PX domain

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PX domain of NADH oxidase (p40phox), lipid-bound
OPM superfamily57
OPM protein1xte

The PX domain is a phosphoinositide-binding structural domain involved in targeting of proteins to cell membranes.

This domain was first found in P40phox and p47phox domains of NADPH oxidase (phox stands for phagocytic oxidase).[1][2] It was also identified in many other proteins involved in membrane trafficking, including nexins, Phospholipase D, and phosphoinositide-3-kinases.

The PX domain is structurally conserved in eukaryotes, although amino acid sequences show little similarity.[3] PX domains interact primarily with PtdIns(3)P lipids.[4][5] However some of them bind to phosphatidic acid, PtdIns(3,4)P2, PtdIns(3,5)P2, PtdIns(4,5)P2, and PtdIns(3,4,5)P3. The PX-domain can also interact with other domains and proteins.

Human proteins containing this domain[edit]

Sorting nexins contain this domain. Other examples include:


  1. ^ Ponting CP (November 1996). "Novel domains in NADPH oxidase subunits, sorting nexins, and PtdIns 3-kinases: binding partners of SH3 domains?". Protein Sci. 5 (11): 2353–7. doi:10.1002/pro.5560051122. PMC 2143296. PMID 8931154.
  2. ^ Wishart MJ, Taylor GS, Dixon JE (June 2001). "Phoxy lipids: revealing PX domains as phosphoinositide binding modules". Cell. 105 (7): 817–20. doi:10.1016/S0092-8674(01)00414-7. PMID 11439176.
  3. ^ Hiroaki H, Ago T, Ito T, Sumimoto H, Kohda D (June 2001). "Solution structure of the PX domain, a target of the SH3 domain". Nat. Struct. Biol. 8 (6): 526–30. doi:10.1038/88591. PMID 11373621.
  4. ^ Karathanassis D, Stahelin RV, Bravo J, Perisic O, Pacold CM, Cho W, Williams RL (October 2002). "Binding of the PX domain of p47phox to phosphatidylinositol 3,4-bisphosphate and phosphatidic acid is masked by an intramolecular interaction". EMBO J. 21 (19): 5057–68. doi:10.1093/emboj/cdf519. PMC 129041. PMID 12356722.
  5. ^ Ago T, Kuribayashi F, Hiroaki H, Takeya R, Ito T, Kohda D, Sumimoto H (April 2003). "Phosphorylation of p47phox directs phox homology domain from SH3 domain toward phosphoinositides, leading to phagocyte NADPH oxidase activation". Proc. Natl. Acad. Sci. U.S.A. 100 (8): 4474–9. doi:10.1073/pnas.0735712100. PMC 153580. PMID 12672956.