Catastrophic actin filament bursting by cofilin, Aip1, and coronin

Vivian W. Tang, Ambika V. Nadkarni, William M. Brieher

Research output: Contribution to journalArticlepeer-review

Abstract

Cofilin is an actin filament severing protein necessary for fast actin turnover dynamics. Coronin and Aip1 promote cofilin-mediated actin filament disassembly, but the mechanism is somewhat controversial. An early model proposed that the combination of cofilin, coronin, and Aip1 disassembled filaments in bursts. A subsequent study only reported severing. Here, we used EM to show that actin filaments convert directly into globular material. A monomer trap assay also shows that the combination of all three factors produces actin monomers faster than any two factors alone. We show that coronin accelerates the release of Pi from actin filaments and promotes highly cooperative cofilin binding to actin to create long stretches of polymer with a hypertwisted morphology. Aip1 attacks these hypertwisted regions along their sides, disintegrating them into monomers or short oligomers. The results are consistent with a catastrophic mode of disassembly, not enhanced severing alone.

Original languageEnglish (US)
Pages (from-to)13299-13313
Number of pages15
JournalJournal of Biological Chemistry
Volume295
Issue number38
DOIs
StatePublished - Sep 18 2020

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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