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Regulation of mitochondrial morphology and inheritance by Mdm10p, a protein of the mitochondrial outer membrane
1Department of Biology, University of California, San Diego, La Jolla 92093-0347.
Abstract:
Yeast cells with the mdm10 mutation possess giant spherical mitochondria and are defective for mitochondrial inheritance. The giant mitochondria display classical features of mitochondrial ultrastructure, yet they appear incapable of movement or division. Genetic analysis indicated that the mutant phenotypes resulted from a single nuclear mutation, and the isolated MDM10 gene restored wild-type mitochondrial distribution and morphology when introduced into mutant cells. MDM10 encodes a protein of 56.2 kD located in the mitochondrial outer membrane. Depletion of Mdm10p from cells led to a condensation of normally extended, tubular mitochondria into giant spheres, and reexpression of the protein resulted in a rapid restoration of normal mitochondrial morphology. These results demonstrate that Mdm10p can control mitochondrial morphology, and that it plays a role in the inheritance of mitochondria.
Insights
The MDM10 gene controls yeast mitochondrial shape and inheritance. Mutations cause giant mitochondria, but restoring MDM10 fixes mitochondrial morphology and distribution.
Area of Science:
- Cell Biology
- Genetics
- Mitochondrial Biology
Background:
- Yeast cells with mdm10 mutations exhibit abnormal mitochondrial morphology, appearing as giant spheres.
- These mutant cells are also defective in the proper inheritance of mitochondria.
Purpose of the Study:
- To investigate the function of the MDM10 gene in yeast.
- To understand the role of the Mdm10 protein in regulating mitochondrial morphology and inheritance.
Main Methods:
- Genetic analysis of yeast mutants.
- Gene isolation and reintroduction of the MDM10 gene.
- Microscopy to observe mitochondrial ultrastructure and distribution.
Main Results:
- The mdm10 mutation leads to giant, spherical mitochondria that are unable to move or divide.
- The MDM10 gene, encoding a 56.2 kD protein in the mitochondrial outer membrane, restored normal mitochondrial morphology and distribution when reintroduced.
- Depletion of Mdm10p caused tubular mitochondria to condense into giant spheres, while its reexpression rapidly restored normal morphology.
Conclusions:
- Mdm10p is crucial for controlling mitochondrial morphology in yeast.
- Mdm10p plays a significant role in the inheritance of mitochondria.