The Bin/Amphiphysin/Rvs (BAR) domain of Adaptor protein, Phosphotyrosine interaction, PH domain and Leucine zipper containing 1
BAR domains are dimerization, lipid binding and curvature sensing modules found in many different proteins with diverse functions. Adaptor protein, Phosphotyrosine interaction, PH domain and Leucine zipper containing (APPL) proteins are effectors of the small GTPase Rab5 that function in endosome-mediated signaling. They contain BAR, pleckstrin homology (PH) and phosphotyrosine binding (PTB) domains. They form homo- and hetero-oligomers that are mediated by their BAR domains. Vertebrates contain two APPL proteins, APPL1 and APPL2. APPL1 interacts with diverse receptors (e.g. NGF receptor TrkA, FSHR, adiponectin receptors) and signaling proteins (e.g. Akt, PI3K), and may function as an adaptor linked to many distinct signaling pathways. BAR domains form dimers that bind to membranes, induce membrane bending and curvature, and may also be involved in protein-protein interactions.