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Su KC, Radul E, Maier NK, Tsang MJ, Goul C, Moodie B, Keys HR, Cheeseman IM. Functional genetics reveals modulators of anti-microtubule drug sensitivity. bioRxiv 2024:2024.03.12.584469. [PMID: 38559203 PMCID: PMC10979949 DOI: 10.1101/2024.03.12.584469] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Microtubules play essential roles in diverse cellular processes and are important pharmacological targets for treating human disease. Here, we sought to identify cellular factors that modulate the sensitivity of cells to anti-microtubule drugs. We conducted a genome-wide CRISPR/Cas9-based functional genetics screen in human cells treated with the microtubule-destabilizing drug nocodazole or the microtubule-stabilizing drug taxol. We further conducted a focused secondary screen to test drug sensitivity for ~1400 gene targets across two distinct human cell lines and to additionally test sensitivity to the Kif11-inhibitor, STLC. These screens defined gene targets whose loss enhances or suppresses sensitivity to anti-microtubule drugs. In addition to gene targets whose loss sensitized cells to multiple compounds, we observed cases of differential sensitivity to specific compounds and differing requirements between cell lines. Our downstream molecular analysis further revealed additional roles for established microtubule-associated proteins and identified new players in microtubule function.
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Affiliation(s)
- Kuan-Chung Su
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142
- These authors contributed equally
| | - Elena Radul
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142
- These authors contributed equally
- Present address: Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Nolan K Maier
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
- These authors contributed equally
- Present address: Department of Microbiology, Harvard Medical School, Boston, MA
| | - Mary-Jane Tsang
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142
- These authors contributed equally
- Present address: Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Claire Goul
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
- Present address: Department of Molecular and Cellular Biology, UC Berkeley, Berkeley, CA
| | - Brittania Moodie
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142
| | - Heather R. Keys
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
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2
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Inglis AJ, Guna A, Gálvez-Merchán Á, Pal A, Esantsi TK, Keys HR, Frenkel EM, Oania R, Weissman JS, Voorhees RM. Coupled protein quality control during nonsense-mediated mRNA decay. J Cell Sci 2023; 136:310674. [PMID: 37218462 DOI: 10.1242/jcs.261216] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 04/10/2023] [Indexed: 05/24/2023] Open
Abstract
Translation of mRNAs containing premature termination codons (PTCs) results in truncated protein products with deleterious effects. Nonsense-mediated decay (NMD) is a surveillance pathway responsible for detecting PTC containing transcripts. Although the molecular mechanisms governing mRNA degradation have been extensively studied, the fate of the nascent protein product remains largely uncharacterized. Here, we use a fluorescent reporter system in mammalian cells to reveal a selective degradation pathway specifically targeting the protein product of an NMD mRNA. We show that this process is post-translational and dependent on the ubiquitin proteasome system. To systematically uncover factors involved in NMD-linked protein quality control, we conducted genome-wide flow cytometry-based screens. Our screens recovered known NMD factors but suggested that protein degradation did not depend on the canonical ribosome-quality control (RQC) pathway. A subsequent arrayed screen demonstrated that protein and mRNA branches of NMD rely on a shared recognition event. Our results establish the existence of a targeted pathway for nascent protein degradation from PTC containing mRNAs, and provide a reference for the field to identify and characterize required factors.
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Affiliation(s)
- Alison J Inglis
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Alina Guna
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Ángel Gálvez-Merchán
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Akshaye Pal
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Theodore K Esantsi
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Heather R Keys
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Evgeni M Frenkel
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Robert Oania
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Jonathan S Weissman
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute Technology, Cambridge, MA 02142, USA
| | - Rebecca M Voorhees
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
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3
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Abstract
A complete understanding of the genetic determinants underlying mammalian physiology and disease is limited by the capacity for high-throughput genetic dissection in the living organism. Genome-wide CRISPR screening is a powerful method for uncovering the genetic regulation of cellular processes, but the need to stably deliver single guide RNAs to millions of cells has largely restricted its implementation to ex vivo systems. There thus remains a need for accessible high-throughput functional genomics in vivo. Here, we establish genome-wide screening in the liver of a single mouse and use this approach to uncover regulation of hepatocyte fitness. We uncover pathways not identified in cell culture screens, underscoring the power of genetic dissection in the organism. The approach we developed is accessible, scalable, and adaptable to diverse phenotypes and applications. We have hereby established a foundation for high-throughput functional genomics in a living mammal, enabling comprehensive investigation of physiology and disease.
