| Primary Identifier | IPR042133 | Type | Domain |
| Short Name | PX_PI3K_C2_alpha |
| description | This entry represents the PX domain found in phosphatidylinositol 4-phosphate 3-kinase C2 domain-containing subunit alpha (PI3K-C2alpha). The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others []. PI3K-C2alpha, the class II alpha isoform of PI3K, plays key roles in clathrin assembly and clathrin-mediated membrane trafficking, insulin signaling, vascular smooth muscle contraction, and the priming of neurosecretory granule exocytosis [, , ]. The PX domain is involved in targeting of proteins to PI-enriched membranes, and may also be involved in protein-protein interaction [, ].The Phosphoinositide 3-Kinase (PI3K) family of enzymes catalyzes the phosphorylation of the 3-hydroxyl group of the inositol ring of phosphatidylinositol. PI3Ks play an important role in a variety of fundamental cellular processes, including cell motility, the Ras pathway, vesicle trafficking and secretion, immune cell activation and apoptosis [, ]. PI3Ks are divided into three main classes (I, II, and III) based on their substrate specificity, regulation, and domain structure. Class II PI3Ks preferentially use PI as a substrate to produce PI3P, but can also phosphorylate PI4P to produce PI(3,4)P2. They function as monomers and do not associate with any regulatory subunits. Class II enzymes contain an N-terminal Ras binding domain, a lipid binding C2 domain, a PI3K homology domain of unknown function, an ATP-binding cataytic domain, a PX domain, and a second C2 domain at the C terminus []. |
