Regulation of focal complex composition and disassembly by the calcium-dependent protease calpain

J Cell Sci. 2002 Sep 1;115(Pt 17):3415-25. doi: 10.1242/jcs.115.17.3415.

Abstract

Cell migration requires the regulated and dynamic turnover of adhesive complexes. We have previously demonstrated that the calcium-dependent protease, calpain, regulates the organization of adhesive complexes and cell detachment during cell migration. Evidence is now provided that inhibiting calpain through over-expression of the endogenous inhibitor of calpain, calpastatin, and pharmacological inhibitors results in an inhibition of adhesive complex disassembly with stabilization of GFP-vinculin and GFP/RFP-zyxin at the cell periphery. Calpain was also required for the microtubule-mediated turnover of adhesive complex sites after nocodazole wash-out, suggesting that calpain may mediate focal complex disassembly downstream of microtubules. Using dual imaging of RFP-zyxin and GFP-alpha-actinin, we observed a temporal and spatial relationship between alpha-actinin localization to focal contacts and the subsequent disassembly or translocation of RFP-zyxin containing focal complexes in areas of cell retraction. Calpain inhibition disrupted alpha-actinin localization to zyxin-containing focal contacts and focal complex disassembly or translocation to the cell center. In addition, disrupting alpha-actinin localization to focal complexes through expression of the alpha-actinin rod domain, but not the head domain, resulted in inhibition of focal adhesion disassembly similar to calpain inhibition. Our studies suggest a novel mechanism of action whereby calpain may modulate alpha-actinin localization into focal complexes and their subsequent disassembly or translocation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actinin / genetics
  • Actinin / metabolism
  • Animals
  • CHO Cells
  • Calcium / metabolism*
  • Calcium-Binding Proteins / metabolism
  • Calpain / antagonists & inhibitors
  • Calpain / metabolism*
  • Cell Adhesion / physiology
  • Cell Movement / physiology*
  • Cells, Cultured
  • Cricetinae
  • Cysteine Proteinase Inhibitors / metabolism
  • Cytoskeletal Proteins
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Focal Adhesions / metabolism*
  • Glycoproteins
  • Goldfish
  • Green Fluorescent Proteins
  • Humans
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Metalloproteins / genetics
  • Metalloproteins / metabolism
  • Microscopy, Video
  • Microtubules / metabolism
  • Nocodazole / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism*
  • Red Fluorescent Protein
  • Vinculin / genetics
  • Vinculin / metabolism
  • Zyxin

Substances

  • Calcium-Binding Proteins
  • Cysteine Proteinase Inhibitors
  • Cytoskeletal Proteins
  • Glycoproteins
  • Luminescent Proteins
  • Metalloproteins
  • Recombinant Fusion Proteins
  • ZYX protein, human
  • Zyxin
  • Actinin
  • Vinculin
  • Green Fluorescent Proteins
  • calpastatin
  • Calpain
  • Nocodazole
  • Calcium