In 1992, Kumar, et al., first described a sequence tag corresponding to the NEDD9 3′ untranslated region based on the cloning of a group of genes predominantly expressed in the brain of embryonic, but not adult mice, a group of genes designated neural precursor cell expressed, developmentally down-regulated.[2] In 1996, two groups independently described the complete sequence of the NEDD9 gene, and provided initial functional analysis of NEDD9 protein. Law et al. overexpressed a human cDNA library in S. cerevisiae, and screened for genes that simultaneously affected cell cycle and cell polarity controls, inducing a filamentous yeast budding phenotype, and thus identified the HEF1 protein (Human Enhancer of Filamentation 1).[3] This study identified HEF1/NEDD9 as an interactive partner for focal adhesion kinase (FAK), connecting it to integrin signaling. Separately, Minegishi et al. cloned the gene encoding a protein hyperphosphorylated following ligation of β1-integrins in T cells and hypothesized to play a role in the process of T cell costimulation, designating this gene Cas-L (Crk-associated substrate-related protein, Lymphocyte type).[4]