Gp300sca is Not a High Affinity Notch Ligand

The Notch protooncogene encodes a receptor important for determination and differentiation of many cell types, and is conserved between vertebrates and invertebrates. It has been suggested that the secreted protein scabrous (sca) might be a Notch ligand acting in the peripheral nervous system. The sca protein was purified and a cell line expressing 18,000 Notch molecules per cell surface used to test sca binding by coimmunoprecipitation, cell adhesion assays, and binding with labeled sca. No interaction was detected between gp300sca and Notch or the related protein Delta, suggesting that sca acts through a distinct mechanism.