TY  - JOUR
A1  - Blasig, Ingolf E.
A1  - Winkler, Lars
A1  - Lassowski, Birgit
A1  - Müller, Sandra L.
A1  - Zuleger, Nikolaj
A1  - Krause, Eberhard
A1  - Krause, Gerd
A1  - Gast, Klaus
A1  - Kolbe, Michael
A1  - Piontek, Jörg
T1  - On the self-association potential of transmembrane tight junction proteins
N2  - Tight junctions seal intercellular clefts via membrane-related strands, hence, maintaining important organ functions. We investigated the self-association of strand-forming transmembrane tight junction proteins. The regulatory tight junction protein occludin was differently tagged and cotransfected in eucaryotic cells. These occludins colocalized within the plasma membrane of the same cell, coprecipitated and exhibited fluorescence resonance energy transfer. Differently tagged strand-forming claudin-5 also colocalized in the plasma membrane of the same cell and showed fluorescence resonance energy transfer. This demonstrates self-association in intact cells both of occludin and claudin-5 in one plasma membrane. In search of dimerizing regions of occludin, dimerization of its cytosolic C-terminal coiled-coil domain was identified. In claudin-5, the second extracellular loop was detected as a dimer. Since the transmembrane junctional adhesion molecule also is known to dimerize, the assumption that homodimerization of transmembrane tight junction proteins may serve as a common structural feature in tight junction assembly is supported
Y1  - 2006
UR  - http://www.springerlink.com/content/101193
U6  - https://doi.org/10.1007/s00018-005-5472-x
SN  - 1420-682X
ER  - 
TY  - JOUR
A1  - Walter, Juliane K.
A1  - Castro, Victor Manuel
A1  - Voss, Martin
A1  - Gast, Klaus
A1  - Rueckert, Christine
A1  - Piontek, Jörg
A1  - Blasig, Ingolf E.
T1  - Redox-sensitivity of the dimerization of occludin
N2  - Occludin is a self-associating transmembrane tight junction protein affected in oxidative stress. However, its function is unknown. The cytosolic C-terminal tail contains a coiled coil-domain forming dimers contributing to the self- association. Studying the hypothesis that the self-association is redox-sensitive, we found that the dimerization of the domain depended on the sulfhydryl concentration of the environment in low-millimolar range. Under physiological conditions, monomers and dimers were detected. Masking the sulfhydryl residues in the domain prevented the dimerization but affected neither its helical structure nor cylindric shape. Incubation of cell extracts containing full-length occludin with sulfhydryl reagents prevented the dimerization; a cysteine/alanine exchange mutant also did not show dimer formation. This demonstrates, for the first time, that disulfide bridge formation of the domain is involved in the occludin dimerization. It is concluded that the redox-dependent dimerization of occludin may play a regulatory role in the tight junction assembly under physiological and pathological conditions.
Y1  - 2009
UR  - http://www.springerlink.com/content/101193
U6  - https://doi.org/10.1007/s00018-009-0150-z
SN  - 1420-682X
ER  -