BAR domain

BAR (Bin–Amphiphysin–Rvs) domains are highly conserved protein dimerisation domains that occur in many proteins involved in membrane dynamics in a cell. The BAR domain is banana shaped and binds to membrane via its concave face. It is capable of sensing membrane curvature by binding preferentially to curved membranes.

BAR domains occur in combinations with other domains

Many BAR family proteins contain alternative lipid specificity domains that help target these protein to particular membrane compartments. Some also have SH3 domains that bind to dynamin and thus proteins like amphiphysin and endophilin are implicated in the orchestration of vesicle scission.

N-BAR domain

Some BAR domain containing proteins have an N-terminal amphipathic helix preceding the BAR domain. This helix inserts (like in the epsin ENTH domain) into the membrane and induces curvature, which is stabilised by the BAR dimer. Amphiphysin, endophilin, BRAP1/bin2 and nadrin are examples of such proteins containing an N-BAR. The Drosophila amphiphysin N-BAR (DA-N-BAR) is an example of a protein with a preference for negatively charged surfaces.