Yeast mitochondrial division and distribution require the cortical num1 protein

Dev Cell. 2007 Mar;12(3):363-75. doi: 10.1016/j.devcel.2007.01.017.


Yeast mitochondrial division requires the dynamin-related Dnm1 protein. By isolating high-copy suppressors of a dominant-negative Dnm1p mutant, we uncovered an unexpected role in mitochondrial division and inheritance for Num1p, a protein previously shown to facilitate nuclear migration. num1 mutants contain an interconnected network of mitochondrial tubules, remarkably similar to cells lacking Dnm1p, and time-lapse microscopy confirms that mitochondrial fission is greatly reduced in num1Delta cells. We also find that Num1p assembles into punctate structures, which often colocalize with mitochondrial-bound Dnm1p particles. Suggesting a role for both Num1p and Dnm1p in mitochondrial inheritance, we find that num1 dnm1 double mutants accumulate mitochondria in daughter buds and that mother cells are frequently devoid of all mitochondria. Thus, our studies have revealed an additional role for Dnm1p in mitochondrial transmission through its interaction with Num1p, thereby providing a link between mitochondrial division and inheritance.

Publication types

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

MeSH terms

  • Binding Sites / physiology
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism*
  • Cytokinesis / physiology*
  • Cytoplasm / metabolism
  • Cytoplasm / ultrastructure
  • Cytoskeletal Proteins
  • DNA, Mitochondrial / genetics
  • Extrachromosomal Inheritance / genetics*
  • GTP Phosphohydrolases / genetics
  • GTP Phosphohydrolases / metabolism*
  • Mitochondria / genetics
  • Mitochondria / metabolism*
  • Mitochondria / ultrastructure
  • Mitochondrial Membranes / metabolism
  • Mitochondrial Membranes / ultrastructure
  • Mitochondrial Proteins
  • Protein Transport / physiology
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae / ultrastructure
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*


  • Calcium-Binding Proteins
  • Cytoskeletal Proteins
  • DNA, Mitochondrial
  • Mitochondrial Proteins
  • NUM1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • GTP Phosphohydrolases
  • DNM1 protein, S cerevisiae