I-BAR domain containing protein IRSp53 (IPR030128)

Short name: IRSp53

Overlapping homologous superfamilies


Family relationships


IRSp53, also known as IRS-58 or BAIAP2 (brain-specific angiogenesis inhibitor 1-associated protein 2), is an I-BAR (Bin/amphipysin/Rvs) domain containing protein. BAR domain forms an anti-parallel all-helical dimer, with a curved (banana-like) shape, that promotes membrane tubulation. BAR domain proteins can be classified into three types: BAR, F-BAR and I-BAR. BAR and F-BAR proteins generate positive membrane curvature, while I-BAR proteins induce negative curvature [PMID: 21743456].

IRSp53 is an adaptor protein that acts at the membrane-actin interface, coupling membrane deformation with F-actin polymerisation [PMID: 23740402]. It is involved in the formation of filopodia and lamellipodia in cultured mesenchymal cells and contributes to assembly/maintenance of tight junctions in cultured epithelial cells [PMID: 21093245]. IRSp53 contains an N-terminal I-BAR domain, followed by a partial CRIB domain and a SH3 domain. It binds to small GTPase Cdc42, Rac1 and WAVE1 [PMID: 19913105]. IRSp53 binds Rac through its I-BAR domain and to WAVE through its SH3 domain, and thus contributes to membrane ruffling [PMID: 11696321]. Its SH3 domain also interacts with other regulators of actin dynamics, such as WAVE2, Mena, mDia1, Dynamin1, Eps8 and N-WASP [PMID: 21093245].

GO terms

Biological Process

GO:0032956 regulation of actin cytoskeleton organization

Molecular Function

GO:0008093 cytoskeletal adaptor activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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