Multiple Heparan Sulfate Binding Site Engagements Are Required for the Infectious Entry of Human Papillomavirus Type 16
Multiple Heparan Sulfate Binding Site Engagements Are Required for the Infectious Entry of Human Papillomavirus Type 16
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DOI：
10.1128/jvi.01721-13
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发表时间：
2013-11-01
影响因子：
5.4
通讯作者：
Sapp, Martin
中科院分区：
文献类型：
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作者：
Richards, Kathleen F.;Bienkowska-Haba, Malgorzata;Sapp, Martin
人乳头瘤病毒（HPV）的进入伴随着多种受体诱导的构象变化（CC），影响主要和次要衣壳蛋白L1和L2。硫酸乙酰肝素（HS）与L1的相互作用是HPV 16成功进入的关键。最近，HPV16与肝素的共结晶揭示了四个不同的结合位点。在这里，我们的特点突变型HPV 16描绘的作用，在感染性内化与HS结合位点的参与。介导初级结合的位点1（Lys278、Lys361）足以触发L2 CC，从而暴露氨基末端。位点2（Lys54、Lys356）和位点3（Asn57、Lys59、Lys442、Lys443）在初级附着后接合，并且是感染进入所需的。位点2突变体颗粒被有效地内化，但不能在细胞表面上经历L1 CC，随后在内吞隔室中脱包被。在最初附着到细胞后，位点3突变体经历L1和L2 CC，然后在细胞外基质（ECM）上积累。我们得出结论，在位点1和位点2相互作用后诱导CC导致细胞表面上的主要HS结合位点的亲和力降低，这允许与位点3接合。两者合计，我们的研究结果表明，HS结合位点接合诱导CC，准备病毒的下游事件，如暴露的二级结合位点，CC，转移到摄取受体，和脱壳。
Human papillomavirus (HPV) entry is accompanied by multiple receptor-induced conformational changes (CCs) affecting both the major and minor capsid proteins, L1 and L2. Interaction of heparan sulfate (HS) with L1 is essential for successful HPV16 entry. Recently, cocrystallization of HPV16 with heparin revealed four distinct binding sites. Here we characterize mutant HPV16 to delineate the role of engagement with HS binding sites during infectious internalization. Site 1 (Lys278, Lys361), which mediates primary binding, is sufficient to trigger an L2 CC, exposing the amino terminus. Site 2 (Lys54, Lys356) and site 3 (Asn57, Lys59, Lys442, Lys443) are engaged following primary attachment and are required for infectious entry. Site 2 mutant particles are efficiently internalized but fail to undergo an L1 CC on the cell surface and subsequent uncoating in the endocytic compartment. After initial attachment to the cell, site 3 mutants undergo L1 and L2 CCs and then accumulate on the extracellular matrix (ECM). We conclude that the induction of CCs following site 1 and site 2 interactions results in reduced affinity for the primary HS binding site(s) on the cell surface, which allows engagement with site 3. Taken together, our findings suggest that HS binding site engagement induces CCs that prepare the virus for downstream events, such as the exposure of secondary binding sites, CCs, transfer to the uptake receptor, and uncoating.