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Ser373 on Cx43 is phosphorylated by Akt and mediates interaction with 14‐3‐3
Author(s) -
Park Darren,
Freitas Tracey,
Martyn Kendra,
Jin Chengshi,
Lau Alan,
Alam Maqsudul,
WarnCramer Bonnie
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a937-a
Subject(s) - protein kinase b , phosphorylation , microbiology and biotechnology , proto oncogene proteins c akt , chemistry , pten , phosphatase , biology , signal transduction , pi3k/akt/mtor pathway , biochemistry
Connexins (Cxs) form membrane channels for the intercellular exchange of small molecules, ions and second messengers and are regulated by phosphorylation and interacting proteins. 14‐3‐3Θ was identified as an interacting protein by a yeast two‐hybrid screen with the C‐terminal (CT) cytoplasmic domain of Cx43. 14‐3‐3 dimers interact with >200 proteins with functional effects including conformational changes, masking of specific molecular sites, complex assembly and protein localization. Two Cx43 “mode‐1” 14‐3‐3 interaction sites (RXXpS/pTXP), Ser373 (S373) and S244, are conserved across species. Modeling studies support phosphorylation‐dependent binding of S373 to 14‐3‐3Θ. A direct interaction was confirmed by GST pull‐downs and required S373, but not S244 of Cx43. S373 fits a consensus sequence for Akt phosphorylation (R‐X‐R‐X‐X‐pS/pT) and is a target for Akt in vitro . Cx43 co‐localized with 14‐3‐3Θ and Akt in stimulated cells and was pulled down by GST‐14‐3‐3Θ and recognized by Akt‐substrate and 14‐3‐3 motif antibodies. Akt did not appear to be involved in the growth factor‐induced disruption of channel function. These studies support Akt as a kinase that targets Cx43 to an interaction with 14‐3‐3 that may lead to changes in Cx43's conformation or it's interactions with other proteins. The PTEN phosphatase regulates Akt and is mutated or inactivated in some cancers, suggesting a role for Akt in deregulated cell growth and survival. Akt may also play a role in regulating the growth‐suppressor, Cx43, by promoting an interaction with 14‐3‐3.