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All roads lead to the vacuole

Three diversified vacuolar trafficking pathways in plants


Graduate School of Science / Faculty of Science

The plant vacuole is an organelle that, similar to the yeast vacuole or the animal lysosome, has the function of degrading unwanted materials. In contrast to yeast vacuoles and animal lysosomes, the plant vacuole also has the agriculturally-important role of storing nutrients including proteins and sugars. This function of the plant vacuole depends on the correct transport of and activities of proteins in the vacuole. However, it was not known how plants were able to transport multiple types of proteins to vacuoles.

© 2014 Kazuo Ebine.
Model of protein transport to the plant vacuole from donor organelles such as the ER, Golgi, and trans-Golgi network (TGN) revealed in the present study. At least three pathways operate vacuolar transport in plants: 1) RAB5- and RAB7-dependent, 2) RAB5-dependent but RAB7-independent, 3) RAB5- and RAB7-independent pathways. The third pathway requires a different component, AP3. Routes 2 and 3 suggest that plant vacuolar transport became more complex in the process of evolution. Each pathway carries a different protein: seed storage protein, SYP22 and VAMP 713 respectively.

Associate Professor Takashi Ueda and Project Researcher Kazuo Ebine’s research group at the University of Tokyo Graduate School of Science used Arabidopsis thaliana to examine the mechanism by which proteins were transported to plant vacuoles. The group found that, in addition to the route shared with other organisms, plants have at least two other routes for transporting proteins to vacuoles.

From this result, the research group concluded that plants, by having evolved a vacuolar transport system far more complicated than that of animals, were able to develop vacuoles with diverse and complicated functions. Optimizing and strengthening the protein functions and the storage capacity of plant vacuoles may lead to the development of functionally improved plants.

Press release (Japanese)


Kazuo Ebine, Takeshi Inoue, Jun Ito, Emi Ito, Tomohiro Uemura, Tatsuaki Goh, Hiroshi Abe, Ken Sato, Akihiko Nakano, and Takashi Ueda,
“Plant vacuolar trafficking occurs through distinctly regulated pathways”,
Current Biology Online Edition: 2014/5/29, doi: 10.1016/j.cub.2014.05.004.
Article link


Graduate School of Science

Department of Biological Sciences, Graduate School of Science

Laboratory of Developmental Cell Biology, Department of Biological Sciences, Graduate School of Science

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