Crystal structure of human junctional adhesion molecule 1: Implications for reovirus binding

Abstract

Reovirus attachment to cells is mediated by the binding of viral attachment protein 1 to junctional adhesion molecule 1 (JAM1). The crystal structure of the extracellular region of human JAM1 (hJAM1) reveals two concatenated Ig-type domains with a pronounced bend at the domain interface. Two hJAM1 molecules form a dimer that is stabilized by extensive ionic and hydrophobic contacts between the N-terminal domains. This dimeric arrangement is similar to that observed previously in the murine homolog of JAM1, indicating physiologic relevance. However, differences in the dimeric structures of hJAM1 and murine JAM1 suggest that the interface is dynamic, perhaps as a result of its ionic nature. We demonstrate that hJAM1, but not the related proteins hJAM2 and hJAM3, serves as a reovirus receptor, which provides insight into sites in hJAM1 that likely interact with 1. In addition, we present evidence that the previously reported structural homology between 1 and the adenovirus attachment protein, fiber, also extends to their respective receptors, which form similar dimeric structures. Because both receptors are located at regions of cellcell contact, this similarity suggests that reovirus and adenovirus use conserved mechanisms of entry and pathways of infection.

Involvement of the Junctional Adhesion Molecule-1 (JAM1) Homodimer Interface in Regulation of Epithelial Barrier Function

“…Mutant protein production was verified by assaying the culture medium for alkaline phosphatase activity and by reactivity with JAM1 mAb 1H2A9. For homodimerization assays, JAM1 was produced in bacteria as reported previously (17). Dr. Terence Dermody kindly provided a plasmid encoding GST fused to the extracellular domain of JAM1 (GST-JAM1).…”

“…The N-terminal D1 domain is formed by two antiparallel ␤-sheets consisting of strands ABEF and GFCCЈCЉ. According to the crystal structure, interactions between the GFCCЈ faces of D1 domains of adjacent JAM1 molecules facilitate formation of stable homodimers (17). This model of JAM1 homodimer formation was used to investigate the structural basis for the inhibitory effects of J3F.1 and J10.4 on epithelial barrier formation.…”

“…Evidence suggests that homophilic interactions are important for JAM1 function. The crystal structure of JAM1 predicts that it forms stable homodimers (16,17). Cross-linking experiments suggest that JAM1 forms homodimers in solution and on the surface of transfected CHO cells (4).…”

Junctional Adhesion Molecule A Interacts with Afadin and PDZ-GEF2 to Activate Rap1A, Regulate β1 Integrin Levels, and Enhance Cell Migration

“…The membrane distal most extracellular Ig loop mediates homodimerization between JAM-A proteins on the same cell (Prota et al, 2003;Guglielmi et al, 2006;Severson et al, 2008) (cis) and potentially mediates interactions between JAM-A molecules on adjacent cells (Kostrewa et al, 2001) …”

Cloning and preliminary functional studies of the JAM-A gene in grass carp (Ctenopharyngodon idellus)

“…JAM-A regulates the formation of intercellular tight junctions [4] and is involved in platelet activation, leukocyte transmigration and angiogenesis [5,6]. Reovirus recognizes structural features that are present in JAM-A, but not in JAM-B or JAM-C [7]. The crystal structure of the extracellular region of JAM-A reveals the presence of two concatenated Ig-type domains (D1 and D2) with a pronounced bend at the domain interface.…”