c-Cbl-Mediated Selective Virus-Receptor Translocations into Lipid Rafts Regulate Productive Kaposi's Sarcoma-Associated Herpesvirus Infection in Endothelial Cells
c-Cbl-Mediated Selective Virus-Receptor Translocations into Lipid Rafts Regulate Productive Kaposi's Sarcoma-Associated Herpesvirus Infection in Endothelial Cells
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DOI：
10.1128/jvi.05953-11
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发表时间：
2011-12-01
影响因子：
5.4
通讯作者：
Chandran, Bala
中科院分区：
文献类型：
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作者：
Chakraborty, Sayan;ValiyaVeettil, Mohanan;Chandran, Bala
在靶细胞进入和感染过程中，许多包膜和无包膜病毒利用细胞表面受体易位进入脂筏（LR）。然而，这种易位背后的机制尚不清楚。卡波西肉瘤相关疱疹病毒（KSHV）与人微血管真皮内皮（HMVEC-d）细胞表面硫酸乙酰肝素（HS）、整合素α 3 β 1、α V β 3和α V β 5以及氨基酸转运蛋白x-CT蛋白相互作用，并通过c-Cbl-泡介导的巨胞饮作用进入（Veettil et al. J. Virol. 82：12126-12144，2008; Veettil等人，PLoS病理学6：e1001238，2010）。我们已经证实，在感染的早期（感染后1分钟），c-Cbl诱导KSHV选择性易位进入LR，沿着的是α 3 β 1、α V β 3和x-CT受体，而不是α V β 5。活化的c-Cbl定位于巨胞饮细胞大泡的交界处。LR易位的α 3 β 1和α V β 3被单泛素化，导致生产性巨胞饮细胞进入，而非LR相关的α V β 5被多泛素化，导致靶向溶酶体的网格蛋白进入。c-Gbl敲除阻止了巨胞饮和受体易位，并将KSHV转移到网格蛋白-溶酶体非感染途径。用M β CD破坏LR也观察到类似的结果。这些研究提供了第一个证据，c-Cbl调节选择性KSHV-α 3 β 1，-α V β 3和-x-CT受体易位到LR和受体的差异泛素化，这是巨胞饮细胞进入途径和KSHV的生产性感染的关键决定因素。我们的研究表明，针对c-Cbl和LRs的干预措施是阻断KSHV感染内皮细胞的潜在途径。
During target cell entry and infection, many enveloped and nonenveloped viruses utilize cell surface receptors that translocate into lipid rafts (LRs). However, the mechanism behind this translocation is not known. Kaposi's sarcoma-associated herpesvirus (KSHV) interacts with the human microvascular dermal endothelial (HMVEC-d) cell surface heparan sulfate (HS), integrins alpha 3 beta 1, alpha V beta 3, and alpha V beta 5, and the amino acid transporter x-CT protein and enters via c-Cbl-bleb-mediated macropinocytosis (Veettil et al., J. Virol. 82: 12126-12144, 2008; Veettil et al., PLoS Pathog. 6:e1001238, 2010). Here we have demonstrated that very early during infection (1 min postinfection), c-Cbl induced the selective translocation of KSHV into the LR along with the alpha 3 beta 1, alpha V beta 3, and x-CT receptors but not alpha V beta 5. Activated c-Cbl localized with LRs at the junctional base of macropinocytic blebs. LR-translocated alpha 3 beta 1 and alpha V beta 3 were monoubiquitinated, leading to productive macropinocytic entry, whereas non-LR-associated alpha V beta 5 was polyubiquitinated, leading to clathrin entry that was targeted to lysosomes. c-Cbl knockdown blocked the macropinocytosis and receptor translocation and diverted KSHV to a clathrin-lysosomal noninfectious pathway. Similar results were also seen by LR disruption with M beta CD. These studies provide the first evidence that c-Cbl regulates selective KSHV-alpha 3 beta 1, -alpha V beta 3, and -x-CT receptor translocations into the LRs and differential ubiquitination of receptors which are critical determinants of the macropinocytic entry route and productive infection of KSHV. Our studies suggest that interventions targeting c-Cbl and LRs are potential avenues to block KSHV infection of endothelial cells.