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Genome-wide CRISPR/Cas9 screen shows that loss of GET4 increases mitochondria-endoplasmic reticulum contact sites and is neuroprotective.

Published version
Peer-reviewed

Repository DOI


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Authors

Leal, Nuno S 
Woodward, James A 

Abstract

Organelles form membrane contact sites between each other, allowing for the transfer of molecules and signals. Mitochondria-endoplasmic reticulum (ER) contact sites (MERCS) are cellular subdomains characterized by close apposition of mitochondria and ER membranes. They have been implicated in many diseases, including neurodegenerative, metabolic, and cardiac diseases. Although MERCS have been extensively studied, much remains to be explored. To uncover novel regulators of MERCS, we conducted a genome-wide, flow cytometry-based screen using an engineered MERCS reporter cell line. We found 410 genes whose downregulation promotes MERCS and 230 genes whose downregulation decreases MERCS. From these, 29 genes were selected from each population for arrayed screening and 25 were validated from the high population and 13 from the low population. GET4 and BAG6 were highlighted as the top 2 genes that upon suppression increased MERCS from both the pooled and arrayed screens, and these were subjected to further investigation. Multiple microscopy analyses confirmed that loss of GET4 or BAG6 increased MERCS. GET4 and BAG6 were also observed to interact with the known MERCS proteins, inositol 1,4,5-trisphosphate receptors (IP3R) and glucose-regulated protein 75 (GRP75). In addition, we found that loss of GET4 increased mitochondrial calcium uptake upon ER-Ca2+ release and mitochondrial respiration. Finally, we show that loss of GET4 rescues motor ability, improves lifespan and prevents neurodegeneration in a Drosophila model of Alzheimer's disease (Aβ42Arc). Together, these results suggest that GET4 is involved in decreasing MERCS and that its loss is neuroprotective.

Description

Acknowledgements: We thank the Cambridge Advanced Imaging Centre (CAIC) for EM sample preparation and sectioning. We also thank the Cambridge Institute for Medical Research (CIMR) Mass Spectrometry facility for conducting the mass spectrometry protocol and analysis. We thank the Vienna Drosophila RNAi Centre for fly stocks. We also wish to say thank you to Tom Smith for proofreading the paper and providing independent input.


Funder: UK DRI Grant RRZA/175


Funder: Medical Research Council UK (MC_UU_00028/5)


Funder: UK Medical Research Council, intramural project MC_UU_00025/3 (RG94521)

Keywords

CRISPR-Cas Systems, Mitochondria Associated Membranes, Mitochondria, Mitochondrial Membranes, Endoplasmic Reticulum, Calcium

Journal Title

Cell Death Dis

Conference Name

Journal ISSN

2041-4889
2041-4889

Volume Title

15

Publisher

Springer Science and Business Media LLC
Sponsorship
Medical Research Council (MC_UU_00025/3)