Evidence for multisite ligand binding and stretching of filamin by integrin and migfilin

Biochemistry. 2011 May 24;50(20):4229-31. doi: 10.1021/bi2003229. Epub 2011 Apr 27.

Abstract

Filamin, a large cytoskeletal adaptor, connects plasma membrane to cytoskeleton by binding to transmembrane receptor integrin and actin. Seven of 24 filamin immunoglobulin repeats have conserved integrin binding sites, of which repeats 19 and 21 were shown to be autoinhibited by their adjacent repeats 18 and 20, respectively. Here we show using nuclear magnetic resonance spectroscopy that the autoinhibition can be relieved by integrin or integrin regulator migfilin. We further demonstrate that repeats 19 and 21 can simultaneously engage ligands. The data suggest that filamin is mechanically stretched by integrin or migfilin via a multisite binding mechanism for regulating cytoskeleton and integrin-mediated cell adhesion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calorimetry
  • Contractile Proteins / metabolism*
  • Cytoskeletal Proteins / metabolism*
  • Filamins
  • Humans
  • Integrins / metabolism*
  • Ligands
  • Microfilament Proteins / metabolism*
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Binding

Substances

  • Contractile Proteins
  • Cytoskeletal Proteins
  • Filamins
  • Integrins
  • Ligands
  • Microfilament Proteins