Probable catalytically inactive kinase. Scaffolding protein that regulates the cytoskeleton to control cell spreading and migration by modulating focal adhesion dynamics. Acts as a scaffold for mediating EGFR signaling. Homodimer (By similarity). Interacts with BCAR1 and CRK (By similarity). Interacts with PRAG1 (By similarity). Interacts (when phosphorylated at Tyr-1177) with SHC1 (via PID domain) (By similarity). Found in a complex with PPP1CA, PPP1CC and SHC1 (By similarity). Colocalizes with actin (PubMed:20534451). The dimerization region encompasses helices both from the N- and C-terminal of the protein kinase domain. Phosphorylated on tyrosine in a CSK-dependent manner in response to adhesion to fibronectin and to EGF stimulation (PubMed:20534451). Phosphorylation at Tyr-662 by a Src family kinase controls subcellular localization to focal adhesion and focal adhesion dynamics. Phosphorylation at Tyr-1177 is essential for binding to SHC1. Belongs to the protein kinase superfamily. Has been the subject of controversy surrounding its catalytic capabilities. Early characterization of PEAK1 gave a weak in vitro tyrosine kinase activity. The crystal structure indicates that the kinase-domain contains a closed nucleotide-binding cleft that in this conformation may deleteriously affect nucleotide bindin. Furthermore PEAK1 is devoid of nucleotide binding activity, as detected by a thermal-shift assay. So it seems probable that PEAK1 is an inactive kinase.