Titre
Immuno-electron tomography of ER exit sites reveals the existence of free COPII-coated transport carriers.
Type
article
Institution
Externe
Périodique
Auteur(s)
Zeuschner, D.
Auteure/Auteur
Geerts, W.J.C.
Auteure/Auteur
van Donselaar, E.
Auteure/Auteur
Humbel, B.M.
Auteure/Auteur
Slot, J.W.
Auteure/Auteur
Koster, A.J.
Auteure/Auteur
Klumperman, J.
Auteure/Auteur
Liens vers les personnes
ISSN
1465-7392
Statut éditorial
Publié
Date de publication
2006
Volume
8
Numéro
4
Première page
377
Dernière page/numéro d’article
383
Langue
anglais
Résumé
Transport from the endoplasmic reticulum (ER) to the Golgi complex requires assembly of the COPII coat complex at ER exit sites. Recent studies have raised the question as to whether in mammalian cells COPII coats give rise to COPII-coated transport vesicles or instead form ER sub-domains that collect proteins for transport via non-coated carriers. To establish whether COPII-coated vesicles do exist in vivo, we developed approaches to combine quantitative immunogold labelling (to identify COPII) and three-dimensional electron tomography (to reconstruct entire membrane structures). In tomograms of both chemically fixed and high-pressure-frozen HepG2 cells, immuno-labelled COPII was found on ER-associated buds as well as on free approximately 50-nm diameter vesicles. In addition, we identified a novel type of COPII-coated structure that consists of partially COPII-coated, 150-200-nm long, dumb-bell-shaped tubules. Both COPII-coated carriers also contain the SNARE protein Sec22b, which is necessary for downstream fusion events. Our studies unambiguously establish the existence of free, bona fide COPII-coated transport carriers at the ER-Golgi interface, suggesting that assembly of COPII coats in vivo can result in vesicle formation.
Sujets
PID Serval
serval:BIB_6C8739D49F88
PMID
Date de création
2012-02-28T17:46:09.927Z
Date de création dans IRIS
2025-05-21T02:03:29Z