Phosphorylated tyrosine Y397 in the FERM domain of PTK2 (FAK1), along with an adjacent proline-rich motif, creates a docking site for the SRC kinase (Schaller et al. 1994, Xing et al. 1994, Thomas et al. 1998). It has not been specifically tested in this context whether PTK2 promotes SRC activation, and SRC is therefore represented in its active form.