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Affiliation(s)
- Heather R. Keys
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Kristin A. Knouse
- Koch Institute for Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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4
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Winter JM, Fresenius HL, Cunningham CN, Wei P, Keys HR, Berg J, Bott A, Yadav T, Ryan J, Sirohi D, Tripp SR, Barta P, Agarwal N, Letai A, Sabatini DM, Wohlever ML, Rutter J. Collateral deletion of the mitochondrial AAA+ ATPase ATAD1 sensitizes cancer cells to proteasome dysfunction. eLife 2022; 11:82860. [PMID: 36409067 DOI: 10.7554/elife.82860] [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: 08/20/2022] [Accepted: 11/20/2022] [Indexed: 11/23/2022] Open
Abstract
The tumor suppressor gene PTEN is the second most commonly deleted gene in cancer. Such deletions often include portions of the chromosome 10q23 locus beyond the bounds of PTEN itself, which frequently disrupts adjacent genes. Coincidental loss of PTEN-adjacent genes might impose vulnerabilities that could either affect patient outcome basally or be exploited therapeutically. Here, we describe how the loss of ATAD1, which is adjacent to and frequently co-deleted with PTEN, predisposes cancer cells to apoptosis triggered by proteasome dysfunction and correlates with improved survival in cancer patients. ATAD1 directly and specifically extracts the pro-apoptotic protein BIM from mitochondria to inactivate it. Cultured cells and mouse xenografts lacking ATAD1 are hypersensitive to clinically used proteasome inhibitors, which activate BIM and trigger apoptosis. This work furthers our understanding of mitochondrial protein homeostasis and could lead to new therapeutic options for the hundreds of thousands of cancer patients who have tumors with chromosome 10q23 deletion.
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Affiliation(s)
- Jacob M Winter
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Heidi L Fresenius
- Department of Chemistry & Biochemistry, University of Toledo, Toledo, United States
| | - Corey N Cunningham
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Peng Wei
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Heather R Keys
- Whitehead Institute for Biomedical Research, Cambridge, United States
| | - Jordan Berg
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Alex Bott
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Tarun Yadav
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Jeremy Ryan
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, United States
| | - Deepika Sirohi
- University of Utah and ARUP Laboratories, Salt Lake City, United States
| | - Sheryl R Tripp
- University of Utah and ARUP Laboratories, Salt Lake City, United States
| | - Paige Barta
- Department of Biochemistry, University of Utah, Salt Lake City, United States
| | - Neeraj Agarwal
- Huntsman Cancer Institute, University of Utah, Salt Lake City, United States
| | - Anthony Letai
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, United States
| | - David M Sabatini
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Matthew L Wohlever
- Department of Chemistry & Biochemistry, University of Toledo, Toledo, United States
| | - Jared Rutter
- Department of Biochemistry, University of Utah, Salt Lake City, United States.,Huntsman Cancer Institute, University of Utah, Salt Lake City, United States.,Howard Hughes Medical Institute, Salt Lake City, United States
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5
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Rossiter NJ, Huggler KS, Adelmann CH, Keys HR, Soens RW, Sabatini DM, Cantor JR. CRISPR screens in physiologic medium reveal conditionally essential genes in human cells. Cell Metab 2021; 33:1248-1263.e9. [PMID: 33651980 PMCID: PMC8172426 DOI: 10.1016/j.cmet.2021.02.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 11/04/2020] [Accepted: 02/03/2021] [Indexed: 12/18/2022]
Abstract
Forward genetic screens across hundreds of cancer cell lines have started to define the genetic dependencies of proliferating human cells and how these vary by genotype and lineage. Most screens, however, have been carried out in culture media that poorly reflect metabolite availability in human blood. Here, we performed CRISPR-based screens in traditional versus human plasma-like medium (HPLM). Sets of conditionally essential genes in human cancer cell lines span several cellular processes and vary with both natural cell-intrinsic diversity and the combination of basal and serum components that comprise typical media. Notably, we traced the causes for each of three conditional CRISPR phenotypes to the availability of metabolites uniquely defined in HPLM versus conventional media. Our findings reveal the profound impact of medium composition on gene essentiality in human cells, and also suggest general strategies for using genetic screens in HPLM to uncover new cancer vulnerabilities and gene-nutrient interactions.
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Affiliation(s)
| | - Kimberly S Huggler
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Charles H Adelmann
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Heather R Keys
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Ross W Soens
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
| | - Jason R Cantor
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; University of Wisconsin Carbone Cancer Center, Madison, WI 53705, USA.
