Binds to membranes enriched in phosphatidylinositol 3-phosphate (PtdIns(P3)) and phosphatidylinositol 4,5-bisphosphate (PubMed:25882846). May be involved in several stages of intracellular trafficking. Monomer. The PX domain mediates specific binding to membranes enriched in phosphatidylinositol 3-phosphate (PtdIns(P3)). Belongs to the sorting nexin family.