2025-05-16 基礎生物学研究所,東京大学,お茶の水女子大学,立命館大学
図1 植物におけるVAMP72の構造変化と液胞輸送経路の進化モデル
<関連情報>
- https://www.nibb.ac.jp/press/2025/05/16.html
- https://www.cell.com/current-biology/abstract/S0960-9822(25)00559-7
VAMP7の新機能化が植物特有の液胞輸送経路を開いた Neofunctionalization of VAMP7 opened up a plant-unique vacuolar transport pathway
Masaru Fujimoto ∙ Yutaro Shimizu ∙ Yoko Ito ∙ … ∙ Akihiko Nakano ∙ Tomohiro Uemura ∙ Takashi Ueda
Current Biology Published:May 13, 2025
DOI:https://doi.org/10.1016/j.cub.2025.04.062
Highlights
- An acidic insertion enabled VAMP72 to function in vacuolar trafficking in plants
- The insertion originated in the common ancestor of land plants and zygnematophytes
- Interaction with AP-4 redirected VAMP72 from the secretory to vacuolar trafficking
- Stepwise sequence changes of the insertion facilitated VAMP727 neofunctionalization
Summary
Each eukaryotic cell possesses a specialized membrane trafficking system that emerged through paralogous expansion followed by the neofunctionalization of trafficking machinery components, including soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) proteins, during evolution. We discovered that the acquisition of an acidic insertion in the polypeptide converted the secretory R-SNARE vesicle-associated membrane protein (VAMP)72 into a major component of plant vacuolar transport. The moderately acidic insertion, originating from alternative splicing in the common ancestor of zygnematophytes and embryophytes, conferred binding ability to the clathrin adapter protein complex-4 (AP-4) at the trans-Golgi network (TGN), partially redirecting the VAMP72 protein from the secretory to the vacuolar transport pathway. Increased acidity of the insertion in angiosperms further reinforced the interaction with AP-4, leading VAMP727 to discrete zoning during sorting at the TGN and a definitive conversion to endosomal localization. This stepwise neofunctionalization of VAMP72 provided an option for the development of the intricate and complex vacuolar transport system in extant angiosperms.
