| Type: | Domain | Name: | Phox homologous domain |
| Description: | The PX (phox) domain [] occurs in a variety of eukaryotic proteins and have been implicated in highly diverse functions such as cell signalling, vesicular trafficking, protein sorting and lipid modification [, , ]. PX domains are important phosphoinositide-binding modules that have varying lipid-binding specificities [].The PX domain is approximately 120 residues long [],and folds into a three-stranded beta-sheet followed by three -helices and a proline-rich region that immediately preceeds a membrane-interaction loop and spans approximately eight hydrophobic and polar residues. The PX domain of p47phox binds to the SH3 domain in the same protein[]. Phosphorylation of p47(phox), a cytoplasmic activator of the microbicidal phagocyte oxidase (phox), elicits interaction of p47(phox) with phoinositides. The protein phosphorylation-driven conformational change of p47(phox) enables its PX domain to bind to phosphoinositides, the interaction of which plays a crucial role in recruitment of p47(phox) from the cytoplasm to membranes and subsequent activation of the phagocyte oxidase. The lipid-binding activity of this protein is normally suppressed by intramolecular interaction of the PX domain with the C-terminal Src homology 3 (SH3) domain [].The PX domain is conserved from yeast to human. A recent multiple alignment of representative PX domain sequences can be found in [], although showing relatively little sequence conservation, their structure appears to be highly conserved. Although phosphatidylinositol-3-phosphate (PtdIns(3)P) is the primary target of PX domains, binding to phosphatidic acid, phosphatidylinositol-3,4-bisphosphate (PtdIns(3,4)P2), phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)P2), phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2), and phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3) has been reported as well. The PX-domain is also a protein-protein interaction domain []. | Short Name: | Phox |
| DB identifier | Type | Name |
|---|---|---|
| IPR016555 | Family | Phospholipase D1/D2 |
| IPR014536 | Family | Sorting nexin 9 subfamily |
| IPR014637 | Family | Sorting nexin-5/6/32 |
| IPR014461 | Family | Vacuolar protein sorting-associated protein 17, Vps17 |
| IPR000919 | Family | Neutrophil cytosol factor P40 |
| IPR001655 | Family | Neutrophil cytosol factor 1 |
