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Nox1 activation by βPix and the role of Ser‐340 phosphorylation
Author(s) -
Kaito Yuuki,
Kataoka Ryosuke,
Takechi Kento,
Mihara Tatsuya,
Tamura Minoru
Publication year - 2014
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2014.04.025
Subject(s) - nox1 , transfection , phosphorylation , guanine nucleotide exchange factor , microbiology and biotechnology , nadph oxidase , cell culture , gtp' , phorbol , chemistry , endogeny , protein kinase c , gtpase , biology , biochemistry , reactive oxygen species , gene , enzyme , genetics
Rac is an activating factor for Nox1, an O 2 − ‐generating NADPH oxidase, expressed in the colon and other tissues. Rac requires a GDP‐GTP exchange factor for activation. Nox1 activation by βPix has been demonstrated in cell lines. We examined the effects of βPix and its phosphomimetic mutant on endogenous Nox1 in Caco‐2 cells transfected with Noxo1 and Noxa1. βPix expression enhanced O 2 − production in resting cells and cells stimulated with EGF or phorbol ester. βPix(S340E) further enhanced O 2 − production, while βPix(S340A) eliminated the βPix effect. βPix(S340E), but not βPix(S340A), had higher affinity and GEF activity for Rac than wild‐type βPix. These results suggest that βPix phosphorylation at Ser‐340 upregulates Nox1 through Rac activation, confirming Rac as a trigger for acute Nox1‐dependent ROS production.