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6
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Tsvetkov P, Detappe A, Cai K, Keys HR, Brune Z, Ying W, Thiru P, Reidy M, Kugener G, Rossen J, Kocak M, Kory N, Tsherniak A, Santagata S, Whitesell L, Ghobrial IM, Markley JL, Lindquist S, Golub TR. Author Correction: Mitochondrial metabolism promotes adaptation to proteotoxic stress. Nat Chem Biol 2019; 15:757. [PMID: 31164776 DOI: 10.1038/s41589-019-0315-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Affiliation(s)
| | - Alexandre Detappe
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - Kai Cai
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI, USA
| | - Heather R Keys
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Zarina Brune
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Weiwen Ying
- OnTarget Pharmaceutical Consulting LLC, Lexington, MA, USA
| | - Prathapan Thiru
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Mairead Reidy
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | | | - Jordan Rossen
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Mustafa Kocak
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Nora Kory
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | | | - Sandro Santagata
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Ludwig Center at Harvard, Harvard Medical School, Boston, MA, USA
| | - Luke Whitesell
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.,Molecular Genetics Department, University of Toronto, Toronto, ON, Canada
| | - Irene M Ghobrial
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - John L Markley
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI, USA
| | - Susan Lindquist
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Todd R Golub
- Broad Institute of Harvard and MIT, Cambridge, MA, USA. .,Howard Hughes Medical Institute, Chevy Chase, MD, USA. .,Harvard Medical School, Boston, MA, USA. .,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
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7
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Tsvetkov P, Detappe A, Cai K, Keys HR, Brune Z, Ying W, Thiru P, Reidy M, Kugener G, Rossen J, Kocak M, Kory N, Tsherniak A, Santagata S, Whitesell L, Ghobrial IM, Markley JL, Lindquist S, Golub TR. Mitochondrial metabolism promotes adaptation to proteotoxic stress. Nat Chem Biol 2019; 15:681-689. [PMID: 31133756 PMCID: PMC8183600 DOI: 10.1038/s41589-019-0291-9] [Citation(s) in RCA: 255] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 04/16/2019] [Indexed: 12/17/2022]
Abstract
The mechanisms by which cells adapt to proteotoxic stress are largely unknown, but key to understanding how tumor cells, particularly in vivo, are largely resistant to proteasome inhibitors. Analysis of cancer cell lines, mouse xenografts and patient-derived tumor samples all showed an association between mitochondrial metabolism and proteasome inhibitor sensitivity. When cells were forced to use oxidative phosphorylation rather than glycolysis, they became proteasome inhibitor-resistant. This mitochondrial state, however, creates a unique vulnerability: sensitivity to the small-molecule compound elesclomol. Genome-wide CRISPR/Cas9 screening showed that a single gene, encoding the mitochondrial reductase FDX1, could rescue elesclomol-induced cell death. Enzymatic function and NMR-based analyses further showed that FDX1 is the direct target of elesclomol, which promotes a unique form of copper-dependent cell death. These studies elucidate a fundamental mechanism by which cells adapt to proteotoxic stress and suggests strategies to mitigate proteasome inhibitor-resistance.
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Affiliation(s)
| | - Alexandre Detappe
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - Kai Cai
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI, USA
| | - Heather R Keys
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Zarina Brune
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Weiwen Ying
- OnTarget Pharmaceutical Consulting LLC, Lexington, MA, USA
| | - Prathapan Thiru
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Mairead Reidy
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | | | - Jordan Rossen
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Mustafa Kocak
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Nora Kory
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | | | - Sandro Santagata
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Ludwig Center at Harvard, Harvard Medical School, Boston, MA, USA
| | - Luke Whitesell
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.,Molecular Genetics Department, University of Toronto, Toronto, ON, Canada
| | - Irene M Ghobrial
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - John L Markley
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI, USA
| | - Susan Lindquist
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.,Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Todd R Golub
- Broad Institute of Harvard and MIT, Cambridge, MA, USA. .,Howard Hughes Medical Institute, Chevy Chase, MD, USA. .,Harvard Medical School, Boston, MA, USA. .,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
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8
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Kory N, Wyant GA, Prakash G, Uit de Bos J, Bottanelli F, Pacold ME, Chan SH, Lewis CA, Wang T, Keys HR, Guo YE, Sabatini DM. SFXN1 is a mitochondrial serine transporter required for one-carbon metabolism. Science 2019; 362:362/6416/eaat9528. [PMID: 30442778 DOI: 10.1126/science.aat9528] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/17/2018] [Indexed: 12/12/2022]
Abstract
One-carbon metabolism generates the one-carbon units required to synthesize many critical metabolites, including nucleotides. The pathway has cytosolic and mitochondrial branches, and a key step is the entry, through an unknown mechanism, of serine into mitochondria, where it is converted into glycine and formate. In a CRISPR-based genetic screen in human cells for genes of the mitochondrial pathway, we found sideroflexin 1 (SFXN1), a multipass inner mitochondrial membrane protein of unclear function. Like cells missing mitochondrial components of one-carbon metabolism, those null for SFXN1 are defective in glycine and purine synthesis. Cells lacking SFXN1 and one of its four homologs, SFXN3, have more severe defects, including being auxotrophic for glycine. Purified SFXN1 transports serine in vitro. Thus, SFXN1 functions as a mitochondrial serine transporter in one-carbon metabolism.
