Abstract: The present invention provides substantially purified members of the sorting nexin (SNX) family of proteins, which are involved in down regulating the expression of cell surface receptors and directing translocation of the receptor to a lysosome in the cell, as well as active fragments of an SNX and nucleic acid molecules encoding an SNX or an active fragment thereof. In addition, the invention provides nucleotide sequences that hybridize under relatively stringent conditions to a nucleic acid molecule encoding one or more members of the SNX family of proteins. The invention further provides vectors containing a nucleic acid molecule encoding a member of the SNX family of proteins or an active fragment thereof and provides host cells containing such vectors. The present invention further provides a method of modulating the expression of a cell surface receptor by expressing a nucleic acid molecule of the invention in a cell that can express the receptor.

Abstract: A novel protein that binds to the endocytic code of the human insulin receptor (hIR), which mediates receptor endocytosis, polynucleotides and methods of use are described.