1y2o
From Proteopedia
Structure of N-terminal domain IRSp53/BAIAP2
Overview
The scaffolding protein insulin receptor tyrosine kinase substrate p53 (IRSp53), a ubiquitous regulator of the actin cytoskeleton, mediates filopodia formation under the control of Rho-family GTPases. IRSp53 comprises a central SH3 domain, which binds to proline-rich regions of a wide range of actin regulators, and a conserved N-terminal IRSp53/MIM homology domain (IMD) that harbours F-actin-bundling activity. Here, we present the crystal structure of this novel actin-bundling domain revealing a coiled-coil domain that self-associates into a 180 A-long zeppelin-shaped dimer. Sedimentation velocity experiments confirm the presence of a single molecular species of twice the molecular weight of the monomer in solution. Mutagenesis of conserved basic residues at the extreme ends of the dimer abrogated actin bundling in vitro and filopodia formation in vivo, demonstrating that IMD-mediated actin bundling is required for IRSp53-induced filopodia formation. This study promotes an expanded view of IRSp53 as an actin regulator that integrates scaffolding and effector functions.
About this Structure
1Y2O is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structural basis of filopodia formation induced by the IRSp53/MIM homology domain of human IRSp53., Millard TH, Bompard G, Heung MY, Dafforn TR, Scott DJ, Machesky LM, Futterer K, EMBO J. 2005 Jan 26;24(2):240-50. Epub 2005 Jan 6. PMID:15635447 Page seeded by OCA on Sat May 3 15:48:41 2008
