Probable catalytically inactive kinase. Scaffolding protein that regulates the cytoskeleton to control cell spreading and migration by modulating focal adhesion dynamics (PubMed:23105102, PubMed:20534451). Acts as a scaffold for mediating EGFR signaling (PubMed:23846654). Homodimer (PubMed:29212708). Interacts with BCAR1 and CRK (PubMed:20534451). Interacts with PRAG1 (PubMed:29079850). Interacts (when phosphorylated at Tyr-1188) with SHC1 (via PID domain) (PubMed:23846654). Found in a complex with PPP1CA, PPP1CC, SHC1 and PEAK1. Colocalizes with F-actin in serum-rich medium (PubMed:20534451). Actin colocalization is reduced during serum starvation (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-665 by a Src family kinase controls subcellular localization to focal adhesion and focal adhesion dynamics (PubMed:20534451). Phosphorylation at Tyr-1188 is essential for binding to SHC1 (PubMed:23846654). 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 (PubMed:20534451). The crystal structure indicates that the kinase-domain contains a closed nucleotide-binding cleft that in this conformation may deleteriously affect nucleotide binding (PubMed:29212708). Furthermore PEAK1 is devoid of nucleotide binding activity, as detected by a thermal-shift assay (PubMed:24107129). So it seems probable that PEAK1 is an inactive kinase.