Linkage of the BH4 domain of Bcl-2 and the nuclear factor κB signaling pathway for suppression of apoptosis
Linkage of the BH4 domain of Bcl-2 and the nuclear factor κB signaling pathway for suppression of apoptosis
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DOI：
10.1074/jbc.274.41.29505
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发表时间：
1999-10-08
影响因子：
4.8
通讯作者：
Kirshenbaum, LA
中科院分区：
文献类型：
--
作者：
de Moissac, D;Zheng, H;Kirshenbaum, LA
核因子（NF）κ B是一种广泛表达的转录因子，其功能受细胞质抑制蛋白I κ B α调节。我们先前已经表明I κ B α活性在表达Bcl-2的心室肌细胞中减少（de Moissac，D.，Mustapha，S.，Greenberg，A. H、和Kirshenbaum，L. A.（1998）J.Biol.Chem.273，23946-23951）。鉴于越来越多的证据表明Bcl-2保守的N-末端BH 4结构域在抑制细胞凋亡中起关键作用，我们确定该区域是否解释了Bcl-2对I κ B α活性的潜在影响。与载体转染的对照细胞相比，用全长Bcl-2转染人胚胎293细胞导致I κ B α活性显著降低1.9倍（p < 0.006），同时DNA结合增加，NF κ B依赖性基因转录增加3.4倍（p < 0.022）。相比之下，在BH 4结构域缺失突变体（残基10-30）或BH 4结构域点取代突变体I14 G、V15 G、Y18 G、K22 G和L23 G中均未检测到I κ B α活性的显著变化（p = 2.77）。然而，注意到BH 4突变体I19 G的I κ B α活性小的0.60倍降低（p < 0.04），表明该残基对于I κ B α调节可能不是关键的。此外，腺病毒介导的I κ B α突变体的递送以防止NF κ B活化损害了Bcl-2抑制由TNF α加放线菌酮引起的心室肌细胞凋亡的能力，这些数据提供了Bcl-2通过一种机制调节I κ B α的第一个证据，该机制需要连接Bcl-2的保守BH 4结构域。2的NF κ B B信号通路抑制细胞凋亡。
Nuclear factor (NF) kappa B is a ubiquitously expressed transcription factor whose function is regulated by the cytoplasmic inhibitor protein, I kappa B alpha. We have previously shown that I kappa B alpha activity is diminished in ventricular myocytes expressing Bcl-2, (de Moissac, D., Mustapha, S., Greenberg, A. H., and Kirshenbaum, L. A. (1998) J. Biol. Chem. 273, 23946-23951). In view of the growing evidence that the conserved N-terminal BH4 domain of Bcl-2 plays a critical role in suppressing apoptosis, we ascertained whether this region accounts for the underlying effects of Bcl-2 on I kappa B alpha activity. Transfection of human embryonic 293 cells with full length Bcl-2 resulted in a significant 1.9-fold reduction in I kappa B alpha activity (p < 0.006) with a concomitant increase in DNA binding and 3.4-fold increase in NF kappa B-dependent gene transcription (p < 0.022) compared with vector transfected control cells. In contrast, no significant change in I kappa B alpha activity was detected with either a BH4 domain deletion mutant (residues 10-30) or BH4 domain point substitution mutants, I14G, V15G, Y18G, K22G, and L23G (p = 2.77). However, a small 0.60-fold decrease (p < 0.04) in I kappa B alpha activity was noted with the BH4 mutant I19G, suggesting that this residue may not be critical for I kappa B alpha regulation. Furthermore, adenovirus-mediated delivery of an I kappa B alpha mutant to prevent NF kappa B activation impaired the ability of Bcl-2 to suppress apoptosis provoked by TNF alpha plus cycloheximide in ventricular myocytes, The data provide the first evidence for the regulation of I kappa B alpha by Bcl-2 through a mechanism that requires the conserved BH4 domain that links Bcl-2 to the NF kappa B signaling pathway for suppression of apoptosis.