Ultrastructure of COPII vesicle formation in yeast characterized by correlative light and electron microscopy

Melero, Alejandro; Boulanger, Jérôme; Kukulski, Wanda; Miller, Elizabeth A.

doi:10.1091/mbc.e22-03-0103

Cited by 7 publications

(4 citation statements)

References 53 publications

(75 reference statements)

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“…The ERES and cis-Golgi are in close proximity in yeast and plants [20,137], though contact sites are only transient in Saccharomyces cerevisiae [138]. COPII-coated vesicles have indeed been clearly visualised in these organisms, providing direct evidence for the mainstream model [139][140][141]. It is instead unclear whether vesicular transport also occurs in metazoa and/or if it is the sole mode of transport.…”

Section: Regulation In Metazoa: the Large Cargo Conundrum And The Rol...mentioning

confidence: 99%

The small GTPase Sar1, control centre of COPII trafficking

Verren

Zanetti

2023

FEBS Letters

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Edited by Jacqueline CherfilsSar1 is a small GTPase of the ARF family. Upon exchange of GDP for GTP, Sar1 associates with the endoplasmic reticulum (ER) membrane and recruits COPII components, orchestrating cargo concentration and membrane deformation. Many aspects of the role of Sar1 and regulation of its GTP cycle remain unclear, especially as complexity increases in higher organisms that secrete a wider range of cargoes. This review focusses on the regulation of GTP hydrolysis and its role in coat assembly, as well as the mechanism of Sar1-induced membrane deformation and scission. Finally, we highlight the additional specialisation in higher eukaryotes and the outstanding questions on how Sar1 functions are orchestrated.

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Section: Regulation In Metazoa: the Large Cargo Conundrum And The Rol...mentioning

confidence: 99%

The small GTPase Sar1, control centre of COPII trafficking

Verren

Zanetti

2023

FEBS Letters

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“…For instance, recent research has revealed that high curvature is a prerequisite for retromer to effectively enforce membrane curvature 27 . A pre-requisite for high curvature to facilitate budding is common in other organelles for various coats, including COPI 28 and COPII 29,30 . Our data show that Arp2/3 activity is required for trafficking from endosome to vacuole in fission yeast.…”

Section: Discussionmentioning

confidence: 99%

Arp2/3-dependent actin assembly shapes endosomes and promotes intracellular trafficking in fission yeast

Melero,

Muriel-Lopez,

Basante-Bedoya

et al. 2024

Preprint

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Endosomes serve as crucial sorting centres that streamline the distribution of cell surface proteins. The early endosome receives traffic from both the plasma membrane (PM) and the Golgi, and orchestrates the redistribution of cargoes for recycling to the PM or through retrograde movement to the Golgi, and for degradation to late endosomes and lysosomes. In animal cells and amoebae, Arp2/3-mediated F-actin assembly plays critical roles in many aspects of endosome function, from capturing cargo to generating the forces required for membrane deformation and creating cargo-enriched transport carriers, thus promoting both recycling and degradative trafficking routes. Yeast models, which allowed dissection of the major membrane trafficking routes, exhibit highly simplified endosomes, as shown in Saccharomyces cerevisiae, where the trans-Golgi network (TGN) functions as recycling endosome. Furthermore, there is no reported role for Arp2/3 or F-actin in endomembrane remodelling; in fact, the Arp2/3 activators on animal endosomes - the WASH complex promoting recycling of transmembrane receptors towards the PM or TGN, and Annexin A2 necessary for endosome maturation and the movement of cargoes towards the degradative pathway - do not exist in yeast cells. Here, we report that Arp2/3 and F-actin are present on fission yeast endosomes. Through live-imaging and correlative light-electron tomography, we demonstrate that Arp2/3 activity controls endosomal morphology and that this activity is essential for trafficking from the endosome to the degradative vacuole. Thus, Arp2/3-dependent actin assembly has a deeply conserved role in shaping and promoting the function of the endomembrane trafficking system.

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“…But why would a network of tubules be better than vesicles? Vesicles are seen in yeast 30,31 . However, mammalian cells have a more complex endomembrane organization and different secretory and metabolic needs.…”

Section: Discussionmentioning

confidence: 99%

Nanoscale imaging reveals the mechanisms of ER-to-Golgi transport via a dynamic tubular-vesicular network

Wong-Dilworth,

Bregu,

Restel

et al. 2023

Preprint

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The endoplasmic reticulum (ER) and the Golgi apparatus are the first sorting stations along the secretory pathway of mammalian cells and have a crucial role in protein quality control and cellular homeostasis. While machinery components mediating ER-to-Golgi transport have been mapped, it is unclear how exchange between the two closely juxtaposed organelles is coordinated in living cells. Here, using gene editing to tag machinery components, live-cell confocal and stimulated emission depletion (STED) super-resolution microscopy, we show that ER-to-Golgi transport occurs via a dynamic network of tubules positive for the small GTPase ARF4. COPI machinery is tightly associated to this network and moves with tubular-vesicular structures. Strikingly, the ARF4 network appears to be continuous with the ER and ARF4 tubules remodel around static ER exit sites (ERES) defined by COPII machinery. We were further able to dissect the steps of ER-to-Golgi transport with functional trafficking assays. A wave of cargo released from the ER percolates through peripheral and Golgi-tethered ARF4 structures before filling the cis-Golgi. Perturbation via acute degradation of ARF4 shows an active regulatory role for the GTPase and COPI in anterograde transport. Our data supports a model in which anterograde ER-to-Golgi transport occurs via an ARF4 tubular-vesicular network directly connecting the ER and Golgi-associated pre-cisternae.

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Ultrastructure of COPII vesicle formation in yeast characterized by correlative light and electron microscopy

Cited by 7 publications

References 53 publications

The small GTPase Sar1, control centre of COPII trafficking

The small GTPase Sar1, control centre of COPII trafficking

Arp2/3-dependent actin assembly shapes endosomes and promotes intracellular trafficking in fission yeast

Nanoscale imaging reveals the mechanisms of ER-to-Golgi transport via a dynamic tubular-vesicular network

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