Fig. 5. Presence of PYK2/FAK chimeras in focal contacts rescues FN allocation. (A) Schematic diagram of Pyk2/FAK chimeras and properties of cell lines expressing them (Klingbeil et al., 2001). (B) Stable expression of the PYK2/FAK chimera in FAK^-/- cells either at a low level (CA3 cells) or at a high level (CB4 cells) was sufficient to rescue FN matrix allocation on the dorsal surface of confluent cells, as assessed with FN and ß₁-integrin staining. Mutation in the paxillin-binding domain of FAT (L1034S) prevents localization of chimeric PYK2/FAK protein in focal adhesion sites. Neither low levels (SE6 cells) nor high levels (SX4 cells) of stable L1034S PYK2/FAK chimera expression were sufficient to rescue the cells.