Probable catalytically inactive kinase (Probable). Interacts with CRK-II and antagonizes CRK-II-signaling. Prevents the formation of CRK-II-dependent membrane ruffling and lamellipodia-like extensions (PubMed:31311869). Homodimerizes (PubMed:31311869). Interacts with CRK isoform CRK-II; the interaction requires PEAK3 homodimerization (PubMed:31311869). Belongs to the protein kinase superfamily.