Inverse (I)-BAR, also known as the IRSp53/MIM homology Domain (IMD), of Brain-specific Angiogenesis Inhibitor 1-Associated Protein 2-Like 1
The IMD domain, also called Inverse-Bin/Amphiphysin/Rvs (I-BAR) domain, is a dimerization and lipid-binding module that bends membranes and induces membrane protrusions. BAIAP2L1 (Brain-specific Angiogenesis Inhibitor 1-Associated Protein 2-Like 1) is also known as IRTKS (Insulin Receptor Tyrosine Kinase Substrate). It is widely expressed, serves as a substrate for the insulin receptor, and binds the small GTPase Rac. It plays a role in regulating the actin cytoskeleton and colocalizes with F-actin, cortactin, VASP, and vinculin. BAIAP2L1 expression leads to the formation of short actin bundles, distinct from filopodia-like protrusions induced by the expression of the related protein IRSp53. It contains an N-terminal IMD, an SH3 domain, and a WASP homology 2 (WH2) actin-binding motif at the C-terminus. The IMD domain of BAIAP2L1 binds and bundles actin filaments, and binds the small GTPase Rac.