Cell Biology

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Science  02 May 2003:
Vol. 300, Issue 5620, pp. 703-705
DOI: 10.1126/science.300.5620.703d

Internal layers of epithelial cells can serve not only as barriers between fluid compartments as in the cardiovascular and gastrointestinal systems, but also as obstructions to foreign agents, such as viruses.

Nevertheless, it is necessary to incorporate mechanisms for passing molecules (cytokines) and cells (leukocytes) across these barriers to deal with inflammatory responses, and this requires regulated and reversible disassembly of the intercellular barriers. The integral membrane protein junctional adhesion molecule (JAM) forms oligomeric assemblies at tight junctions between epithelial cells. Prota et al. describe the high-resolution structure of the extracellular portion of human JAM1 and propose that the differences in monomer-monomer contacts between mouse and human JAM reveal potential sites of dissociation. Unfortunately, it appears that viruses have targeted these same sites. The adenovirus fiber protein is known to infect by binding to the cellular coxsackievirus and adenovirus receptor (CAR), the structures of JAM and CAR are similar, and the attachment protein s1 of reovirus and the fiber protein of adenovirus are structurally similar as well.—GJC

Proc. Natl. Acad. Sci. U.S.A. 100, 5366 (2003).

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