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Affiliation(s)
- Nora Kory
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Department of Biology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 415 Main Street, Cambridge, MA 02142, USA
| | - Gregory A Wyant
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Department of Biology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 415 Main Street, Cambridge, MA 02142, USA
| | - Gyan Prakash
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Jelmi Uit de Bos
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Francesca Bottanelli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Michael E Pacold
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Department of Biology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 415 Main Street, Cambridge, MA 02142, USA.,Department of Radiation Oncology at NYU Langone Medical Center, New York, NY 10016, USA
| | - Sze Ham Chan
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Caroline A Lewis
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Tim Wang
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Department of Biology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 415 Main Street, Cambridge, MA 02142, USA
| | - Heather R Keys
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Yang Eric Guo
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA. .,Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Department of Biology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, 415 Main Street, Cambridge, MA 02142, USA
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9
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Thoreen CC, Chantranupong L, Keys HR, Wang T, Gray NS, Sabatini DM. A unifying model for mTORC1-mediated regulation of mRNA translation. Nature 2012; 485:109-13. [PMID: 22552098 PMCID: PMC3347774 DOI: 10.1038/nature11083] [Citation(s) in RCA: 1049] [Impact Index Per Article: 87.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 03/29/2012] [Indexed: 02/07/2023]
Abstract
The mTOR Complex 1 (mTORC1) kinase nucleates a pathway that promotes cell growth and proliferation and is the target of rapamycin, a drug with many clinical uses1. mTORC1 regulates mRNA translation, but the overall translational program is poorly defined and no unifying model exists to explain how mTORC1 differentially controls the translation of specific mRNAs. Here we use high-resolution transcriptome-scale ribosome profiling to monitor translation in cells acutely treated with the mTOR inhibitor Torin1, which, unlike rapamycin, fully inhibits mTORC12. These data reveal a surprisingly simple view of the mRNA features and mechanisms that confer mTORC1-dependent translation control. The subset of mRNAs that are specifically regulated by mTORC1 consists almost entirely of transcripts with established 5′ terminal oligopyrimidine (TOP) motifs, or, like Hsp90ab1 and Ybx1, with previously unrecognized TOP or related TOP-like motifs that we identified. We find no evidence to support proposals that mTORC1 preferentially regulates mRNAs with increased 5′ UTR length or complexity3. mTORC1 phosphorylates a myriad of translational regulators, but how it controls TOP mRNA translation is unknown4. Remarkably, loss of just the well-characterized mTORC1 substrates, the 4E-BP family of translational repressors, is sufficient to render TOP and TOP-like mRNA translation resistant to Torin1. The 4E-BPs inhibit translation initiation by interfering with the interaction between the cap-binding protein eIF4E and eIF4G1. Loss of this interaction diminishes the capacity of eIF4E to bind TOP and TOP-like mRNAs much more than other mRNAs, explaining why mTOR inhibition selectively suppresses their translation. Our results clarify the translational program controlled by mTORC1 and identify 4E-BPs and eIF4G1 as its master effectors.
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Affiliation(s)
- Carson C Thoreen
- Department of Cancer Biology, Dana Farber Cancer Institute, 250 Longwood Avenue, Boston, Massachusetts 02115, USA
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10
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Abstract
The DExD/H-box Prp5 protein (Prp5p) is an essential, RNA-dependent ATPase required for pre-spliceosome formation during nuclear pre-mRNA splicing. In order to understand how this protein functions, we used in vitro, biochemical assays to examine its association with the spliceosome from Saccharomyces cerevisiae. GST-Prp5p in splicing assays pulls down radiolabeled pre-mRNA as well as splicing intermediates and lariat product, but reduced amounts of spliced mRNA. It cosediments with active spliceosomes isolated by glycerol gradient centrifugation. In ATP-depleted extracts, GST-Prp5p associates with pre-mRNA even in the absence of spliceosomal snRNAs. Maximal selection in either the presence or absence of ATP requires a pre-mRNA with a functional intron. Prp5p is present in the commitment complex and functions in subsequent pre-spliceosome formation. Reduced Prp5p levels decrease levels of commitment, pre-spliceosomal and spliceosomal complexes. Thus Prp5p is most likely an integral component of the spliceosome, being among the first splicing factors associating with pre-mRNA and remaining until spliceosome disassembly. The results suggest a model in which Prp5p recruits the U2 snRNP to pre-mRNA in the commitment complex and then hydrolyzes ATP to promote stable association of U2 in the pre-spliceosome. They also suggest that Prp5p could have multiple ATP-independent and ATP-dependent functions at several stages of the splicing cycle.
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Affiliation(s)
- Tomasz R Kosowski
- Department of Molecular Genetics and Microbiology, Albuquerque, New Mexico 87131, USA
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