KSHV vFLIP binds to IKK-γ to activate IKK
KSHV vFLIP binds to IKK-γ to activate IKK
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DOI：
10.1242/jcs.00691
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发表时间：
2003-09-15
影响因子：
4
通讯作者：
Collins, M
中科院分区：
文献类型：
--
作者：
Field, N;Low, W;Collins, M
据报道，当在异源细胞中表达时，卡波济肉瘤相关疱疹病毒（KSHV）的病毒FLIP蛋白（vFLIP）既可以阻断Fas介导的细胞凋亡，又可以通过与IkappaB激酶（IKK）的相互作用激活NF-kappaB激活途径。我们在哺乳动物细胞和细菌中表达IKK γ的片段，并将中心CCR 3/4（氨基酸150-272）鉴定为vFLIP结合区。为了研究在KSHV感染的原发性渗出性淋巴瘤（PEL）细胞系中与vFLIP相互作用的蛋白质，我们免疫沉淀vFLIP，并通过质谱法鉴定了四种相关蛋白：IKK组分IKK α，β和γ，以及伴侣蛋白HSP 90。使用凝胶过滤色谱法，我们证明了在PEL细胞的细胞质中的vFLIP的单一群体与活化的IKK复合物共洗脱和共沉淀。热休克蛋白90的抑制剂格尔德霉素可抑制vFLIP诱导的IKK激酶活性并杀死PEL细胞，表明vFLIP激活IKK有助于PEL细胞存活。
When expressed in heterologous cells, the viral FLIP protein (vFLIP) of Kaposi's-sarcoma-associated herpesvirus (KSHV) has been reported both to block Fas-mediated apoptosis and to activate the NF-kappaB activation pathway by interaction with IkappaB kinase (IKK). In a yeast-two-hybrid screen, we identified IKKgamma as an interacting partner of vFLIP We expressed fragments of IKKgamma in mammalian cells and bacteria, and identified the central CCR3/4 (amino acids 150-272) as the vFLIP binding region. To investigate the proteins interacting with vFLIP in a KSHV-infected primary effusion lymphoma (PEL) cell line, we immunoprecipitated vFLIP and identified four associated proteins by mass spectrometry: IKK components IKKalpha, beta and gamma, and the chaperone, Hsp90. Using gel filtration chromatography, we demonstrated that a single population of vFLIP in the cytoplasm of PEL cells co-eluted and co-precipitated with an activated IKK complex. An inhibitor of Hsp90, geldanamycin, inhibited IKK's kinase activity induced by vFLIP and killed PEL cells, suggesting that vFLIP activation of IKK contributes to PEL cell survival.