Binding of the PX domain of p47phox to phosphatidylinositol 3, 4-bisphosphate and phosphatidic acid is masked by an intramolecular interaction

Dimitrios Karathanassis, Robert V. Stahelin, Jerónimo Bravo, Olga Perisic, Christine M. Pacold, Wonhwa Cho, Roger L. Williams

Research output: Contribution to journalArticle

233 Scopus citations

Abstract

p47phox is a key cytosolic subunit required for activation of phagocyte NADPH oxidase. The X-ray structure of the p47phox 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)P2] and is analogous to the phophatidylinositol 3-phosphate (PtdIns3P)-binding pocket of p40phox, 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 phospholipidbinding pockets radically increases membrane affinity. Strikingly, measurements for full-length p47phox 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 p47phox [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.

Original languageEnglish (US)
Pages (from-to)5057-5068
Number of pages12
JournalEMBO Journal
Volume21
Issue number19
DOIs
StatePublished - Oct 1 2002

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Keywords

  • NADPH oxidase
  • Phagocyte
  • Phosphatidic acid
  • Phosphoinositide
  • SH3 domains
  • p40

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

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