NCK1 is one of the adaptor proteins which mediate specific protein-protein interactions in signaling processes. Adaptor proteins usually contain several domains like SH2 (Src homology 2) and SH3 which allow specific interactions with other specific proteins. NCK1 and NCK2 showing high sequence identity (68%) have three SH3 domains and a C-terminal SH2 domain. Both of them bind receptor tyrosine kinases such as PDGFR and other tyrosine phosphorylated proteins via their SH2 domains. Various molecules which interact with SH domains of Nck and regulate signaling process of actin cytoskeleton reorganization have been identified. Ncks are thought to have important functions in the development of mesodermal structures during embryogenesis, linked to a role in cell movement and cytoskeletal reorganization. Nck also have a function in modulating mRNA translation at the level of initiation by interacting eukayotic initiation factor 2 (eIF2). Under the stressed conditions, protein synthesis is reduced by inhibiting the activity of eIF2 through the phosphorylation, transiently inhibiting recycling of eIF2 into its active form. Adapter protein which associates with tyrosine-phosphorylated growth factor receptors or their cellular substrates. Maintains low levels of EIF2S1 phosphorylation by promoting its dephosphorylation by PP1. Plays a role in the DNA damage response, not in the detection of the damage by ATM/ATR, but for efficient activation of downstream effectors, such as that of CHEK2.