Cyclin C directly stimulates Drp1 GTP affinity to mediate stress-induced mitochondrial hyperfission

Vidyaramanan Ganesan, Stephen D. Willis, Kai Ti Chang, Samuel Beluch, Katrina F. Cooper, Randy Strich

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Mitochondria exist in an equilibrium between fragmented and fused states that shifts heavily toward fission in response to cellular damage. Nuclear-to-cytoplasmic cyclin C relocalization is essential for dynamin-related protein 1 (Drp1)–dependent mitochondrial fission in response to oxidative stress. This study finds that cyclin C directly interacts with the Drp1 GTPase domain, increases its affinity to GTP, and stimulates GTPase activity in vitro. In addition, the cyclin C domain that binds Drp1 is contained within the non–Cdk binding second cyclin box domain common to all cyclin family members. This interaction is important, as this domain is sufficient to induce mitochondrial fission when expressed in mouse embryonic fibroblasts in the absence of additional stress signals. Using gel filtration chromatography and negative stain electron microscopy, we found that cyclin C interaction changes the geometry of Drp1 oligomers in vitro. High–molecular weight low–GTPase activity oligomers in the form of short filaments and rings were diminished, while dimers and elongated filaments were observed. Our results support a model in which cyclin C binding stimulates the reduction of low–GTPase activity Drp1 oligomers into dimers capable of producing high–GTPase activity filaments.

Original languageEnglish (US)
Pages (from-to)302-311
Number of pages10
JournalMolecular biology of the cell
Issue number3
StatePublished - Feb 1 2019

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology


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