Nox1 activation by βPix and the role of Ser-340 phosphorylation

Yuuki Kaito; Ryosuke Kataoka; Kento Takechi; Tatsuya Mihara; Minoru Tamura

doi:10.1016/j.febslet.2014.04.025

Nox1 activation by βPix and the role of Ser-340 phosphorylation

FEBS Lett. 2014 May 29;588(11):1997-2002. doi: 10.1016/j.febslet.2014.04.025. Epub 2014 Apr 30.

Authors

Yuuki Kaito¹, Ryosuke Kataoka¹, Kento Takechi¹, Tatsuya Mihara¹, Minoru Tamura²

Affiliations

¹ Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
² Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan. Electronic address: tamura@ehime-u.ac.jp.

PMID: 24792722
DOI: 10.1016/j.febslet.2014.04.025

Abstract

Rac is an activating factor for Nox1, an O2(-)-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 O2(-) production in resting cells and cells stimulated with EGF or phorbol ester. βPix(S340E) further enhanced O2(-) 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.

Keywords: Nox1; Noxa1; Noxo1; Phosphorylation; Superoxide; βPix.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adaptor Proteins, Signal Transducing
Adaptor Proteins, Vesicular Transport / metabolism
Amino Acid Sequence
Amino Acid Substitution
Caco-2 Cells
Enzyme Activation
Epidermal Growth Factor / physiology
Guanosine Triphosphate / chemistry
Humans
Hydrolysis
Mutagenesis, Site-Directed
NADPH Oxidase 1
NADPH Oxidases / metabolism*
Phosphorylation
Protein Binding
Protein Processing, Post-Translational*
Rho Guanine Nucleotide Exchange Factors / chemistry
Rho Guanine Nucleotide Exchange Factors / genetics
Rho Guanine Nucleotide Exchange Factors / metabolism*
Serine / metabolism
Superoxides / metabolism
rac GTP-Binding Proteins / chemistry

Substances

Adaptor Proteins, Signal Transducing
Adaptor Proteins, Vesicular Transport
NOXA1 protein, human
NOXO1 protein, human
Rho Guanine Nucleotide Exchange Factors
Superoxides
Serine
Epidermal Growth Factor
Guanosine Triphosphate
NADPH Oxidase 1
NADPH Oxidases
NOX1 protein, human
rac GTP-Binding Proteins