NEDD9/CASL: Proteins and Enzymes

NEDD9 (also HEF1 and CASL) is a 93 kDa (predicted) member of the CAS family of proteins. It is widely expressed, and serves to integrate integrin beta 1 and BCR signaling with cell mitotic pathways. Human NEDD9 is 834 amino acids (aa) in length. It contains one SH3 domain (aa 3-65), a Tyr-rich SH2-binding region (aa 90-350), one Ser-rich four alpha-helix bundle protein interaction site (aa 350-650), and an HLH motif that mediates Cas protein dimerization (aa 710-760). NEDD9 usually runs at 105 or 115 kDa in SDS-PAGE due to phosphorylation. It is also cleaved near Leu361 to generate an active N-terminal 55 kDa fragment. One isoform shows a deletion of aa 155-188, while two others show 20 or 7 aa substitutions for aa 155-834 or 1-153, respectively. Over aa 153-366, human and mouse NEDD9 share 85% aa identity.