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. The occurrence in different protein and more information can be found on endocytosis.org.
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.
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.
E-FCH domains (F-BARs) are BAR-like protein domains that are predicted extensions of the already established FCH domain. They are frequently found at the amino terminus of the protein. They can bind lipid membranes and can tubulate lipids in vitro, but their exact physiological role remains to be elucidated. Syndapin/pacsin proteins are an example of an F-BAR protein family.
- Peter, B.J., Kent, H.M., Mills, I.G., Vallis, Y., Butler, P.J.G., Evans, P.R. and McMahon, H.T. (2004) BAR Domains as Sensors of Membrane Curvature: the Amphiphysin BAR Structure. Science 303, 495-499. pubmed
- Weissenhorn W. (2005) Crystal structure of the endophilin-A1 BAR domain. J. Mol. Biol. 19, 185-196. pubmed
- Gallop, J.L., Jao, C.C., Kent, H.M., Butler, P.J.G., Evans, P.R., Langen, R. and McMahon, H.T. (2006) Mechanism of endophilin N-BAR domain-mediated membrane curvature. EMBO J. 25, 2898-2910. pubmed
- Masuda M, Takeda S, Sone M, Ohki T, Mori H, Kamioka Y, Mochizuki N. (2006) Endophilin BAR domain drives membrane curvature by two newly identified structure-based mechanisms. EMBO J. 25, 2889-2897. pubmed