New Model for Stacking Monomers in Filamentous Actin from Skeletal Muscles of Oryctolagus cuniculus

Int J Mol Sci. 2020 Nov 6;21(21):8319. doi: 10.3390/ijms21218319.


To date, some scientific evidence (limited proteolysis, mass spectrometry analysis, electron microscopy (EM)) has accumulated, which indicates that the generally accepted model of double-stranded of filamentous actin (F-actin) organization in eukaryotic cells is not the only one. This entails an ambiguous understanding of many of the key cellular processes in which F-actin is involved. For a detailed understanding of the mechanism of F-actin assembly and actin interaction with its partners, it is necessary to take into account the polymorphism of the structural organization of F-actin at the molecular level. Using electron microscopy, limited proteolysis, mass spectrometry, X-ray diffraction, and structural modeling we demonstrated that F-actin presented in the EM images has no double-stranded organization, the regions of protease resistance are accessible for action of proteases in F-actin models. Based on all data, a new spatial model of filamentous actin is proposed, and the F-actin polymorphism is discussed.

Keywords: accessible surface area; actin; electron microscopy; filament; mass spectrometry; monomer; proteolysis.

MeSH terms

  • Actin Cytoskeleton / chemistry
  • Actins / chemistry
  • Actins / metabolism*
  • Actins / ultrastructure*
  • Animals
  • Microscopy, Electron / methods
  • Models, Molecular
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / physiology*
  • Rabbits / metabolism
  • X-Ray Diffraction / methods


  • Actins