和死亡效应因子Bax异二聚化，这些发现表明Bcl-2：Bax异二聚化是不够的，并且Bcl-2磷酸化是完整的Bcl-2死亡抑制信号传导活性所必需的。
The protooncogene Bcl-2 functions as a suppressor of apoptosis in growth factor-dependent cells, but a postreceptor signaling mechanism is not known. We recently reported that interleukin 3 (IL-3) and erythropoietin, or the protein kinase C activator bryostatin-1 (Bryo), not only suppresses apoptosis but also stimulates the phosphorylation of Bcl-2 (May, W. S., Tyler, P. G., Ito, T., Armstrong, D. K., Qatsha, K. A., and Davidson, N. E. (1994) J. Biol. Chem. 269, 26865-26870). To test whether phosphorylation is required for Bcl-2 function, conservative serine --> alanine mutations were produced at the seven putative protein kinase C phosphorylation sites in Bcl-2. Results indicate that the S70A Bcl-2 mutant fails to be phosphorylated after IL-3 or Bryo stimulation and is unable 60 support prolonged cell survival either upon IL-3 deprivation or etoposide treatment when compared with wild-type Bcl-2. In contrast, a Ser --> Glu mutant, S70E, which may mimic a potential phosphate charge, more potently suppressed the etoposide-induced apoptosis than wild type in the absence of IL-3. Since the loss of function S70A mutant can heterodimerize with its partner protein and death effector Bax, these findings demonstrate that Bcl-2:Bax heterodimerization is not sufficient and Bcl-2 phosphorylation is required for full Bcl-2 death suppressor signaling activity.