1
|
Scott CC, Wasnik V, Nunes-Hassler P, Demaurex N, Kruse K, Gruenberg J. Calcium storage in multivesicular endo-lysosome. Phys Biol 2023; 20. [PMID: 37769681 DOI: 10.1088/1478-3975/acfe6a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/28/2023] [Indexed: 10/03/2023]
Abstract
It is now established that endo-lysosomes, also referred to as late endosomes, serve as intracellular calcium store, in addition to the endoplasmic reticulum. While abundant calcium-binding proteins provide the latter compartment with its calcium storage capacity, essentially nothing is known about the mechanism responsible for calcium storage in endo-lysosomes. In this paper, we propose that the structural organization of endo-lysosomal membranes drives the calcium storage capacity of the compartment. Indeed, endo-lysosomes exhibit a characteristic multivesicular ultrastructure, with intralumenal membranes providing a large amount of additional bilayer surface. We used a theoretical approach to investigate the calcium storage capacity of endosomes, using known calcium binding affinities for bilayers and morphological data on endo-lysosome membrane organization. Finally, we tested our predictions experimentally after Sorting Nexin 3 depletion to decrease the intralumenal membrane content. We conclude that the major negatively-charge lipids and proteins of endo-lysosomes serve as calcium-binding molecules in the acidic calcium stores of mammalian cells, while the large surface area of intralumenal membranes provide the necessary storage capacity.
Collapse
Affiliation(s)
- Cameron C Scott
- Department of Biochemistry, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva, Switzerland
- CCS new address is: Genedata AG, Margarethenstrasse 38, 4053 Basel, Switzerland
| | - Vaibhav Wasnik
- Department of Biochemistry, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva, Switzerland
- NCCR Chemical Biology, Departments of Biochemistry and Theoretical Physics, University of Geneva, Geneva, Switzerland
- Wasnik's new address: Department of Physical Sciences, Indian Institute of Technology Goa, Ponda 403401, Goa, India
| | - Paula Nunes-Hassler
- Department of Cell Physiology and Metabolism, Rue Michel-Servet, 1, University of Geneva, Geneva, Switzerland
- PNH new address is: Department of Pathology and Immunology, Rue Michel-Servet, 1, University of Geneva, Geneva, Switzerland
| | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, Rue Michel-Servet, 1, University of Geneva, Geneva, Switzerland
| | - Karsten Kruse
- Department of Biochemistry, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva, Switzerland
- NCCR Chemical Biology, Departments of Biochemistry and Theoretical Physics, University of Geneva, Geneva, Switzerland
- Department of Theoretical Physics, University of Geneva, 24 Quai Ernest Ansermet, 1211 Geneva, Switzerland
| | - Jean Gruenberg
- Department of Biochemistry, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva, Switzerland
- NCCR Chemical Biology, Departments of Biochemistry and Theoretical Physics, University of Geneva, Geneva, Switzerland
| |
Collapse
|