The Golgi ribbon structure facilitates anterograde transport of large cargoes.
Bottom Line: Yet the purpose of this remarkable structure has been an enigma.In addition, insect cells that naturally harbor dispersed Golgi stacks have limited capacity to transport artificial oversized cargoes.These results imply that the ribbon structure is an essential requirement for transport of large cargoes in mammalian cells, and we suggest that this is because it enables the dilated rims of cisternae (containing the aggregates) to move across the stack as they transfer among adjacent stacks within the ribbon structure.
Affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 email@example.com firstname.lastname@example.org.Show MeSH
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Mentions: First, we combined nocodazole treatment with a drug-controlled aggregation system that allows for positioning soluble aggregates at different stages of the secretory pathway (Volchuk et al., 2000; Lavieu et al., 2013). The chimeric cargo is constituted of a signal sequence fused to a fluorescent protein, four repeats of the self-aggregation domain (FM4), a furin cleavage site, and the sequence encoding the human growth hormone (Figure 1B). In the absence of the disaggregating drug, the chimeric protein is aggregated and stays in the endoplasmic reticulum (ER). In the presence of the drug, at 16°C for 2 h, the now-disaggregated protein reaches the cis face of the Golgi, where it can be reaggregated by subsequent drug removal. Shifting the temperature back to 37°C in the absence or presence of the disaggregating drug allows for comparison of intra-Golgi transport and further secretion of large aggregated cargo versus small disaggregated cargo, respectively. Importantly, such a chase needs to be performed in the presence of cycloheximide (CHX), an inhibitor of protein synthesis.
Affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 email@example.com firstname.lastname@example.org.