Premium
Binding of the PX domain of p47 phox to phosphatidylinositol 3,4‐bisphosphate and phosphatidic acid is masked by an intramolecular interaction
Author(s) -
Karathanassis Dimitrios,
Stahelin Robert V.,
Bravo Jerónimo,
Perisic Olga,
Pacold Christine M,
Cho Wonhwa,
Williams Roger L
Publication year - 2002
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdf519
Subject(s) - phosphatidylinositol 4,5 bisphosphate , biology , phosphatidic acid , phosphatidylinositol , intramolecular force , pleckstrin homology domain , biochemistry , domain (mathematical analysis) , biophysics , microbiology and biotechnology , stereochemistry , signal transduction , phospholipid , chemistry , membrane , mathematical analysis , mathematics
p47 phox is a key cytosolic subunit required for activation of phagocyte NADPH oxidase. The X‐ray structure of the p47 phox PX domain revealed two distinct basic pockets on the membrane‐binding surface, each occupied by a sulfate. These two pockets have different specificities: one preferentially binds phosphatidylinositol 3,4‐bisphosphate [PtdIns(3,4)P 2 ] and is analogous to the phophatidylinositol 3‐phosphate (PtdIns3P)‐binding pocket of p40 phox , while the other binds anionic phospholipids such as phosphatidic acid (PtdOH) or phosphatidylserine. The preference of this second site for PtdOH may be related to previously observed activation of NADPH oxidase by PtdOH. Simultaneous occupancy of the two phospholipid‐binding pockets radically increases membrane affinity. Strikingly, measurements for full‐length p47 phox show that membrane interaction by the PX domain is masked by an intramolecular association with the C‐terminal SH3 domain (C‐SH3). Either a site‐specific mutation in C‐SH3 (W263R) or a mimic of the phosphorylated form of p47 phox [Ser(303, 304, 328, 359, 370)Glu] cause a transition from a closed to an open conformation that binds membranes with a greater affinity than the isolated PX domain.