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p115 Rho GTPase activating protein interacts with MEKK1
Author(s) -
Christerson Lori B.,
Gallagher Ewen,
Vanderbilt Colleen A.,
Whitehurst Angelique W.,
Wells Clark,
Kazempour Roxana,
Sternweis Paul C.,
Cobb Melanie H.
Publication year - 2002
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.10125
Subject(s) - microbiology and biotechnology , rhoa , cytoskeleton , biology , cdc42 , gtpase activating protein , map kinase kinase kinase , protein kinase a , gtpase , rac gtp binding proteins , signal transduction , kinase , rac1 , genetics , cell , g protein
Mammalian MAP/ERK kinase kinase 1 (MEKK1) was identified as a mammalian homolog of Ste11p of the yeast pheromone‐induced mating pathway. Like Ste11p, MEKK1 is a MAP3 kinase linked to at least two MAP kinase cascades and regulatory events that require cytoskeletal reorganization. MEKK1 is activated by molecules that impact cytoskeletal function. MEKK1−/−cells are defective in cell migration, demonstrating that it is required for cell motility. MEKK1 has a 1,200 residue N‐terminal regulatory domain that interacts with a dozen identified proteins. Using part of the MEKK1 N‐terminus in a yeast two‐hybrid screen, we discovered a novel interaction with p115 Rho GTPase‐activating protein (GAP). The p115 Rho GAP binds to MEKK1 in vitro and in intact cells. The p115 Rho GAP has selectivity for RhoA over other Rho family members. Expression of p115 Rho GAP reduces MEKK1‐induced signaling to AP‐1. The reduced activation of AP‐1 is dependent on the association of MEKK1 with p115 Rho GAP, because deletion of the Rho GAP SH3 domain, which abrogates their interaction, restores the stimulatory effect of MEKK1 on AP‐1 activity. Here we have identified an MEKK1 binding partner that offers a connection between this protein kinase and the machinery regulating cytoskeletal reorganization. © 2002 Wiley‐Liss, Inc.