C-terminal FAT-like Four helix bundle domain, also called DUF3513, of CAS (Crk-Associated Substrate) scaffolding protein, Neural precursor cell Expressed, Developmentally Down-regulated 9; a protein interaction module
NEDD9 is also called human enhancer of filamentation 1 (HEF1) or CAS-L (Crk-associated substrate in lymphocyte). It was first described as a gene predominantly expressed in early embryonic brain, and was also isolated from a screen of human proteins that regulate filamentous budding in yeast, and as a tyrosine phosphorylated protein in lymphocytes. It promotes metastasis in different solid tumors. NEDD9 localizes in focal adhesions and associates with FAK and Abl kinase. It also interacts with SMAD3 and the proteasomal machinery which allows its rapid turnover; these interactions are not shared by other CAS proteins. CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes. They share a common domain structure containing protein interaction modules that enable their scaffolding function, including an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain, which binds to the C-terminal domain of NSPs (novel SH2-containing proteins) to form multidomain signaling modules that mediate cell migration and invasion.