Visualizing structural dynamics of thylakoid membranes.
To optimize photosynthesis, light-harvesting antenna proteins regulate light energy dissipation and redistribution in chloroplast thylakoid membranes, which involve dynamic protein reorganization of photosystems I and II. However, direct evidence for such protein reorganization has not been visualized in live cells. Here we demonstrate structural dynamics of thylakoid membranes by live cell imaging in combination with deconvolution. We observed chlorophyll fluorescence in the antibiotics-induced macrochloroplast in the moss Physcomitrella patens. The three-dimensional reconstruction uncovered the fine thylakoid membrane structure in live cells. The time-lapse imaging shows that the entire thylakoid membrane network is structurally stable, but the individual thylakoid membrane structure is flexible in vivo. Our observation indicates that grana serve as a framework to maintain structural integrity of the entire thylakoid membrane network. Both the structural stability and flexibility of thylakoid membranes would be essential for dynamic protein reorganization under fluctuating light environments.
1] Live Cell Molecular Imaging Research Team, Extreme Photonics Research Group, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan [2] PRESTO, Japan Science and Technology Agency (JST), Honcho, Kawaguchi, Saitama 332-0012 Japan.
Masakazu
M
Iwai
Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido 060-0819 Japan.
Makio
M
Yokono
1] Live Cell Molecular Imaging Research Team, Extreme Photonics Research Group, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan [2] Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Akihiko
A
Nakano
D019068:Bryopsida / Q000235:genetics / Q000648:ultrastructure*; D002734:Chlorophyll / Q000737:chemistry*; D005453:Fluorescence; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000648:ultrastructure; D010788:Photosynthesis; D045331:Photosystem I Protein Complex / Q000648:ultrastructure; D045332:Photosystem II Protein Complex / Q000648:ultrastructure; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism* / Q000648:ultrastructure; D059008:Time-Lapse Imaging
D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll