Neuronal apoptosis-inhibitory protein does not interact with Smac and requires ATP to bind caspase-9
Neuronal apoptosis-inhibitory protein does not interact with Smac and requires ATP to bind caspase-9
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DOI：
10.1074/jbc.m405963200
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发表时间：
2004-09-24
影响因子：
4.8
通讯作者：
MacKenzie, AE
中科院分区：
文献类型：
--
作者：
Davoodi, J;Lin, L;MacKenzie, AE
(n) under bar 欧洲 (a) under bar 凋亡- (i) under bar 抑制 (p) under bar 蛋白 (NAIP) 是 (i) under bar 抑制剂 (ap) under bar 凋亡 (IAP) 蛋白 (也称为 BIRC 蛋白) 的哺乳动物家族的创始成员，并且已被证明在体内和体外均具有抗细胞凋亡作用。 160-kDa NAIP 包含三个不同的区域：在 bar 重复 (BIR) 结构域下的三个 (b) 的氨基末端簇 (b) 在 bar 抑制 (r) 下，在 bar 的寡聚化 (o) 下的中心 (n) 在 bar omain (NOD) 下，以及在 bar 的亮氨酸-(r) 下的羧基末端 (l) 在 bar ich 下 (r) 下条重重复 (LRR) 结构域。 NOD 和 LRR 结构域的存在使得 NAIP 在 IAP 中独一无二，并表明 NAIP 活性的调节方式与该家族其他成员不同。在本报告中，我们研究了 NAIP 各个区域与 caspase-9 和 Smac 的相互作用。羧基末端 LRR 或 NOD-LRR 区域截短的重组 NAIP 与 caspase-9 结合。相比之下，全长蛋白质却没有，这表明存在某种形式的结构自动调节。然而，在 ATP 存在的情况下进行相互作用分析时，观察到野生型全长蛋白与 caspase-9 的关联。此外，NAIP ATP 结合袋的突变允许全长蛋白与 caspase-9 相互作用。因此，我们得出结论，NAIP 与 caspase-9 结合需要 ATP 的结构要求，并且在没有 ATP 的情况下，LRR 结构域负向调节 BIR 结构域的 caspase-9 抑制活性。有趣的是，与 X 染色体连接的凋亡蛋白抑制剂 (XIAP) 相比，NAIP 介导的 caspase-9 抑制不会被含有氨基末端 (I) 的肽所抵消，该肽位于 AP 条下 (b) otif 条下 (IBM) 下的条 inding (m) 下。与此观察结果一致的是 Smac 蛋白未能与 NAIP BIR 结构域相互作用。这些结果表明 NAIP 与其他 IAP 不同，无论是在证明配体依赖性 caspase-9 相互作用方面还是在证明独特的抑制机制方面。
The (n) under bar euronal (a) under bar poptosis- (i) under bar nhibitory (p) under bar rotein (NAIP) is the founding member of the mammalian family of (i) under bar nhibitor of (ap) under bar optosis (IAP) proteins (also known as BIRC proteins) and has been shown to be antiapoptotic both in vivo and in vitro. The 160-kDa NAIP contains three distinct regions: an amino-terminal cluster of three (b) under bar aculoviral (i) under bar nhibitory (r) under bar epeat (BIR) domains, a central (n) under bar ucleotide binding (o) under bar ligomerization (d) under bar omain (NOD), and a carboxyl-terminal (l) under bar eucine-(r) under bar ich (r) under bar epeat (LRR) domain. The presence of the NOD and LRR domains renders NAIP unique among the IAPs and suggests that NAIP activity is regulated in a manner distinct from that of other members of the family. In this report, we examined the interaction of various regions of NAIP with caspase-9 and Smac. Recombinant NAIPs with truncations of the carboxyl-terminal LRR or NOD-LRR regions bound to caspase-9. In contrast, the full-length protein did not, suggesting some form of structural autoregulation. However, the association of the wild type full-length protein with caspase-9 was observed when interaction analysis was performed in the presence of ATP. Furthermore, mutation of the NAIP ATP binding pocket allowed full-length protein to interact with caspase-9. Thus, we conclude that NAIP binds to caspase-9 with a structural requirement for ATP and that in the absence of ATP the LRR domain negatively regulates the caspase-9-inhibiting activity of the BIR domains. Interestingly, and in contrast to the X-chromosome-linked inhibitor of apoptosis protein (XIAP), NAIP-mediated inhibition of caspase-9 was not countered by a peptide containing an amino-terminal (I) under bar AP (b) under bar inding (m) under bar otif (IBM). Consistent with this observation was the failure of Smac protein to interact with the NAIP BIR domains. These results demonstrate that NAIP is distinct from the other IAPs, both in demonstrating a ligand-dependent caspase-9 interaction and in demonstrating a distinct mechanism of inhibition.