Reovirus binding determinants in junctional adhesion molecule-A
Reovirus binding determinants in junctional adhesion molecule-A
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DOI：
10.1074/jbc.m702180200
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发表时间：
2007-06-15
影响因子：
4.8
通讯作者：
Dermody, Terence S.
中科院分区：
文献类型：
--
作者：
Guglielmi, Kristen M.;Kirchner, Eva;Dermody, Terence S.
连接粘附分子-A（JAM-A）作为哺乳动物正呼肠孤病毒（呼肠孤病毒）的非依赖于病毒型的受体。JAM-A的膜远端免疫球蛋白样D1结构域是同源二聚化和结合呼肠孤病毒附着蛋白sigma 1所必需的。我们采用JAM-A二聚体界面的结构指导突变分析来鉴定呼肠孤病毒结合的决定因素。我们纯化突变型JAM-A胞外域用于液相和表面等离子体共振结合研究，并在中国仓鼠卵巢细胞中表达全长JAM-A的突变形式以评估呼肠孤病毒结合和感染性。JAM-A二聚体界面中参与盐桥或氢键与并列JAM-A单体相互作用的残基的突变消除了JAM-A形成二聚体的能力。不能形成二聚体的JAM-A突变体与σ 1头部形成复合物，其与野生型JAM-A-σ 1头部复合物不可区分，表明σ 1结合至JAM-A单体。二聚体界面中β链C的残基Glu（61）和Lys（63）以及β链C'的残基Leu（72）是3型菌株Dearing sigma 1的有效JAM-A接合所需的。相邻残基的突变改变了σ 1-JAM-A结合相互作用的动力学。原型呼肠孤病毒株1型Lang和2型Jones与3型Dearing具有相似但不相同的结合要求。这些结果表明，呼肠孤病毒通过主要在二聚体界面的β链C和C'上发现的残基接合JAM-A单体，并提高了在用不同的呼肠孤病毒株感染后在小鼠中产生的不同疾病表型部分归因于与JAM-A接触的差异的可能性。
Junctional adhesion molecule-A (JAM-A) serves as a serotype-independent receptor for mammalian orthoreoviruses (reoviruses). The membrane-distal immunoglobulin-like D1 domain of JAM-A is required for homodimerization and binding to reovirus attachment protein sigma 1. We employed a structure-guided mutational analysis of the JAM-A dimer interface to identify determinants of reovirus binding. We purified mutant JAM-A ectodomains for solution-phase and surface plasmon resonance binding studies and expressed mutant forms of full-length JAM-A in Chinese hamster ovary cells to assess reovirus binding and infectivity. Mutation of residues in the JAM-A dimer interface that participate in salt-bridge or hydrogen-bond interactions with apposing JAM-A monomers abolishes the capacity of JAM-A to form dimers. JAM-A mutants incapable of dimer formation form complexes with the sigma 1 head that are indistinguishable from wild-type JAM-A-sigma 1 head complexes, indicating that sigma 1 binds to JAM-A monomers. Residues Glu(61) and Lys(63) of beta-strand C and Leu(72) of beta-strand C' in the dimer interface are required for efficient JAM-A engagement of strain type 3 Dearing sigma 1. Mutation of neighboring residues alters the kinetics of the sigma 1-JAM-A binding interaction. Prototype reovirus strains type 1 Lang and type 2 Jones share similar, although not identical, binding requirements with type 3 Dearing. These results indicate that reovirus engages JAM-A monomers via residues found mainly on beta-strands C and C' of the dimer interface and raise the possibility that the distinct disease phenotypes produced in mice following infection with different strains of reovirus are in part attributable to differences in contacts with JAM-A.