Structural highlights
Function[SIGM1_REOVD] Fiber-like molecule that attaches the virion to the host cell membrane by binding to the primary receptor F11R/JAM-A and to sialic acid containing proteins (coreceptor). The interaction of sigma-1 with F11R is required for NF-kB activation and apoptosis. Binding to both sialic acid and F11R is required to induce maximal levels of apoptosis. [JAM1_HUMAN] Seems to play a role in epithelial tight junction formation. Appears early in primordial forms of cell junctions and recruits PARD3. The association of the PARD6-PARD3 complex may prevent the interaction of PARD3 with JAM1, thereby preventing tight junction assembly (By similarity). Plays a role in regulating monocyte transmigration involved in integrity of epithelial barrier. Involved in platelet activation. In case of orthoreovirus infection, serves as receptor for the virus. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedViral attachment to specific host receptors is the first step in viral infection and serves an essential function in the selection of target cells. Mammalian reoviruses are highly useful experimental models for studies of viral pathogenesis and show promise as vectors for oncolytics and vaccines. Reoviruses engage cells by binding to carbohydrates and the immunoglobulin superfamily member, junctional adhesion molecule-A (JAM-A). JAM-A exists at the cell surface as a homodimer formed by extensive contacts between its N-terminal immunoglobulin-like domains. We report the crystal structure of reovirus attachment protein sigma1 in complex with a soluble form of JAM-A. The sigma1 protein disrupts the JAM-A dimer, engaging a single JAM-A molecule via virtually the same interface that is used for JAM-A homodimerization. Thus, reovirus takes advantage of the adhesive nature of an immunoglobulin-superfamily receptor by usurping the ligand-binding site of this molecule to attach to the cell surface. The dissociation constant (K(D)) of the interaction between sigma1 and JAM-A is 1,000-fold lower than that of the homophilic interaction between JAM-A molecules, indicating that JAM-A strongly prefers sigma1 as a ligand. Analysis of reovirus mutants engineered by plasmid-based reverse genetics revealed residues in sigma1 required for binding to JAM-A and infectivity of cultured cells. These studies define biophysical mechanisms of reovirus cell attachment and provide a platform for manipulating reovirus tropism to enhance vector targeting. Structure of reovirus sigma1 in complex with its receptor junctional adhesion molecule-A.,Kirchner E, Guglielmi KM, Strauss HM, Dermody TS, Stehle T PLoS Pathog. 2008 Dec;4(12):e1000235. Epub 2008 Dec 12. PMID:19079583[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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