SPRY1 is a 34-38kD member of the sprouty family of proteins. It is widely expressed, being found in multiple embryonic and adult tissues. SPRY1 is considered a negative regulator of cellular signaling. In particular, it appears to both inhibit MAP kinase signaling following RTK activation, and block TCR signaling following antigen activation. It interacts with a number of molecules, including PLC-g 1, LAT, CBL, caveolin-1 and SPRY2. Human SPRY1 is 319aa in length. It contains one CBL-TKB binding site aa51-57 that is phosphorylated at Tyr53, a Ser-rich region aa112-131, and a Cys-rich domain aa181-306 that mediates intracellular translocation. SPRY1 undergoes serine phosphorylation, ubiquitination and palmitoylation, the latter which induces SPRY1 to associate with cell membranes. Over aa1-178, human SPRY1 shares 76% aa identity with mouse SPRY1.