The function of PEAK3 (PEAK family member 3, ENSG00000188305) is as follows. 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). {ECO:0000269|PubMed:31311869, ECO:0000305|PubMed:31311869}.