Sequential activation of phosphatidylinositol 3-kinase, beta Pix, Rac1, and Nox1 in growth factor-induced production of H2O2.
The generation of reactive oxygen species (ROS) in cells stimulated with growth factors requires the activation of phosphatidylinositol 3-kinase (PI3K) and the Rac protein. We report here that the COOH-terminal region of Nox1, a protein related to gp91(phox) (Nox2) of phagocytic cells, is constitutively associated with beta Pix, a guanine nucleotide exchange factor for Rac. Both growth factor-induced ROS production and Rac1 activation were completely blocked in cells depleted of beta Pix by RNA interference. Rac1 was also shown to bind to the COOH-terminal region of Nox1 in a growth factor-dependent manner. Moreover, the depletion of Nox1 by RNA interference inhibited growth factor-induced ROS generation. These results suggest that ROS production in growth factor-stimulated cells is mediated by the sequential activation of PI3K, beta Pix, and Rac1, which then binds to Nox1 to stimulate its NADPH oxidase activity.
Park
Hye Sun
HS
Center for Cell Signaling Research, Division of Molecular Life Sciences, Ewha Womans University, Seoul 120-750, Korea.
Lee
Seung Hye
SH
Park
Dongeun
D
Lee
Jun Sung
JS
Ryu
Sung Ho
SH
Lee
Won Jae
WJ
Rhee
Sue Goo
SG
Bae
Yun Soo
YS
D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D018938:Caco-2 Cells; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D009154:Mutation; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D064067:Rho Guanine Nucleotide Exchange Factors; D014162:Transfection; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
C576606:ARHGEF7 protein, human; D018797:Cell Cycle Proteins; D020662:Guanine Nucleotide Exchange Factors; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; D004815:Epidermal Growth Factor; D006861:Hydrogen Peroxide; D000074624:NADPH Oxidase 1; D019255:NADPH Oxidases; C402799:NOX1 protein, human; D019869:Phosphatidylinositol 3-Kinases; D020830:rac1 GTP-Binding Protein