Sorting nexin (SNX) proteins are members of a large family of hydrophilic PX (phospholipid-binding motif) domain-containing proteins that interact with a variety of receptor types. SNXs are widely expressed, although the tissue distribution of each SNX mRNA varies. The ability of SNXs to bind specific phospholipids, as well as their tendency to form protein-protein complexes, suggests a role for these proteins in cellular membrane trafficking and protein sorting. SNXs may also function specifically in pro-degradative sorting, internalization, endosomal recycling or simply in endosomal sorting. SNX25 (sorting nexin 25), also known as SBBI31 or MSTP043, is an 840 amino acid protein suggested to function in several stages of intracellular trafficking. A member of the sorting nexin family, SNX25 contains one PX (phox homology) domain, an RGS domain and one PXA domain.