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: We then assessed the intracellular localization of the nonsecreted fraction of the reaggregated protein using confocal microscopy. Working with nocodazole-induced ministacks allows for discriminating cis- from trans-Golgi cisternae, even at the light microscopy level (Dejgaard et al., 2007). Within the very same cells, the localization of the green fluorescent protein (GFP)-tagged disaggregated or aggregated cargo was compared with a cis-Golgi marker (Gpp130 labeled with a red dye) and a trans-Golgi marker (p230 labeled with a far-red dye). As expected, cis- and trans-Golgi markers were easily distinguishable, as judged by the lack of overlay and the low Pearson's coefficient value (Figure 2, A and B). At 16°C, the disaggregated cargo was specifically colocalizing with the cis-Golgi marker (Figure 2, A and B, condition I). When the cells were subsequently incubated at 20°C, a large portion of the disaggregated cargo reached the trans-Golgi (Figure 2, A and B, condition II), whereas the reaggregated cargo remained associated with the cis-Golgi cisternae (Figure 2, A and B, condition III). We observed the same cis-Golgi retention of the aggregates when the chase was performed at 37°C (Supplemental Figure S1).
Affiliation: Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 email@example.com firstname.lastname@example.org.