PX domain

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

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

The PX domain is structurally conserved in eukaryotes, although amino acid sequenves show little similarity. PX domains interact primarily with PtdIns(3)P lipids. 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

A-388D4.1; C20orf161; C20orf23; HS1BP3; NCF1; NCF1C; NCF4; NISCH; PIK3C2A; PIK3C2B; PIK3C2G; PLD1; PLD2; PXK; RPS6KC1; SGK3; SGKL; SH3PX3; SH3PXD2A; SLIC1; SNAG1; SNX1; SNX10; SNX11; SNX12; SNX13; SNX14; SNX15; SNX16; SNX17; SNX19; SNX2; SNX21; SNX22; SNX24; SNX25; SNX27; SNX3; SNX30; SNX4; SNX5; SNX6; SNX7; SNX8; SNX9;

References

• [1]. Novel domains in NADPH oxidase subunits, sorting nexins, and PtdIns 3-kinases: binding partners of SH3 domains? Ponting CP; Protein Sci 1996;5:2353-2357. PubMed
• [2]. Phoxy lipids: revealing PX domains as phosphoinositide binding modules. Wishart MJ, Taylor GS, Dixon JE; Cell 2001; 105:817-820. PubMed
• [3]. Binding of the PX domain of p47(phox) to phosphatidylinositol 3,4-bisphosphate and phosphatidic acid is masked by an intramolecular interaction. Karathanassis D, Stahelin RV, Bravo J, Perisic O, Pacold CM, Cho W, Williams RL; EMBO J 2002;21:5057-5068. PubMed
• [4]. Phosphorylation of p47phox directs phox homology domain from SH3 domain toward phosphoinositides, leading to phagocyte NADPH oxidase activation. Ago T, Kuribayashi F, Hiroaki H, Takeya R, Ito T, Kohda D, Sumimoto H; Proc Natl Acad Sci U S A 2003;100:4474-4479. PubMed
• [5]. Solution structure of the PX domain, a target of the SH3 domain. Hiroaki H, Ago T, Ito T, Sumimoto H, Kohda D; Nat Struct Biol 2001;8:526-530. PubMed