Cryptic Rac-binding and p21(Cdc42Hs/Rac)-activated kinase phosphorylation sites of NADPH oxidase component p67(phox)

• Published in: The Journal of biological chemistry 1998-06, Vol.273 (25), p.15693-15701
• Main Authors: Ahmed, S, Prigmore, E, Govind, S, Veryard, C, Kozma, R, Wientjes, F B, Segal, A W, Lim, L
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Amino Acid Sequence; Animals; Binding Sites; cdc42 GTP-Binding Protein; Cell Cycle Proteins - metabolism; GTP Phosphohydrolases - metabolism; GTP-Binding Proteins - metabolism; Mice; Molecular Sequence Data; NADPH Oxidases - metabolism; p21-Activated Kinases; Peptide Fragments - metabolism; Peptides - metabolism; Phosphoproteins - metabolism; Phosphorylation; Protein Folding; Protein-Serine-Threonine Kinases - metabolism; rac GTP-Binding Proteins; src Homology Domains
• ISSN: 0021-9258
• DOI: 10.1074/jbc.273.25.15693

Rac1 is a member of the Rho family of small molecular mass GTPases that act as molecular switches to control actin-based cell morphology as well as cell growth and differentiation. Rac1 and Rac2 are specifically required for superoxide formation by components of the NADPH oxidase. In binding assays, Rac1 interacts directly with p67(phox), but not with the other oxidase components: cytochrome b, p40(phox), or p47(phox) (Prigmore, E., Ahmed, S., Best, A., Kozma, R. , Manser, E., Segal, A. W., and Lim, L. (1995) J. Biol. Chem. 270, 10717-10722). Here, the Rac1/2 interaction with p67(phox) has been characterized further. Rac1 and Rac2 can bind to p67(phox) amino acid residues 170-199, and the N terminus (amino acids 1-192) of p67(phox) can be used as a specific inhibitor of Rac signaling. Deletion of p67(phox) C-terminal sequences (amino acids 193-526), the C-terminal SH3 domain (amino acids 470-526), or the polyproline-rich motif (amino acids 226-236) stimulates Rac1 binding by approximately 8-fold. p21(Cdc42Hs/Rac)-activated kinase (PAK) phosphorylates p67(phox) amino acid residues adjacent to the Rac1/2-binding site, and this phosphorylation is stimulated by deletion of the C-terminal SH3 domain or the polyproline-rich motif. These data suggest a role for cryptic Rac-binding and PAK phosphorylation sites of p67(phox) in control of the NADPH oxidase.