Integrin αVβ3 binds to the RGD motif of glycoprotein B of Kaposi's sarcoma-associated herpesvirus and functions as an RGD-dependent entry receptor
Integrin αVβ3 binds to the RGD motif of glycoprotein B of Kaposi's sarcoma-associated herpesvirus and functions as an RGD-dependent entry receptor
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DOI：
10.1128/jvi.01673-07
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发表时间：
2008-02-01
影响因子：
5.4
通讯作者：
Rose, Timothy M.
中科院分区：
文献类型：
--
作者：
Garrigues, H. Jacques;Rubinchikova, Yelena E.;Rose, Timothy M.
卡波西肉瘤相关疱疹病毒 (KSHV) 包膜相关糖蛋白 B (gB) 参与 KSHV 感染期间与宿主细胞结合的初始步骤。 gB 含有一个 RGD 基序，据报道在病毒进入期间可结合整合素 α(3)β(1)。尽管α(3)β(1)的配体特异性一直存在争议，但目前的文献表明α(3)β(1)配体识别与RGD无关。我们将 alpha(3)beta(1) 与 RGD 结合整合素 alpha(V)beta(3) 进行比较，以结合包膜相关的 gB 和 gB(RGD) 肽。粘附测定表明，过表达α(V)β(3)的β(3)-CHO细胞特异性结合gB(RGD)，而过表达α(3)β(1)的α(3)-CHO细胞则不然。 α(V)β(3) 功能阻断抗体抑制 HT1080 纤维肉瘤细胞与 gB(RGD) 的粘附，而 α(3)β(1) 抗体则不然。使用亲和纯化的整合素和共聚焦显微镜，α(V)β(3) 与 gB(RGD) 和 KSHV 病毒粒子结合，证明了直接的受体-配体相互作用。特异性α(V)β(3)拮抗剂，包括环状和双环RGD肽以及α(V)β(3)功能阻断抗体，可抑制KSHV感染70%至80%。来自缺乏 alpha(3)beta(1) 的 alpha(3) 缺失小鼠的角质形成细胞完全能够感染 KSHV，并且通过转染 alpha(3) cDNA 重建 alpha(3)beta(1) 功能可将 KSHV 感染性从 74% 降低至 55%。检测到α(3)β(1)对细胞表面α(V)β(3)表达和α(V)β(3)介导的过表达α(3)β(1)的α(3)-CHO细胞粘附的额外抑制作用，这与之前关于α(3)β(1)对α(V)β(3)功能的反显性抑制的报道一致。这些观察结果可能解释了先前有关可溶性 α(3)β(1) 抑制 KSHV 感染的报道。我们的研究表明，α(V)β(3) 是一种细胞受体，通过结合病毒粒子相关的 gB(RGD) 介导 KSHV 的细胞粘附和进入靶细胞。
Kaposi's sarcoma-associated herpesvirus (KSHV) envelope-associated glycoprotein B (gB) is involved in the initial steps of binding to host cells during KSHV infection. gB contains an RGD motif reported to bind the integrin alpha(3)beta(1), during virus entry. Although the ligand specificity of alpha(3)beta(1) has been controversial, current literature indicates that alpha(3)beta(1) ligand recognition is independent of RGD. We compared alpha(3)beta(1) to the RGD-binding integrin, alpha(V)beta(3), for binding to envelope-associated gB and a gB(RGD) peptide. Adhesion assays demonstrated that beta(3)-CHO cells overexpressing alpha(V)beta(3) specifically bound gB(RGD), whereas alpha(3)-CHO cells overexpressing alpha(3)beta(1) did not. Function-blocking antibodies to alpha(V)beta(3) inhibited the adhesion of HT1080 fibro-sarcoma cells to gB(RGD), while antibodies to alpha(3)beta(1) did not. Using affinity-purified integrins and confocal microscopy, alpha(V)beta(3) bound to gB(RGD) and KSHV virions, demonstrating direct receptor-ligand interactions. Specific alpha(V)beta(3) antagonists, including cyclic and dicyclic RGD peptides and alpha(V)beta(3) function-blocking antibodies, inhibited KSHV infection by 70 to 80%. Keratinocytes from alpha(3)-null mice lacking alpha(3)beta(1) were fully competent for infection by KSHV, and reconstitution of alpha(3)beta(1) function by transfection with alpha(3) cDNA reduced KSHV infectivity from 74% to 55%. Additional inhibitory effects of alpha(3)beta(1) on the cell surface expression of alpha(V)beta(3) and on alpha(V)beta(3)-mediated adhesion of alpha(3)-CHO cells overexpressing alpha(3)beta(1) were detected, consistent with previous reports of transdominant inhibition of alpha(V)beta(3) function by alpha(3)beta(1). These observations may explain previous reports of an inhibition of KSHV infection by soluble alpha(3)beta(1). Our studies demonstrate that alpha(V)beta(3) is a cellular receptor mediating both the cell adhesion and entry of KSHV into target cells through binding the virion-associated gB(RGD).