Adapter protein which associates with tyrosine-phosphorylated growth factor receptors, such as KDR and PDGFRB, 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. Plays a role in ELK1-dependent transcriptional activation in response to activated Ras signaling. Modulates the activation of EIF2AK2/PKR by dsRNA. May play a role in cell adhesion and migration through interaction with ephrin receptors. {ECO:0000269|PubMed:10026169, ECO:0000269|PubMed:16835242, ECO:0000269|PubMed:17803907, ECO:0000269|PubMed:18835251, ECO:0000269|PubMed:23358419, ECO:0000269|PubMed:9430661}. This is the function of ENSG00000158092 (NCK1, NCK adaptor protein 1).