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Crystal structure of mitochondrial fission complex reveals scaffolding function for mitochondrial division 1 (Mdv1)

Yan Zhang1, Nickie C Chan2, Huu B Ngo1

  • 1Division of Biology, California Institute of Technology, Pasadena, California 91125.

The Journal of Biological Chemistry
|February 4, 2012
PubMed

Insights

Mitochondrial fission involves Fis1, Mdv1, and Dnm1 proteins. The Mdv1 adaptor protein

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Mitochondrial fission is crucial for cellular health and is mediated by specific protein machinery.
  • In yeast, Fis1, Mdv1, and Dnm1 are key components of the mitochondrial fission process.
  • Mdv1 acts as a molecular adaptor, linking Fis1 and Dnm1.

Purpose of the Study:

  • To elucidate the structural basis of the Mdv1-Fis1 complex formation.
  • To understand the role of Mdv1's coiled-coil region in mitochondrial fission.
  • To investigate the functional significance of novel contacts within the Mdv1-Fis1 complex.

Main Methods:

  • X-ray crystallography was used to determine the structure of the dimeric Mdv1-Fis1 complex.
  • Mutational analyses were performed to assess the importance of specific protein contacts.
  • Biochemical assays were likely employed to evaluate mitochondrial fission activity.

Main Results:

  • The crystal structure revealed a compact and rigid Mdv1-Fis1 complex.
  • Mdv1 binds Fis1 via a helix-loop-helix motif, and dimerization occurs through its coiled coil.
  • Two additional contacts involving the Mdv1 coiled coil stabilize the complex and are crucial for fission.
  • The Mdv1 coiled coil functions as a scaffold, stabilizing the Mdv1-Fis1 interaction.

Conclusions:

  • The Mdv1 coiled coil plays a dual role in dimerization and scaffolding within the mitochondrial fission machinery.
  • Novel contacts mediated by the Mdv1 coiled coil are essential for efficient mitochondrial fission.
  • Structural insights into the Mdv1-Fis1 complex provide a deeper understanding of mitochondrial dynamics.

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