Domain

IMD/I-BAR domain (IPR013606)

Short name: I-BAR_dom

Domain relationships

None.

Description

The I-BAR domain (also known as IMD domain, IRSp53 and MIM homology domain) is a BAR-like domain of approximately 250 amino acids found at the N-terminal in the IRSp53 (insulin receptor tyrosine kinase substrate p53) and in the evolutionarily related IRSp53/MIM family. The BAR domain forms an anti-parallel all-helical dimer, with a curved (banana-like) shape, that promotes membrane tubulation. The BAR domain containing 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, PMID: 21093245]. The I-BAR domain containing proteins include:

  • Vertebrate MIM (missing in metastasis), an actin-binding scaffold protein that may be involved in cancer metastasis.
  • Vertebrate ABBA, a MIM-related protein.
  • Vertebrate insulin receptor tyrosine kinase substrate p53 (IRSp53), a multifunctional adaptor protein that links Rac1 with a Wiskott-Aldrich syndrome family verprolin-homologous protein 2 (WAVE2) to induce lamellipodia or Cdc42 with Mena to induce filopodia [PMID: 14980512].
  • Vertebrate IRTKS.
  • Vertebrate Pinkbar.
  • Drosophila melanogaster (Fruit fly) CG32082-PA.
  • Caenorhabditis elegans M04F3.5 protein.

The vertebrate I-BAR family is divided into two major groups: the IRSp53/IRTKS/Pinkbar subfamily and the MIM/ABBA subfamily. The putative invertebrate homologues are positioned between them. The IRSp53/IRTKS/Pinkbar subfamily members contain a SH3 domain, and the MIM/ABBA subfamily proteins contain a WH2 (WASP-homology 2) domain. The vertebrate SH3-containing subfamily is further divided into three groups according to the presence or absence of the WWB and the half-CRIB motif [PMID: 14752106, PMID: 17497115]. The BAR domain binds phosphoinositide-rich vesicles with high affinity and does not display strong actin filament binding/bundling activity [PMID: 21093245, PMID: 17371834].

GO terms

Biological Process

GO:0007009 plasma membrane organization

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

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