Identification of a functional switch for actin severing by cytoskeletal proteins. Academic Article uri icon


  • Actin severing is vital for the organization of the actin cytoskeleton during cell motility. Severing of F-actin by the homologous proteins villin and gelsolin requires unphysiologically high calcium concentrations (20-200 microM). Here we demonstrate that high calcium releases an autoinhibited conformation in villin that is maintained by two low affinity calcium binding sites (aspartic acids 467 and 715) that interact with a cluster of basic residues in the S2 domain of villin. Mutation of either of these sites as well as tyrosine phosphorylation alters the conformation of villin resulting in a protein that can sever actin in nanomolar calcium. These results suggest that tyrosine phosphorylation rather than high calcium may be the mechanism by which villin and other related proteins sever actin in vivo.

published proceedings

  • J Biol Chem

author list (cited authors)

  • Kumar, N., & Khurana, S

citation count

  • 38

complete list of authors

  • Kumar, Narendra||Khurana, Seema

publication date

  • April 2004