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Abstract：
Oncogenic HPV E6 proteins have a PDZ-binding motif (PBM) which plays important roles in both the viral life cycle and tumor development. The PBM confers interaction with a large number of different PDZ domain-containing substrates, one of which is Sorting Nexin 27. This protein is part of the retromer complex and plays an important role in endocytic sorting pathways. It has been shown that at least two SNX27 interacting partners, GLUT1 and TANC2, are aberrantly trafficked due to the E6 PBM-dependent interaction with SNX27. To investigate further which other components of the endocytic trafficking pathway might be affected by the SNX27-HPV E6 interaction, we analyzed the SNX27 proteome interaction profile in a previously described HeLa cell line expressing GFP-SNX27, both in the presence and absence of the HPV-18 E6 oncoprotein. In this study, we identify a novel interacting partner of SNX27, secreted glycoprotein EMILIN2, whose release is blocked by HPV18 E6 in a PBM-dependent manner. Mechanistically, E6 can block EMILIN2 interaction with the WNT1 ligand, thereby enhancing WNT1 signaling and promoting cell proliferation.
OBJECTIVE: This study demonstrates that HPV E6 blocks EMILIN2 inhibition of WNT1 signaling, thereby enhancing cell proliferation in HPV-positive tumor cells. This involves a novel mechanism whereby the E6 PBM actually contributes toward enhancing the interaction between SNX27 and EMILIN2, suggesting that the mode of recognition of SNX27 by E6 and EMILIN2 is different. This is the first example of the E6 PBM altering a PDZ domain-containing protein to enhance potential substrate recognition.
OBJECTIVE: This study demonstrates that HPV E6 blocks EMILIN2 inhibition of WNT1 signaling, thereby enhancing cell proliferation in HPV-positive tumor cells. This involves a novel mechanism whereby the E6 PBM actually contributes toward enhancing the interaction between SNX27 and EMILIN2, suggesting that the mode of recognition of SNX27 by E6 and EMILIN2 is different. This is the first example of the E6 PBM altering a PDZ domain-containing protein to enhance potential substrate recognition.
摘要：
致癌HPVE6蛋白具有PDZ结合基序（PBM），在病毒生命周期和肿瘤发展中起重要作用。PBM赋予与大量不同的含PDZ结构域的底物相互作用，其中之一是排序Nexin27。该蛋白质是逆转录复合物的一部分，在胞吞分选途径中起重要作用。已经表明，至少有两个SNX27交互伙伴，由于E6PBM与SNX27的依赖相互作用，GLUT1和TANC2被异常贩运。为了进一步研究内吞运输途径的其他成分可能受到SNX27-HPVE6相互作用的影响，我们分析了在存在和不存在HPV-18E6癌蛋白的情况下，先前描述的表达GFP-SNX27的HeLa细胞系中的SNX27蛋白质组相互作用谱。在这项研究中,我们确定了SNX27的一个新的相互作用伴侣,分泌的糖蛋白EMILIN2,其释放以PBM依赖性方式被HPV18E6阻断.机械上,E6可以阻断EMILIN2与WNT1配体的相互作用，从而增强WNT1信号传导并促进细胞增殖。
目的：本研究表明HPVE6阻断了EMILIN2对WNT1信号的抑制，从而增强HPV阳性肿瘤细胞中的细胞增殖。这涉及一种新机制，其中E6PBM实际上有助于增强SNX27和EMILIN2之间的相互作用，这表明E6和EMILIN2识别SNX27的方式是不同的。这是E6PBM改变含PDZ结构域的蛋白质以增强潜在底物识别的第一个实例。
目的：本研究表明HPVE6阻断了EMILIN2对WNT1信号的抑制，从而增强HPV阳性肿瘤细胞中的细胞增殖。这涉及一种新机制，其中E6PBM实际上有助于增强SNX27和EMILIN2之间的相互作用，这表明E6和EMILIN2识别SNX27的方式是不同的。这是E6PBM改变含PDZ结构域的蛋白质以增强潜在底物识别的第一个实例。
