Binding of FADD and caspase-8 to molluscum contagiosum virus MC159 Ni-FLIP is not sufficient for its antiapoptotic function
Binding of FADD and caspase-8 to molluscum contagiosum virus MC159 Ni-FLIP is not sufficient for its antiapoptotic function
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DOI：
10.1128/jvi.76.2.697-706.2002
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发表时间：
2002-01-01
影响因子：
5.4
通讯作者：
Cohen, JI
中科院分区：
文献类型：
--
作者：
Garvey, TL;Bertin, J;Cohen, JI
传染性软疣病毒（MCV）是人类痘病毒家族的成员，编码MC 159蛋白，其抑制Fas、肿瘤坏死因子（TNF）和TNF相关的凋亡诱导配体（TRAIL）诱导的细胞凋亡。我们使用定点诱变改变带电或疏水氨基酸残基丙氨酸，以确定MC 159的区域，这是保护细胞凋亡和蛋白质-蛋白质相互作用的关键。令人惊讶的是，虽然MC 159被认为通过与Fas相关死亡结构域（FADD）或半胱天冬酶-8结合来阻断细胞凋亡，但失去细胞凋亡阻断活性的几种突变体仍然与FADD和半胱天冬酶-8结合。在MC 159内的两个死亡效应结构域（DED）的预测疏水补丁I和α 2区域中的突变导致结合FADD或半胱天冬酶-8和阻断细胞凋亡的能力的丧失。位于任一DED的α 6区域中的RXDL基序中的氨基酸取代导致丧失对Fas、TNF和TRAIL诱导的细胞凋亡的保护，并消除了MC 159阻断死亡效应丝形成的能力。因此，MC 159 DED的三个区域（疏水补丁1、α 2和α 6）中的带电或疏水氨基酸对于蛋白质与细胞蛋白质相互作用和阻断细胞凋亡的能力是至关重要的。
Molluscum contagiosum virus (MCV), a member of the human poxvirus family, encodes the MC159 protein that inhibits Fas-, tumor necrosis factor (TNF)-, and TNF-related apoptosis-inducing ligant (TRAIL)-induced apoptosis. We used site-directed mutagenesis to change charged or hydrophobic amino acid residues to alanines to identify regions of MC159 that are critical for protection from apoptosis and for protein-protein interactions. Surprisingly, while MC159: is thought to block apoptosis, by binding to Fas-associated death domain (FADD) or caspase-8, several mutants that lost apoptosis blocking activity still bound to both FADD and caspase-8. Mutations in the predicted hydrophobic patch I and alpha2 regions of both death effector domains (DEDs) within MC159 resulted in loss of the ability to bind to,FADD or caspase-8 and to block apoptosis. Amino acid substitutions in the RXDL motif located in the alpha6 region of either DED resulted in loss of protection from apoptosis induced by Fas, TNF, and TRAIL and abolished the ability of MC159 to block death effector filament formation. Thus, charged or hydrophobic amino acids in three regions of the MC159 DEDs (hydrophobic patch 1, alpha2, and alpha6) are critical for the protein's ability to interact with cellular proteins and to block apoptosis.