The paper
Y. Yoshida et al., "Chloroplasts divide by contraction of a bundle of nanofilaments consisting of polyglucan," Science, 329:949-53, 2010. Free F1000 Evaluation
The finding
When a cell divides, it splits its organelles so that each daughter has the right starting material. But rather than using a band of proteins, Tsuneyoshi Kuroiwa at Rikkyo University and colleagues found that chloroplasts divide via a contractile ring made of starch-like fibers called polyglucans.
The surprise
Mitochondrial division occurs with the help of a contractile ring made from proteins, and although the mechanism in chloroplasts was unknown, researchers assumed it would be similar. Faculty Member Jim Umen calls it “pretty remarkable” that the structural element for division is a polysaccharide.
The squeeze
The red alga Cyanidioschyzon merolae only has a single chloroplast and mitochondrion, which divide synchronously during cell division. Kuroiwa’s group isolated the chloroplast’s dividing ring and used a combination of ...
