3D visualization of mitochondrial solid-phase calcium stores in whole cells
- Weizmann Institute of Science, Israel
Abstract
The entry of calcium into mitochondria is central to metabolism, inter-organelle communication, and cell life/death decisions. Long-sought transporters involved in mitochondrial calcium influx and efflux have recently been identified. To obtain a unified picture of mitochondrial calcium utilization, a parallel advance in understanding the forms and quantities of mitochondrial calcium stores is needed. We present here the direct 3D visualization of mitochondrial calcium in intact mammalian cells using cryo-scanning transmission electron tomography (CSTET). Amorphous solid granules containing calcium and phosphorus were pervasive in the mitochondrial matrices of a variety of mammalian cell types. Analysis based on quantitative electron scattering revealed that these repositories are equivalent to molar concentrations of dissolved ions. These results demonstrate conclusively that calcium buffering in the mitochondrial matrix in live cells occurs by phase separation, and that solid-phase stores provide a major ion reservoir that can be mobilized for bioenergetics and signaling.
Article and author information
Author details
Funding
European Research Council under the European Union's Seventh Framework Programme, grand number 310649 (310649)
- Deborah Fass
I-CORE Program of the Planning and Budgeting Committee and the Israel Science Foundation (1775/12)
- Deborah Fass
Irving and Cherna Moskowitz Center for Nano and Bio-Nano Imaging at the Weizmann Institute of Science
- Sharon Grayer Wolf
Israel Science Foundation (1285/14)
- Michael Elbaum
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2017, Wolf et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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3D visualization of mitochondrial solid-phase calcium stores in whole cells
eLife 6:e29929.
https://doi.org/10.7554/eLife.29929
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