FRK (RAK), a SRC family member kinase, binds PTEN. The interaction involves the SH3 domain of FRK and the C2 domain of PTEN (Yim et al. 2009). Like other SRC family members, FRK is autophosphorylated on a C-terminal tyrosine residue Y387. FRK possesses a nuclear localization signal and is found in both nucleus and the cytosol (Cance et al. 1994).