2D1L: Structure Of F-actin Binding Domain Imd Of Mim (missing In Metastasis)

The adaptor protein missing-in-metastasis (MIM) contains independent F- and G-actin binding domains, consisting, respectively, of an N-terminal 250 aa IRSp53/MIM homology domain (IMD) and a C-terminal WASP-homology domain 2 (WH2). We determined the crystal structures of MIM's IMD and that of its WH2 bound to actin. The IMD forms a dimer, with each subunit folded as an antiparallel three-helix bundle. This fold is related to that of the BAR domain. Like the BAR domain, the IMD has been implicated in membrane binding. Yet, comparison of the structures reveals that the membrane binding surfaces of the two domains have opposite curvatures, which may determine the type of curvature of the interacting membrane. The WH2 of MIM is longer than the prototypical WH2, interacting with all four subdomains of actin. We characterize a similar WH2 at the C terminus of IRSp53 and propose that in these two proteins WH2 performs a scaffolding function.
PDB ID: 2D1LDownload
MMDB ID: 41393
PDB Deposition Date: 2005/8/27
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 1.85  Å
Source Organism:
Similar Structures:
Biological Unit for 2D1L: dimeric; determined by author and by software (PISA)
Molecular Components in 2D1L
Label Count Molecule
Proteins (2 molecules)
Metastasis Suppressor Protein 1(Gene symbol: Mtss1)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB