ADP-ribosylation of cross-linked actin generates barbed-end polymerization-deficient F-actin oligomers

Biochemistry. 2010 Oct 19;49(41):8944-54. doi: 10.1021/bi1008062.

Abstract

Actin filament subunit interfaces are required for the proper interaction between filamentous actin (F-actin) and actin binding proteins (ABPs). The production of small F-actin complexes mimicking such interfaces would be a significant advance toward understanding the atomic interactions between F-actin and its many binding partners. We produced actin lateral dimers and trimers derived from F-actin and rendered polymerization-deficient by ADP-ribosylation of Arg-177. The degree of modification resulted in a moderate reduction in thermal stability. Calculated hydrodynamic radii were comparable to theoretical values derived from recent models of F-actin. Filament capping capabilities were retained and yielded pointed-end dissociation constants similar those of wild-type actin, suggesting native or near-native interfaces on the oligomers. Changes in DNase I binding affinity under low and high ionic strength suggested a high degree of conformational flexibility in the dimer and trimer. Polymer nucleation activity was lost upon ADP-ribosylation and rescued upon enzyme-mediated deADP-ribosylation, or upon binding to gelsolin, suggesting that interactions with actin binding proteins can overcome the inhibiting activities of ADP-ribosylation. The combined strategy of chemical cross-linking and ADP-ribosylation provides a minimalistic and reversible approach to engineering polymerization-deficient F-actin oligomers that are able to act as F-actin binding protein scaffolds.

MeSH terms

  • Actin Cytoskeleton / chemistry
  • Actin Cytoskeleton / metabolism*
  • Actins / chemistry
  • Actins / metabolism*
  • Adenosine Diphosphate Ribose / chemistry
  • Adenosine Diphosphate Ribose / metabolism*
  • Animals
  • Cattle
  • Chickens
  • Deoxyribonuclease I / chemistry
  • Deoxyribonuclease I / metabolism
  • Gelsolin / chemistry
  • Gelsolin / metabolism
  • Humans
  • Protein Binding
  • Protein Multimerization / physiology*
  • Protein Structure, Quaternary

Substances

  • Actins
  • Gelsolin
  • Adenosine Diphosphate Ribose
  • Deoxyribonuclease I