The cluA− mutant of Dictyostelium identifies a novel class of proteins required for dispersion of mitochondria
Abstract
The cluA gene of Dictyostelium discoideum encodes a novel 150-kDa protein. Disruption of cluA results in clustering of mitochondria near the cell center. This is a striking difference from normal cells, whose mitochondria are dispersed uniformly throughout the cytoplasm. The mutant cell populations also exhibit an increased frequency of multinucleated cells, suggesting an impairment in cytokinesis. Both phenotypes are reversed by transformation of cluA − cells with a plasmid carrying a constitutively expressed cluA gene. The predicted sequence of the cluA gene product is homologous to sequences encoded by open reading frames in the genomes of Saccharomyces cerevisiae and Caenorhabditis elegans, but not to any known protein. The only exception is a short region with some homology to the 42-residue imperfect repeats present in the kinesin light chain, which probably function in protein–protein interaction. These studies identify a new class of proteins that appear to be required for the proper distribution of mitochondria.
Footnotes
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↵ * Present address: University of Kentucky Medical Center, 800 Rose Street, Room MN523, Lexington, KY 40536-0084.
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↵ † To whom reprint requests should be addressed at: Program in Molecular and Cell Biology, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, OK 73104. e-mail: clarkem{at}omrf.uokhsc.edu.
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James A. Spudich, Stanford University, Stanford, CA
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Data deposition: The sequences reported in this paper have been deposited in the GenBank database [accession nos. of cluA and its homologues are U49332 (Dictyostelium discoideum), Z48613 (Saccharomyces cerevisiae), and P34466 (Caenorhabditis elegans)].
- ABBREVIATIONS:
- DAPI,
- 4′,6-diamidino-2-phenylindole;
- myosin-IC,
- an unconventional myosin of Acanthamoeba castellanii
- Copyright © 1997, The National Academy of Sciences of the USA
