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Phosphorylation of Noxo1 at threonine 341 regulates its interaction with Noxa1 and the superoxide‐producing activity of Nox1
Author(s) -
Yamamoto Asataro,
Takeya Ryu,
Matsumoto Masaki,
Nakayama Keiichi I.,
Sumimoto Hideki
Publication year - 2013
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.12489
Subject(s) - nox1 , phosphorylation , superoxide , threonine , chemistry , microbiology and biotechnology , biochemistry , biology , serine , enzyme
Superoxide production by Nox1, a member of the Nox family NAPDH oxidases, requires expression of its regulatory soluble proteins Noxo1 (Nox organizer 1) and Noxa1 (Nox activator 1) and is markedly enhanced upon cell stimulation with phorbol 12‐myristate 13‐acetate ( PMA ), a potent activator of protein kinase C ( PKC ). The mechanism underlying PMA ‐induced enhancement of Nox1 activity, however, remains to be elucidated. Here we show that, in response to PMA , Noxo1 undergoes phosphorylation at multiple sites, which is inhibited by the PKC inhibitor GF 109203X. Among them, Thr341 in Noxo1 is directly phosphorylated by PKC in vitro , and alanine substitution for this residue reduces not only PMA ‐induced Noxo1 phosphorylation but also PMA ‐dependent enhancement of Nox1‐catalyzed superoxide production. Phosphorylation of Thr341 allows Noxo1 to sufficiently interact with Noxa1, an interaction that participates in Nox1 activation. Thus phosphorylation of Noxo1 at Thr341 appears to play a crucial role in PMA ‐elicited activation of Nox1, providing a molecular link between PKC ‐mediated signal transduction and Nox1‐catalyzed superoxide production. Furthermore, Ser154 in Noxo1 is phosphorylated in both resting and PMA ‐stimulated cells, and the phosphorylation probably participates in a PMA ‐independent constitutive activity of Nox1. Ser154 may also be involved in protein kinase A ( PKA ) mediated regulation of Nox1; this serine is the major residue that is phosphorylated by PKA in vitro . Thus phosphorylation of Noxo1 at Thr341 and at Ser154 appears to regulate Nox1 activity in different manners. Structured digital abstractNoxo1 binds to p22phox by pull down ( 1 , 2 , 3 ) Noxo1 binds to Noxo1 by pull down ( View interaction ) Noxa1 binds to Noxo1 by pull down ( 1 , 2 , 3 , 4 , 5 )