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Identification of an actin‐binding site in p47 phox an organizer protein of NADPH oxidase
Author(s) -
Tamura Minoru,
Itoh Katsunori,
Akita Hiroshi,
Takano Keiko,
Oku Satoshi
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.11.080
Subject(s) - actin , mutant , actin binding protein , binding site , biology , biochemistry , phosphorylation , microbiology and biotechnology , peptide sequence , nadph oxidase , wild type , oxidase test , chemistry , actin cytoskeleton , cytoskeleton , enzyme , gene , cell
Actin has been reported to enhance the superoxide‐generating activity of neutrophil NADPH oxidase in a cell‐free system and to interact with p47 phox , a regulatory subunit of the oxidase. In the present study, we searched for an actin‐binding site in p47 phox by far‐western blotting and blot‐binding assays using truncated forms of p47 phox . The amino‐acid sequence 319–337 was identified as an actin‐binding site, and a synthetic peptide of this sequence bound to actin. The sequence shows no homology to other known actin‐binding motifs. It is located in the autoinhibitory region of p47 phox and includes Ser‐328, a phosphorylation site essential for unmasking. Although a phosphorylation‐mimetic p47 phox mutant bound to actin with a lower affinity than the wild type, the same mutant interacted with filamentous actin more efficiently than the wild type. A mutant peptide p47 phox (319–337, Ser328Glu) bound to filamentous actin more tightly than to monomer actin. These results suggest that p47 phox moves to cortical actin when it becomes unmasked in the cells.