The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of Fes (feline sarcoma) tyrosine kinase
F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. Fes (feline sarcoma), also called Fps (Fujinami poultry sarcoma), is a cytoplasmic (or nonreceptor) tyrosine kinase whose gene was first isolated from tumor-causing retroviruses. It is expressed in myeloid, vascular endothelial, epithelial, and neuronal cells, and plays important roles in cell growth and differentiation, angiogenesis, inflammation and immunity, and cytoskeletal regulation. Fes kinase has also been implicated as a tumor suppressor in colorectal cancer. It contains an N-terminal F-BAR domain, an SH2 domain, and a C-terminal catalytic kinase domain. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules. The F-BAR domain of Fes is critical in its role in microtubule nucleation and bundling.