PKN binds and phosphorylates human papillomavirus E6 oncoprotein
PKN binds and phosphorylates human papillomavirus E6 oncoprotein
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DOI：
10.1074/jbc.275.20.14824
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发表时间：
2000-05-19
影响因子：
4.8
通讯作者：
Band, V
中科院分区：
文献类型：
--
作者：
Gao, QS;Kumar, A;Band, V
高危人乳头瘤病毒（hpv）与宫颈癌和其他生殖器肿瘤有关。先前的研究已经确定了两种病毒癌蛋白E6和E7，它们在大多数hpv相关癌中表达。高危HPV E6蛋白永生化人乳腺上皮细胞的能力为研究eg诱导的癌性转化机制提供了一个单基因模型。近年来，我们发现除了egg诱导的p53肿瘤抑制蛋白降解外，乳腺上皮细胞的永生化还需要E6的其他靶点。利用酵母双杂交系统，我们发现了HPV16 E6与蛋白激酶PKN的一种新的相互作用。一种脂肪酸和Rho小G蛋白激活的丝氨酸/苏氨酸激酶，催化结构域与蛋白激酶c高度同源。我们在体外和体内293T细胞中证实了小麦胚芽裂解液中高风险的HPV E6蛋白与PKN的直接结合。重要的是，高风险hpv而非低风险hpv的E6蛋白能够结合PKN，此外，所有永生化能力和许多永生化能力不足的E6突变体都能结合PKN。这些数据表明，与PKN的结合可能是正常乳腺上皮细胞永生所必需的，但不是充分的。最后，我们发现PKN磷酸化E6，首次证明HPV E6是一种磷酸化蛋白。我们的发现表明HPV E6介导的肿瘤发生与一个众所周知的磷酸化级联调节之间存在新的联系。
The high risk human papillomaviruses (HPVs) are associated with carcinomas of cervix and other genital tumors. Previous studies have identified two viral oncoproteins E6 and E7, which are expressed in the majority of HPV-associated carcinomas. The ability of high risk HPV E6 protein to immortalize human mammary epithelial cells has provided a single gene model to study the mechanisms of EG-induced oncogenic transformation. In recent years, it has become clear that in addition to EG-induced degradation of p53 tumor suppressor protein, other targets of E6 are required for mammary epithelial cells immortalization, Using the yeast two-hybrid system, we have identified a novel interaction of HPV16 E6 with protein kinase PKN, a fatty acid- and Rho small G protein-activated serine/threonine kinase with a catalytic domain highly homologous to protein kinase C. We demonstrate direct binding of high risk HPV E6 proteins to PKN in wheat-germ lysate in vitro and in 293T cells in vivo. Importantly, E6 proteins of high risk HPVs but not low risk HPVs were able to bind PKN, Furthermore, all the immortalization-competent and many immortalization-non-competent E6 mutants bind PKN. These data suggest that binding to PKN may be required but not sufficient for immortalizing normal mammary epithelial cells, Finally, we show that PKN phosphorylates E6, demonstrating for the first time that HPV E6 is a phosphoprotein, Our finding suggests a novel link between HPV E6 mediated oncogenesis and regulation of a well known phosphorylation cascade.