| We report here that Nck 2 interacts with focal adhesion kinase ( FAK ) , a cytoplasmic protein tyrosine kinase critically involved in the cellular control of motility . ^^^ Using a mutational strategy , we have found that the formation of the Nck 2 FAK complex is mediated by interactions involving multiple SH 2 and SH 3 domains of Nck 2 . ^^^ The Nck 2 SH 2 domain mediated interaction with FAK is dependent on phosphorylation of Tyr 397 , a site that is involved in the regulation of cell motility . ^^^ A fraction of Nck 2 co localizes with FAK at cell periphery in spreading cells . ^^^ These results identify a novel interaction between Nck 2 and FAK and suggest a role of Nck 2 in the modulation of cell motility . . ^^^ |