The Bin/Amphiphysin/Rvs (BAR) domain of yeast Sorting Nexin Vps17p
BAR domains are dimerization, lipid binding and curvature sensing modules found in many different proteins with diverse functions. Sorting nexins (SNXs) are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNXs differ from each other in their lipid-binding specificity, subcellular localization and specific function in the endocytic pathway. A subset of SNXs also contain BAR domains. The PX-BAR structural unit determines the specific membrane targeting of SNXs. Vsp17p forms a dimer with Vps5p, the yeast counterpart of human SNX1, and is part of the retromer complex that mediates the transport of the carboxypeptidase Y receptor Vps10p from endosomes to Golgi. BAR domains form dimers that bind to membranes, induce membrane bending and curvature, and may also be involved in protein-protein interactions.