Isolated chloroplast division machinery can actively constrict after stretching.
Chloroplast division involves plastid-dividing, dynamin, and FtsZ (PDF) rings. We isolated intact supertwisted (or spiral) and circular PDF machineries from chloroplasts of the red alga Cyanidioschyzon merolae. After individual intact PDF machineries were stretched to four times their original lengths with optical tweezers, they spontaneously returned to their original sizes. Dynamin-released PDF machineries did not retain the spiral structure and could not be stretched. Thus, dynamin may generate the motive force for contraction by filament sliding in dividing chloroplasts, in addition to pinching-off the membranes.
Yoshida
Yamato
Y
Laboratory of Cell Biology, Department of Life Science, College of Science, Rikkyo (St. Paul's) University, Toshima, Tokyo 171-8501, Japan.
Kuroiwa
Haruko
H
Misumi
Osami
O
Nishida
Keiji
K
Yagisawa
Fumi
F
Fujiwara
Takayuki
T
Nanamiya
Hideaki
H
Kawamura
Fujio
F
Kuroiwa
Tsuneyoshi
T
D008841:Actin Cytoskeleton / Q000502:physiology* / Q000648:ultrastructure; D020418:Algal Proteins / Q000502:physiology*; D002736:Chloroplasts / Q000502:physiology* / Q000648:ultrastructure; D034281:Dynamins / Q000502:physiology*; D020558:GTP Phosphohydrolases / Q000502:physiology; D007425:Intracellular Membranes / Q000502:physiology / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D000461:Rhodophyta / Q000502:physiology* / Q000648:ultrastructure
D020418:Algal Proteins; D020558:GTP Phosphohydrolases; D034281:Dynamins