Thomsen P, van Deurs B, Norrild B, Kayser L
Department of Medical Anatomy, The Panum Institute, University of Copenhagen, Denmark.
Oncogene. 2000 Dec 7;19(52):6023-32. doi: 10.1038/sj.onc.1204010.
The small hydrophobic E5 protein of Human Papillomavirus type 16 (HPV16) binds to the 16-kDa subunit of the V-H+-ATPase. This binding has been suggested to interfere with acidification of late endocytic structures. We here used video microscopy, ratio imaging and confocal microscopy of living C127 fibroblasts to study the effects of E5. Various endocytic markers including the pH-sensitive probe DM-NERF coupled to dextran, TransFluoSpheres and TRITC-concanavalin A, were applied. In E5-transfected cells, none of these markers colocalized with the membrane permeable probe LysoTracker Red, which accumulates in acidic, late endocytic structures, or with a green fluorescent version of the small GTPase Rab7 labeling late endocytic structures. Importantly, however, late endocytic structures accumulating LysoTracker were still present in the E5-transfected cells. It is therefore concluded that HPV16 E5 perturbs trafficking from early to late endocytic structures rather than acidification.
人乳头瘤病毒16型（HPV16）的小疏水E5蛋白与V-H⁺-ATP酶的16-kDa亚基结合。这种结合被认为会干扰晚期内吞结构的酸化。我们在此使用视频显微镜、比率成像和共聚焦显微镜对活的C127成纤维细胞进行研究，以探究E5的作用。应用了各种内吞标记物，包括与葡聚糖偶联的pH敏感探针DM-NERF、转荧光微球和TRITC-伴刀豆球蛋白A。在转染E5的细胞中，这些标记物均未与膜通透性探针溶酶体示踪剂红色荧光染料共定位，后者积聚在酸性的晚期内吞结构中，也未与标记晚期内吞结构的小GTP酶Rab7的绿色荧光版本共定位。然而，重要的是，积聚溶酶体示踪剂的晚期内吞结构仍存在于转染E5的细胞中。因此得出结论，HPV16 E5干扰从早期到晚期内吞结构的运输，而非酸化过程。
