Sorting nexin-9 is a protein that in humans is encoded by the SNX9 gene.

This gene encodes a member of the sorting nexin family. Members of this family contain a phox (PX) domain, which is a phosphoinositide binding domain, and are involved in intracellular trafficking. This protein does not contain a coiled coil region, like some family members, but does contain a SH3 domain near its N-terminus. This protein interacts with the cytoplasmic domains of the precursor but not the processed forms of a disintegrin and metalloprotease domain 9 and 15. This protein binds the beta-appendage domain of adaptor protein 2 and may function to assist adaptor protein 2 in its role at the plasma membrane. This protein interacts with activated Cdc42-associated kinase-2 to regulate the degradation of epidermal growth factor receptor protein. [provided by RefSeq, Jul 2008]. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Gene record to access additional publications.
Function: May be involved in several stages of intracellular trafficking. Plays a role in endocytosis via clathrin-coated pits, but also clathrin-independent, actin-dependent fluid-phase endocytosis. Plays a role in macropinocytosis. Promotes internalization of TNFR. Promotes degradation of EGFR after EGF signaling. Stimulates the GTPase activity of DNM1. Promotes DNM1 oligomerization. Promotes activation of the Arp2/3 complex by WASL, and thereby plays a role in the reorganization of the F-actin cytoskeleton. Binds to membranes enriched in phosphatidylinositol 4,5-bisphosphate and promotes membrane tubulation. Has lower affinity for membranes enriched in phosphatidylinositol 3-phosphate.