Visualizing insulin vesicle neighborhoods in β cells by cryo-electron tomography
Abstract
Subcellular neighborhoods, comprising specific ratios of organelles and proteins, serve a multitude of biological functions and are of particular importance in secretory cells. However, the role of subcellular neighborhoods in insulin vesicle maturation is poorly understood. Here, we present single-cell multiple distinct tomogram acquisitions of β cells for in situ visualization of distinct subcellular neighborhoods that are involved in the insulin vesicle secretory pathway. We propose that these neighborhoods play an essential role in the specific function of cellular material. In the regions where we observed insulin vesicles, a measurable increase in both the fraction of cellular volume occupied by vesicles and the average size (diameter) of the vesicles was apparent as sampling moved from the area near the nucleus toward the plasma membrane. These findings describe the important role of the nanometer-scale organization of subcellular neighborhoods on insulin vesicle maturation.
Additional Information
© 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY). Submitted 16 May 2020; Accepted 22 October 2020; Published 9 December 2020. We thank S. Chen and A. Malyutin for technical assistance with cryo–electron microscopy. Cryo–electron microscopy was performed in the Beckman Institute Resource Center for Transmission Electron Microscopy at Caltech. We thank K. Villers and C. Hanson for cell culture; W. Zhao for help with FIB milling; and C. Cato, A. Walker, and C. Oikonomou for assistance with manuscript preparation. We thank the members of the Pancreatic Beta Cell Consortium for their feedback and inspiring discussions. This work was supported by the USC Bridge Institute (R.C.S.) and NIH grant R35GM122588 to G.J.J. Author contributions: R.C.S. and G.J.J. designed the project. X.Z. prepared samples, collected and processed electron tomography data, and prepared figures and supplementary videos with help from S.D.C. J.S. helped with data analysis and prepared statistical graphs in Fig. 3. K.L.W. initiated the INS-1E cell studies and helped with the design of INS-1E experiments and biological data analysis. P.C.B. provided scientific input and helped with INS-1E cell data analysis. The manuscript was written by X.Z., J.S., R.C.S., and G.J.J. with contributions from all authors. Competing interests: R.C.S. is a founder of ShouTi, a biotech company focused on G protein–coupled receptor small-molecule drug discovery including diabetes research. R.C.S. acknowledges that his primary affiliation is with USC; he holds a secondary appointment at ShanghaiTech University/iHuman Institute. The other authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors.Attached Files
Published - eabc8258.full.pdf
Supplemental Material - abc8258_Movie_S1.mp4
Supplemental Material - abc8258_Movie_S2.mov
Supplemental Material - abc8258_Movie_S3.mov
Supplemental Material - abc8258_Movie_S4.mov
Supplemental Material - abc8258_Movie_S5.mov
Supplemental Material - abc8258_Movie_S6.mov
Supplemental Material - abc8258_SM.pdf
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Additional details
- PMCID
- PMC7725471
- Eprint ID
- 106975
- Resolver ID
- CaltechAUTHORS:20201209-113043013
- University of Southern California
- NIH
- R35GM122588
- Created
-
2020-12-09Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Division of Biology and Biological Engineering (BBE)