Video_7_Visualization of Protein Sorting at the Trans-Golgi Network and Endosomes Through Super-Resolution Imaging.AVI
The trans-Golgi network (TGN) and endosomes are essential protein sorting stations in the secretory transport pathway. Protein sorting is fundamentally a process of spatial segregation, but the spatial relationships among the proteins that constitute the sorting machinery have not been systematically analyzed at high resolution in mammalian cells. Here, using two-color STORM imaging, we show that the TGN/endosome-localized cargo adaptors, AP-1, GGA2 and epsinR, form elongated structures of over 250 nm in length at the juxta-nuclear Golgi area. Many of these structures are associated with clathrin. We found that AP-1 is spatially segregated from AP-3 and GGA2, whereas a fraction of AP-1 and GGA2 punctae are associated with epsinR. Moreover, we observed that the planar cell polarity cargo proteins, Vangl2 and Frizzled6 associate with different cargo adaptors—AP-1 and GGA2 or epsinR, respectively—when exiting the TGN. Knockdown analysis confirms the functional significance of this segregation. Our data indicates that TGN/endosome-localized cargo adaptors have distinct spatial relationships. The spatially segregated cargo adaptors GGA2 and AP-1 regulate sorting of Frizzled6 and Vangl2, respectively and spatially associated cargo adaptors can cooperatively regulate a specific sorting process.
History
References
- https://doi.org//10.20517/2394-4722.2017.22
- https://doi.org//10.1074/jbc.M113.453621
- https://doi.org//10.1073/pnas.1716892115
- https://doi.org//10.1091/mbc.e06-11-1000
- https://doi.org//10.1091/mbc.e06-05-0410
- https://doi.org//10.1091/mbc.e02-05-0309
- https://doi.org//10.1073/pnas.1615163114
- https://doi.org//10.1038/ncb2427
- https://doi.org//10.1111/j.1365-2818.2008.01949.x
- https://doi.org//10.1177/34.11.3534077
- https://doi.org//10.1091/mbc.e07-12-1236
- https://doi.org//10.1146/annurev-cellbio-100913-013012
- https://doi.org//10.7554/eLife.01328
- https://doi.org//10.1038/nmeth0510-339
- https://doi.org//10.1016/j.cub.2012.07.012
- https://doi.org//10.1091/mbc.E15-04-0245
- https://doi.org//10.1091/mbc.e04-06-0468
- https://doi.org//10.1091/mbc.e02-09-0552
- https://doi.org//10.1111/j.1600-0854.2009.00983.x
- https://doi.org//10.1126/science.1153529
- https://doi.org//10.1073/pnas.1708240114
- https://doi.org//10.1083/jcb.200709037
- https://doi.org//10.1128/mBio.00657-17
- https://doi.org//10.1074/jbc.RA118.001906
- https://doi.org//10.1242/dev.174615
- https://doi.org//10.1091/mbc.e07-02-0190
- https://doi.org//10.1016/j.devcel.2014.07.016
- https://doi.org//10.1038/ncb2002
- https://doi.org//10.1091/mbc.e05-06-0568
- https://doi.org//10.1146/annurev.cellbio.20.010403.104543
- https://doi.org//10.1083/jcb.200311064
- https://doi.org//10.1016/j.cell.2012.12.042
- https://doi.org//10.1104/pp.16.00754
- https://doi.org//10.1364/OE.23.001879