ER exit sites in Drosophila display abundant ER-Golgi vesicles and pearled tubes but no megacarriers

March 09, 2021

Ke Yang (1), Min Liu (1), Zhi Feng (1), Marta Rojas (2), Lingjian Zhou (1), Hongmei Ke (1), José Carlos Pastor-Pareja (1,3)

bioRxiv, 2021. DOI: 10.1101/2021.03.09.434528


Traffic; Secretion; Intermediate compartment; ERGIC; Golgi; Tango1


Secretory cargos are collected at ER exit sites (ERES) before transport to the Golgi apparatus. Decades of research have provided many details of the molecular events underlying ER-Golgi exchanges. Essential questions, however, remain about the organization of the ER-Golgi interface in cells and the type of membrane structures mediating traffic from ERES. To investigate these, we used transgenic tagging in Drosophila flies, 3D-SIM and FIB-SEM to characterize ERES-Golgi units in collagen-producing fat body, imaginal discs and imaginal discs overexpressing ERES determinant Tango1. We found in front of ERES a pre-cis-Golgi region involved in both anterograde and retrograde transport. This pre-cis-Golgi is continuous with the rest of the Golgi, not a separate intermediate compartment or collection of large carriers, for which we found no evidence. We found, however, many vesicles, as well as pearled tubules connecting ERES and Golgi.

How Our Software Was Used

Dragonfly was used to construct 3D models of 15 fat body and 15 wing disc ERES-Golgi units. Plus, its Movie Maker tools were used to create movies of rotating ERES-Golgi units.

Author Affiliation

(1) School of Life Sciences, Tsinghua University, Beijing, China
(2) School of Medicine, Tsinghua University, Beijing, China
(3) Tsinghua-Peking Center for Life Sciences, Beijing, China