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The cell polarity protein ASIP/PAR‐3 directly associates with junctional adhesion molecule (JAM)
Author(s) -
Ebnet Klaus,
Suzuki Atsushi,
Horikoshi Yosuke,
Hirose Tomonori,
Meyer zu Brickwedde MariaKatharina,
Ohno Shigeo,
Vestweber Dietmar
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.14.3738
Subject(s) - microbiology and biotechnology , biology , cdc42 , cell polarity , tight junction , cell junction , asymmetric cell division , polarity (international relations) , cell adhesion , intracellular , cell division , multicellular organism , cell , gtpase , biochemistry
The establishment and maintenance of cellular polarity are critical for the development of multicellular organisms. PAR (partitioning‐defective) proteins were identified in Caenorhabditis elegans as determinants of asymmetric cell division and polarized cell growth. Recently, vertebrate orthologues of two of these proteins, ASIP/PAR‐3 and PAR‐6, were found to form a signalling complex with the small GTPases Cdc42/Rac1 and with atypical protein kinase C (PKC). Here we show that ASIP/PAR‐3 associates with the tight‐junction‐associated protein junctional adhesion molecule (JAM) in vitro and in vivo . No binding was observed with claudin‐1, ‐4 or ‐5. In fibroblasts and CHO cells overexpressing JAM, endogenous ASIP is recruited to JAM at sites of cell–cell contact. Over expression of truncated JAM lacking the extracellular part disrupts ASIP/PAR‐3 localization at intercellular junctions and delays ASIP/PAR‐3 recruitment to newly formed cell junctions. During junction formation, JAM appears early in primordial forms of junctions. Our data suggest that the ASIP/PAR‐3–aPKC complex is tethered to tight junctions via its association with JAM, indicating a potential role for JAM in the generation of cell polarity in epithelial cells.