A novel dynamin-related protein has been recruited for apicoplast fission in Toxoplasma gondii.
BACKGROUND
Apicomplexan parasites cause numerous important human diseases, including malaria and toxoplasmosis. Apicomplexa belong to the Alveolata, a group that also includes ciliates and dinoflagellates. Apicomplexa retain a plastid organelle (the apicoplast) that was derived from an endosymbiotic relationship between the alveolate ancestor and a red alga. Apicoplasts are essential for parasite growth and must correctly divide and segregate into daughter cells upon cytokinesis. Apicoplast division depends on association with the mitotic spindle, although little is known about the molecular machinery involved in this process. Apicoplasts lack the conserved machinery that divides chloroplasts in plants and red algae, suggesting that these mechanisms are unique.


RESULTS
Here, we demonstrate that a dynamin-related protein in Toxoplasma gondii (TgDrpA) localizes to punctate regions on the apicoplast surface. We generate a conditional dominant-negative TgDrpA cell line to disrupt TgDrpA functions and demonstrate that TgDrpA is essential for parasite growth and apicoplast biogenesis. Fluorescence recovery after photobleaching and time-lapse imaging studies provide evidence for a direct role for TgDrpA in apicoplast fission.


CONCLUSIONS
Our data suggest that DrpA was likely recruited from the alveolate ancestor to function in fission of the symbiont and ultimately replaced the conserved division machinery of that symbiont.
van Dooren
Giel G
GG
Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, 30602, USA.
Reiff
Sarah B
SB
Tomova
Cveta
C
Meissner
Markus
M
Humbel
Bruno M
BM
Striepen
Boris
B
D000818:Animals; D002478:Cells, Cultured; D034281:Dynamins / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D015388:Organelles / Q000378:metabolism* / Q000648:ultrastructure; D010802:Phylogeny; D015800:Protozoan Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014122:Toxoplasma / Q000166:cytology / Q000378:metabolism
D008869:Microtubule-Associated Proteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D034281:Dynamins