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J Cell Biol. 2008 May 19;181(4):683-95. doi: 10.1083/jcb.200711165. Epub 2008 May 12.

The tight junction protein complex undergoes rapid and continuous molecular remodeling at steady state.

Author information

1
Department of Pathology, The University of Chicago, Chicago, IL 60637, USA.

Abstract

The tight junction defines epithelial organization. Structurally, the tight junction is comprised of transmembrane and membrane-associated proteins that are thought to assemble into stable complexes to determine function. In this study, we measure tight junction protein dynamics in live confluent Madin-Darby canine kidney monolayers using fluorescence recovery after photobleaching and related methods. Mathematical modeling shows that the majority of claudin-1 (76 +/- 5%) is stably localized at the tight junction. In contrast, the majority of occludin (71 +/- 3%) diffuses rapidly within the tight junction with a diffusion constant of 0.011 microm(2)s(-1). Zonula occludens-1 molecules are also highly dynamic in this region, but, rather than diffusing within the plane of the membrane, 69 +/- 5% exchange between membrane and intracellular pools in an energy-dependent manner. These data demonstrate that the tight junction undergoes constant remodeling and suggest that this dynamic behavior may contribute to tight junction assembly and regulation.

PMID:
18474622
PMCID:
PMC2386107
DOI:
10.1083/jcb.200711165
[Indexed for MEDLINE]
Free PMC Article

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