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The Oligomerization of the Coiled Coil‐domain of Occluddin Is Redox Sensitive
Author(s) -
Walter Juliane K.,
Rueckert Christine,
Voss Martin,
Mueller S.L.,
Piontek Jörg,
Gast Klaus,
Blasig Ingolf E.
Publication year - 2009
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2009.04058.x
Subject(s) - chemistry , biophysics , occludin , coiled coil , redox , cytosol , biochemistry , transmembrane protein , protein structure , tight junction , microbiology and biotechnology , biology , enzyme , receptor , organic chemistry
The transmembrane tight junction protein occludin is sensitive to oxidative stress. Occludin oligomerizes; however, its function in the tight junction is unknown. The cytosolic C‐terminal tail contains a coiled coil‐domain and forms dimers contributing to the oligomerization. The regulation of the oligomerization remains unclear. As the domain area contains sulfhydryl residues, we tested the hypothesis that the dimerization of the coiled coil‐domain depends on these residues. We showed that the dimerization is modulated by the thiol concentration in the low‐millimolar range, which is relevant both for physiological and pathophysiological conditions. Masking the sulfhydryl residues in the fragment by covalent binding of 4‐vinyl pyridine prevented the dimerization but did not affect its helical structure and cylindric shape. The data demonstrate, for the first time, that disulfide bridge formation of murine cystein 408 is involved in the dimerization. This process is redox‐sensitive but the secondary structure of the domain is not. It is concluded that the dimerization of occludin may play a regulatory role in the tight junction assembly under physiological and pathological conditions.