ARC5, a cytosolic dynamin-like protein from plants, is part of the chloroplast division machinery
AUTOR(ES)
Gao, Hongbo
FONTE
The National Academy of Sciences
RESUMO
Chloroplast division in plant cells is orchestrated by a complex macromolecular machine with components positioned on both the inner and outer envelope surfaces. The only plastid division proteins identified to date are of endosymbiotic origin and are localized inside the organelle. Employing positional cloning methods in Arabidopsis in conjunction with a novel strategy for pinpointing the mutant locus, we have identified a gene encoding a new chloroplast division protein, ARC5. Mutants of ARC5 exhibit defects in chloroplast constriction, have enlarged, dumbbell-shaped chloroplasts, and are rescued by a wild-type copy of ARC5. The ARC5 gene product shares similarity with the dynamin family of GTPases, which mediate endocytosis, mitochondrial division, and other organellar fission and fusion events in eukaryotes. Phylogenetic analysis showed that ARC5 is related to a group of dynamin-like proteins unique to plants. A GFP–ARC5 fusion protein localizes to a ring at the chloroplast division site. Chloroplast import and protease protection assays indicate that the ARC5 ring is positioned on the outer surface of the chloroplast. Thus, ARC5 is the first cytosolic component of the chloroplast division complex to be identified. ARC5 has no obvious counterparts in prokaryotes, suggesting that it evolved from a dynamin-related protein present in the eukaryotic ancestor of plants. These results indicate that the chloroplast division apparatus is of mixed evolutionary origin and that it shares structural and mechanistic similarities with both the cell division machinery of bacteria and the dynamin-mediated organellar fission machineries of eukaryotes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=153092Documentos Relacionados
- Phragmoplastin, a dynamin-like protein associated with cell plate formation in plants.
- A dynamin-like protein (ADL2b), rather than FtsZ, is involved in Arabidopsis mitochondrial division
- Mammalian Dynamin-like Protein DLP1 Tubulates Membranes
- A New Dynamin-Like Protein, ADL6, Is Involved in Trafficking from the trans-Golgi Network to the Central Vacuole in Arabidopsis
- A dynamin-like protein, ADL1, is present in membranes as a high-molecular-mass complex in Arabidopsis thaliana.