This entry includes sorting nexins SNX20 and SNX21. They are sorting nexins (SNX) that orchestrate membrane trafficking and signaling events required for the proper distribution of proteins within the endosomal network. They contain an N-terminal PX domain and a C-terminal PX-associated B (PXB) domain. Their structures have been determined []. SNX20 has been shown to direct subcellular distribution of PSGL-1, a mucin-like glycoprotein []. SNX21 has been shown to serve as a scaffold for the endosomal recruitment of huntingtin [].