Inverse (I)-BAR, also known as the IRSp53/MIM homology Domain (IMD), of Missing In Metastasis
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. Members of this subfamily include missing in metastasis (MIM) or metastasis suppressor 1 (MTSS1), metastasis suppressor 1-like (MTSSL) or ABBA (Actin-Bundling protein with BAIAP2 homology), and similar proteins. They contain an N-terminal IMD and a WASP homology 2 (WH2) actin-binding motif at the C-terminus. MIM was originally identified as a missing transcript from metastatic bladder and prostate cancer cells. It is a scaffold protein that functions in a signaling pathway between the PDGF receptor, Src kinases, and actin assembly. It may also function as a cofactor of the Sonic hedgehog (Shh) transcriptional pathway and may participate in tumor development and progression via this pathway. ABBA regulates actin and plasma membrane dynamics to promote the extension of radial glia, which is important in neuronal migration, axon guidance and neurogenesis. The IMD domain of MIM binds and bundles actin filaments, binds membranes, and interacts with the small GTPase Rac.