May play a role in cellular vesicle trafficking (PubMed:25882846). Has been proposed to function as a sorting protein that targets SELPLG into endosomes, but has no effect on SELPLG internalization from the cell surface, nor on SELPLG-mediated cell-cell adhesion (PubMed:18196517). Interacts with SELPLG (By similarity). Interaction with SELPLG is controversial and was not detected in PubMed:25882846. The PX domain binds phosphatidylinositol 3-phosphate which is necessary for localization to the endosomes. No visible phenotype. Mice appear healthy and normal. Neutrophils from mutant mice display unchanged Selplg-mediated cell-cell adhesion and Selplg expression at the cell membrane is unchanged. Belongs to the sorting nexin family.