The Golgi complex is responsible for processing and sorting of secretory cargos. Microtubules are known to accelerate the transport of proteins from the endoplasmic reticulum (ER) to the Golgi complex and from the Golgi to the plasma membrane. However, whether post-Golgi transport strictly requires microtubules is still unclear. Using the retention using selective hooks (RUSH) system to synchronize the trafficking of cargos, we show that anterograde transport of tumor necrosis factor (TNF) is strongly reduced without microtubules. We show that two populations of Golgi elements co-exist in these cells. A centrally located and giantin-positive Golgi complex that sustains trafficking, and newly formed peripheral Golgi mini-stacks that accumulate cargos in cells without microtubules. Using a genome-edited GFP–giantin cell line, we observe that the trafficking-competent Golgi population corresponds to the pre-existing population that was present before removal of microtubules. All Golgi elements support trafficking after long-term depletion of microtubules and after relocation of Golgi proteins to the ER after treatment with Brefeldin A. Our results demonstrate that functional maturation of Golgi elements is needed to ensure post-Golgi trafficking, and that microtubule-driven post-Golgi transport is not strictly required.
The authors declare no competing or financial interests.
L.F. carried out most of the experiments, analyzed the data and wrote the manuscript. S.D. performed some experiments and electron microscopy experiments. M.R. established the gene-edited GFP–giantin cell line. G.B. and F.P. designed the study, directed the work, analyzed the data and wrote the manuscript.
Electron microscopy work was supported by the Agence Nationale de la Recherche through the ‘Investments for the Future’ program (France-BioImaging) [grant number ANR-10-INSB-04]. We acknowledge the BioImaging Cell and Tissue Core Facility of the Institut Curie (PICT-IBiSA), a member of the France-BioImaging national research infrastructure, supported by the CelTisPhyBio Labex [grant number ANR-10-LBX-0038] part of the IDEX PSL [grant number ANR-10-IDEX-0001-02 PSL]. The work in the laboratory of F.P. was supported by the Institut Curie, the Centre National de la Recherche Scientifique (CNRS) and by grants from the Fondation pour la Recherche Médicale [grant numbers DEQ20120323723 and FDT20150532154] and from the Agence Nationale de la Recherche [grant number ANR-12-BSV2-0003-01].
Supplementary information available online at http://jcs.biologists.org/lookup/doi/10.1242/jcs.188870.supplemental
- Received March 4, 2016.
- Accepted July 8, 2016.
- © 2016. Published by The Company of Biologists Ltd