The Unique-5 and -6 Motifs of ZO-1 Regulate Tight Junction Strand Localization and Scaffolding Properties
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Date
2006
Authors
Fanning, Alan S.
Little, Brent P.
Rahner, Christoph
Utepbergenov, Darkhan
Walther, Zenta
Anderson, James M.
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Abstract
The proper cellular location and sealing of tight junctions is assumed to depend on scaffolding properties of ZO-1, a member of the MAGUK protein family. ZO-1 contains a conserved SH3-GUK module that is separated by a variable region (unique-5), which in other MAGUKs has proven regulatory functions. To identify motifs in ZO-1 critical for its
putative scaffolding functions, we focused on the SH3-GUK module including unique-5 (U5) and unique-6 (U6), a motif immediately C-terminal of the GUK domain. In vitro binding studies reveal U5 is sufficient for occludin binding; U6 reduces the affinity of this binding. In cultured cells, U5 is required for targeting ZO-1 to tight junctions and removal of U6 results in ectopically displaced junction strands containing the modified ZO-1, occludin, and claudin on the lateral cell membrane. These results provide evidence that ZO-1 can control the location of tight junction transmembrane proteins and reveals complex protein binding and targeting signals within its SH3-U5-GUK-U6 region. We review these findings in the context of regulated scaffolding functions of other MAGUK proteins
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Keywords
Research Subject Categories::NATURAL SCIENCES::Chemistry, MAGUK protein
Citation
Alan S. Fanning, Brent P. Little, Christoph Rahner, Darkhan Utepbergenov, Zenta Walther, and James M. Anderson; 2006; The Unique-5 and -6 Motifs of ZO-1 Regulate Tight Junction Strand Localization and Scaffolding Properties; Molecular Biology of the Cell