Fig. 2

Signaling pathways for CSF-1 and FAK. CSF-1R predominantly modulates differentiation, proliferation and survival via PI3K or the RAF/MEK/ERK pathway. For the regulation of cell adhesion and migration, the binding of CSF-1 to CSF-1R leads to phosphorylation of FAK, which in turn activates numerous signaling pathways that lead to actin polymerization/cytoskeleton remodeling, adhesion dynamics and migration (via ERK, N-WASP/CDC42, VCAM and Selectin). However, like CSF-1/CSF-1R, FAK is also involved in cell survival via the PI3/AKT pathway. Interaction of ECM protein (e.g. fibronectin) with integrins can also activate FAK, which leads to ligand-independent phosphorylation of CSF-1R, and thus cell migration (inset on left lower portion of Fig. 1)