Dynamin regulates the dynamics and mechanical strength of the actin cytoskeleton as a multifilament actin-bundling protein

Nat Cell Biol. 2020 Jun;22(6):674-688. doi: 10.1038/s41556-020-0519-7. Epub 2020 May 25.


The dynamin GTPase is known to bundle actin filaments, but the underlying molecular mechanism and physiological relevance remain unclear. Our genetic analyses revealed a function of dynamin in propelling invasive membrane protrusions during myoblast fusion in vivo. Using biochemistry, total internal reflection fluorescence microscopy, electron microscopy and cryo-electron tomography, we show that dynamin bundles actin while forming a helical structure. At its full capacity, each dynamin helix captures 12-16 actin filaments on the outer rim of the helix. GTP hydrolysis by dynamin triggers disassembly of fully assembled dynamin helices, releasing free dynamin dimers/tetramers and facilitating Arp2/3-mediated branched actin polymerization. The assembly/disassembly cycles of dynamin promote continuous actin bundling to generate mechanically stiff actin super-bundles. Super-resolution and immunogold platinum replica electron microscopy revealed dynamin along actin bundles at the fusogenic synapse. These findings implicate dynamin as a unique multifilament actin-bundling protein that regulates the dynamics and mechanical strength of the actin cytoskeletal network.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actin-Related Protein 2-3 Complex / metabolism
  • Actins / genetics
  • Actins / metabolism*
  • Amino Acid Sequence
  • Animals
  • Cell Communication*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism*
  • Dynamins / genetics
  • Dynamins / metabolism*
  • Endocytosis*
  • Female
  • Guanosine Triphosphate / metabolism
  • Male
  • Myoblasts / cytology
  • Myoblasts / metabolism
  • Protein Binding
  • Sequence Homology


  • Actin-Related Protein 2-3 Complex
  • Actins
  • Guanosine Triphosphate
  • Dynamins