Cargo sorting zones in the trans-Golgi network visualized by super-resolution confocal live imaging microscopy in plants

Yutaro Shimizu,Kiminori Toyooka,Takashi Ueda,Yamato Komatsu,Emi Ito,Akihiko Nakano,Yoko Ito,Yumi Goto,Kazuo Kurokawa,Mayuko Sato,Kazuo Ebine,Junpei Takagi,Tomohiro Uemura

doi:10.1038/s41467-021-22267-0

Abstract

The trans-Golgi network (TGN) has been known as a key platform to sort and transport proteins to their final destinations in post-Golgi membrane trafficking. However, how the TGN sorts proteins with different destinies still remains elusive. Here, we examined 3D localization and 4D dynamics of TGN-localized proteins of Arabidopsis thaliana that are involved in either secretory or vacuolar trafficking from the TGN, by a multicolor high-speed and high-resolution spinning-disk confocal microscopy approach that we developed. We demonstrate that TGN-localized proteins exhibit spatially and temporally distinct distribution. VAMP721 (R-SNARE), AP (adaptor protein complex)−1, and clathrin which are involved in secretory trafficking compose an exclusive subregion, whereas VAMP727 (R-SNARE) and AP-4 involved in vacuolar trafficking compose another subregion on the same TGN. Based on these findings, we propose that the single TGN has at least two subregions, or “zones”, responsible for distinct cargo sorting: the secretory-trafficking zone and the vacuolar-trafficking zone.

Highlights

The trans-Golgi network (TGN) has been known as a key platform to sort and transport proteins to their final destinations in post-Golgi membrane trafficking
We compared the distribution of these proteins with fluorescent tags on the TGN by conventional confocal laser scanning microscopy (CLSM) and superresolution confocal live imaging microscopy (SCLIM)
Adaptor protein (AP)-1 and AP-4 are located in secretory- and vacuolartrafficking zones in the TGN, respectively. To investigate whether these trafficking zones labeled with the two R-SNAREs are responsible for cargo sorting, we focused our attention on the AP complexes AP-1 and AP-4

Summary

Introduction

The trans-Golgi network (TGN) has been known as a key platform to sort and transport proteins to their final destinations in post-Golgi membrane trafficking. VAMP721 (R-SNARE), AP (adaptor protein complex)−1, and clathrin which are involved in secretory trafficking compose an exclusive subregion, whereas VAMP727 (R-SNARE) and AP-4 involved in vacuolar trafficking compose another subregion on the same TGN. Based on these findings, we propose that the single TGN has at least two subregions, or “zones”, responsible for distinct cargo sorting: the secretory-trafficking zone and the vacuolartrafficking zone.

Methods

Results

Conclusion