Epithelial magnesium transport by TRPM6 is essential for prenatal development and adult survival
- Ludwig Maximilian University of Munich, Germany
- The University of Queensland, Australia
- Helmholtz Zentrum Munich, Germany
- German Institute of Human Nutrition, Germany
- Princeton Institute of Life Sciences, United States
- University of Würzburg, Germany
- LMU Munich, Germany
- Paracelsus Medical University, Austria
Abstract
Mg2+ regulates many physiological processes and signalling pathways. However, little is known about the mechanisms underlying the organismal balance of Mg2+. Capitalizing on a set of newly generated mouse models, we provide an integrated mechanistic model of the regulation of organismal Mg2+ balance during prenatal development and in adult mice by the ion channel TRPM6. We show that TRPM6 activity in the placenta and yolk sac is essential for embryonic development. In adult mice, TRPM6 is required in the intestine to maintain organismal Mg2+ balance, but is dispensable in the kidney. Trpm6 inactivation in adult mice leads to shortened lifespan, growth deficit and metabolic alterations indicative of impaired energy balance. Dietary Mg2+ supplementation not only rescues all phenotypes displayed by Trpm6-deficient adult mice, but also may extend the lifespan of wildtype mice. Hence, maintenance of organismal Mg2+ balance by TRPM6 is crucial for prenatal development and survival to adulthood.
Data availability
-
Whole-genome profiling of the liver transcriptome in Trpm6 gene deficient mice and control littermatesPublicly available at the NCBI Gene Expression Omnibus (accession no: GSE70457).
-
Data from: Epithelial magnesium transport by TRPM6 is essential for prenatal development and adult survivalAvailable at Dryad Digital Repository under a CC0 Public Domain Dedication.
-
Ingenuity Pathway Analysis (IPA) analysis of hepatic transcripts altered in Trpm6-deficient miceAvailable at Dryad Digital Repository under a CC0 Public Domain Dedication.
-
Metabolic profiling of the serum, liver and gastrocnemius muscle of Trpm6-deficient miceAvailable at Dryad Digital Repository under a CC0 Public Domain Dedication.
-
MATLAB code used for statistical analysis of survival distributions of control and dietary treated miceAvailable at Dryad Digital Repository under a CC0 Public Domain Dedication.
Article and author information
Author details
Funding
Deutsche Forschungsgemeinschaft (TRR 152-P15)
- Vladimir Chubanov
Deutsche Forschungsgemeinschaft (TRP 152-P15)
- Thomas Gudermann
Deutsche Forschungsgemeinschaft (TRP 152-P14)
- Susanna Zierler
Deutsche Forschungsgemeinschaft (SFB1123-A1)
- Emiel PC van der Vorst
- Christian Weber
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: Experiments involving animals were done in accordance with the EU Animal Welfare Act and were approved by the local councils on animal care (permit No 55.2-1-54-2532-134-13 from Government of Oberbayern, Germany, and permit No 2347-15-2014 from State Ministry of Brandenburg, Germany).
Copyright
© 2016, Chubanov 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.
Metrics
-
- 3,481
- views
-
- 546
- downloads
-
- 102
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Epithelial magnesium transport by TRPM6 is essential for prenatal development and adult survival
eLife 5:e20914.
https://doi.org/10.7554/eLife.20914
Further reading
-
- Chromosomes and Gene Expression
- Structural Biology and Molecular Biophysics
Type II nuclear receptors (T2NRs) require heterodimerization with a common partner, the retinoid X receptor (RXR), to bind cognate DNA recognition sites in chromatin. Based on previous biochemical and overexpression studies, binding of T2NRs to chromatin is proposed to be regulated by competition for a limiting pool of the core RXR subunit. However, this mechanism has not yet been tested for endogenous proteins in live cells. Using single-molecule tracking (SMT) and proximity-assisted photoactivation (PAPA), we monitored interactions between endogenously tagged RXR and retinoic acid receptor (RAR) in live cells. Unexpectedly, we find that higher expression of RAR, but not RXR, increases heterodimerization and chromatin binding in U2OS cells. This surprising finding indicates the limiting factor is not RXR but likely its cadre of obligate dimer binding partners. SMT and PAPA thus provide a direct way to probe which components are functionally limiting within a complex TF interaction network providing new insights into mechanisms of gene regulation in vivo with implications for drug development targeting nuclear receptors.
-
- Biochemistry and Chemical Biology
- Structural Biology and Molecular Biophysics
The SARS-CoV-2 main protease (Mpro or Nsp5) is critical for production of viral proteins during infection and, like many viral proteases, also targets host proteins to subvert their cellular functions. Here, we show that the human tRNA methyltransferase TRMT1 is recognized and cleaved by SARS-CoV-2 Mpro. TRMT1 installs the N2,N2-dimethylguanosine (m2,2G) modification on mammalian tRNAs, which promotes cellular protein synthesis and redox homeostasis. We find that Mpro can cleave endogenous TRMT1 in human cell lysate, resulting in removal of the TRMT1 zinc finger domain. Evolutionary analysis shows the TRMT1 cleavage site is highly conserved in mammals, except in Muroidea, where TRMT1 is likely resistant to cleavage. TRMT1 proteolysis results in reduced tRNA binding and elimination of tRNA methyltransferase activity. We also determined the structure of an Mpro-TRMT1 peptide complex that shows how TRMT1 engages the Mpro active site in an uncommon substrate binding conformation. Finally, enzymology and molecular dynamics simulations indicate that kinetic discrimination occurs during a later step of Mpro-mediated proteolysis following substrate binding. Together, these data provide new insights into substrate recognition by SARS-CoV-2 Mpro that could help guide future antiviral therapeutic development and show how proteolysis of TRMT1 during SARS-CoV-2 infection impairs both TRMT1 tRNA binding and tRNA modification activity to disrupt host translation and potentially impact COVID-19 pathogenesis or phenotypes.
