Two Dictyostelium orthologs of the prokaryotic cell division protein FtsZ localize to mitochondria and are required for the maintenance of normal mitochondrial morphology.
In bacteria, the protein FtsZ is the principal component of a ring that constricts the cell at division. Though all mitochondria probably arose through a single, ancient bacterial endosymbiosis, the mitochondria of only certain protists appear to have retained FtsZ, and the protein is absent from the mitochondria of fungi, animals, and higher plants. We have investigated the role that FtsZ plays in mitochondrial division in the genetically tractable protist Dictyostelium discoideum, which has two nuclearly encoded FtsZs, FszA and FszB, that are targeted to the inside of mitochondria. In most wild-type amoebae, the mitochondria are spherical or rod-shaped, but in fsz-null mutants they become elongated into tubules, indicating that a decrease in mitochondrial division has occurred. In support of this role in organelle division, antibodies to FszA and FszA-green fluorescent protein (GFP) show belts and puncta at multiple places along the mitochondria, which may define future or recent sites of division. FszB-GFP, in contrast, locates to an electron-dense, submitochondrial body usually located at one end of the organelle, but how it functions during division is unclear. This is the first demonstration of two differentially localized FtsZs within the one organelle, and it points to a divergence in the roles of these two proteins.
Gilson
Paul R
PR
Centre for Cellular and Molecular Biology, School of Biological and Chemical Sciences, Deakin University, Victoria 3125, Australia. gilson@wehi.edu.au
Yu
Xuan-Chuan
XC
Hereld
Dale
D
Barth
Christian
C
Savage
Amelia
A
Kiefel
Ben R
BR
Lay
Sui
S
Fisher
Paul R
PR
Margolin
William
W
Beech
Peter L
PL
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D020029:Base Pairing; D002455:Cell Division; D003598:Cytoskeletal Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D016054:DNA, Protozoan; D016208:Databases, Factual; D004023:Dictyostelium / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005456:Fluorescent Dyes; D017125:Genes, Protozoan; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009930:Organic Chemicals; D016133:Polymerase Chain Reaction; D011387:Prokaryotic Cells; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D016054:DNA, Protozoan; D005456:Fluorescent Dyes; C071525:FtsZ protein, Bacteria; D009930:Organic Chemicals; C107472:red dye CMXRos