Plays a role in vesicular protein sorting. Acts at the crossroads between the secretory and endocytic pathways. Is involved in the endosome to vacuole protein transport via its interaction with the BLOS1/2 proteins and, as component of the membrane-associated retromer complex, is also involved in endosome-to-Golgi retrograde transport. Required for the auxin-carrier protein PIN2 sorting to the lytic vacuolar pathway and the trafficking of several plasma membrane proteins. Also involved in the efficient sorting of seed storage protein globulin 12S. Homodimer. Heterodimer with SNX2A or SNX2B. Component of the retromer complex which consists of VPS29 (MAG1), VPS26 (VPS26A or VPS26B), VPS35 (VPS35A or VPS35B or VPS35C), VPS5/17 (SNX1 or SNX2A or SNX2B). Interacts with BLOS1 and BLOS2. Ubiquitously expressed. The PX domain binds phosphatidylinositol 3-phosphate which is necessary for peripheral membrane localization. Shorter primary roots, fewer secondary roots and an altered root gravitropic response. Accumulation of storage protein globulin 12S in dry seeds. Belongs to the sorting nexin family.