Arfaptin homology (AH) domain/BAR domain (IPR027267)

Short name: AH/BAR-dom

Domain relationships


This entry represents a domain consists of three alpha-helices, including the arfaptin homology (AH) domain and the BAR (Bin-Amphiphysin-Rvs)-domain.

The arfaptin homology (AH) domain is a protein domain found in a range of proteins, including arfaptins, protein kinase C-binding protein PICK1 [PMID: 10623590] and mammalian 69 kDa islet cell autoantigen (ICA69) [PMID: 12682071]. The AH domain of arfaptin has been shown to dimerise and to bind Arf and Rho family GTPases [PMID: 11346801, PMID: 11696355], including ARF1, a small GTPase involved in vesicle budding at the Golgi complex and immature secretory granules. The AH domain consists of three alpha-helices arranged as an extended antiparallel alpha-helical bundle. Two arfaptin AH domains associate to form a highly elongated, crescent-shaped dimer [PMID: 11346801, PMID: 11696355].

Members of the Amphiphysin protein family are key regulators in the early steps of endocytosis, involved in the formation of clathrin-coated vesicles by promoting the assembly of a protein complex at the plasma membrane and directly assist in the induction of the high curvature of the membrane at the neck of the vesicle. Amphiphysins contain a characteristic domain, known as the BAR (Bin-Amphiphysin-Rvs)-domain, which is required for their in vivo function and their ability to tubulate membranes [PMID: 14993925]. The crystal structure of these proteins suggest the domain forms a crescent-shaped dimer of a three-helix coiled coil with a characteristic set of conserved hydrophobic, aromatic and hydrophilic amino acids. Proteins containing this domain have been shown to homodimerise, heterodimerise or, in a few cases, interact with small GTPases.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.