Focal Adhesion Kinase - FAK ( focal adhesion kinase) belongs to the group of non-receptor protein tyrosine kinases . It occurs in the cytoplasm of most cells , including osteoblasts. At the time of its activation , the interaction of integrin associated protein extracellular matrix call is incorporated into platelet adhesion . FAK kinase in the presence of these structures is closely related to a function that plays in cellular processes such as adhesion, migration, proliferation . FAK -deficient cells show a much slower growth and reduced mobility. Kinase activates a variety of signal transduction pathways in the cell, leading inter alia to cell differentiation . By controlling the activity of kinases belonging to the group of MAPK ( mitogen -activated protein kinase ) , influences the maturation and differentiation of cells into the osteoblasts in vitro. Indirectly stimulates the activation of genes characteristic of the osteoblast phenotype valid : Runx2 and Osterix . None of the gene encoding a protein prevents the cell differentiation towards osteoblastycznym . In this paper seeks to demonstrate the role the kinase FAK in cell biology , with particular emphasis on osteoblasts.