RRC ID 52511
Author Kaito Y, Kataoka R, Mihara T, Takechi K, Takahira A, Watanabe S, Han F, Tamura M.
Title Phosphorylation of Ser-525 in βPix impairs Nox1-activating ability in Caco-2 cells.
Journal Arch Biochem Biophys
Abstract βPix activates Nox1, an O2--generating NADPH oxidase, through Rac activation. In this study, we found that S525E mutation of βPix eliminated its Nox1-activating ability in transfected Caco-2 cells. Unexpectedly, affinity for Rac was not diminished but rather enhanced by S525E mutation, and guanine nucleotide exchange factor (GEF) activity was not altered. The N-terminal fragment (amino acids 1-400) showed similar Rac-binding and GEF activity to wild-type βPix. In contrast, the C-terminal fragment (amino acids 408-646) had higher Rac-binding activity, particularly for Rac-GTP, than wild-type βPix, and showed no GEF activity. These data suggest that a second Rac-binding site within the C-terminal region is opened by phosphorylation of Ser-525. The site may bind not only Rac-GDP but also Rac-GTP released from the N-terminal catalytic region, which interrupts Rac-GTP translocation to the membrane where Nox1 resides. If one considers that S340E mutation enhances Nox1 activation (Kaito et al., 2014), the present study suggests that βPix can also play an inhibitory role in O2- production, depending on the sites of phosphorylation.
Volume 638
Pages 58-65
Published 2018-1-15
DOI 10.1016/j.abb.2017.12.010
PII S0003-9861(17)30605-7
PMID 29242061
MeSH Amino Acid Substitution Caco-2 Cells Enzyme Activation / genetics Humans Mutation, Missense* NADPH Oxidase 1 / genetics NADPH Oxidase 1 / metabolism* Phosphorylation / genetics Protein Domains Rho Guanine Nucleotide Exchange Factors / genetics Rho Guanine Nucleotide Exchange Factors / metabolism* Superoxides / metabolism* rac GTP-Binding Proteins / genetics rac GTP-Binding Proteins / metabolism
IF 3.391
Times Cited 0
Resource
Human and Animal Cells CACO-2(RCB0988)