1
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Gupta M, Johnson ANT, Cruz ER, Costa EJ, Guest RL, Li SHJ, Hart EM, Nguyen T, Stadlmeier M, Bratton BP, Silhavy TJ, Wingreen NS, Gitai Z, Wühr M. Global protein turnover quantification in Escherichia coli reveals cytoplasmic recycling under nitrogen limitation. Nat Commun 2024; 15:5890. [PMID: 39003262 PMCID: PMC11246515 DOI: 10.1038/s41467-024-49920-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 06/25/2024] [Indexed: 07/15/2024] Open
Abstract
Protein turnover is critical for proteostasis, but turnover quantification is challenging, and even in well-studied E. coli, proteome-wide measurements remain scarce. Here, we quantify the turnover rates of ~3200 E. coli proteins under 13 conditions by combining heavy isotope labeling with complement reporter ion quantification and find that cytoplasmic proteins are recycled when nitrogen is limited. We use knockout experiments to assign substrates to the known cytoplasmic ATP-dependent proteases. Surprisingly, none of these proteases are responsible for the observed cytoplasmic protein degradation in nitrogen limitation, suggesting that a major proteolysis pathway in E. coli remains to be discovered. Lastly, we show that protein degradation rates are generally independent of cell division rates. Thus, we present broadly applicable technology for protein turnover measurements and provide a rich resource for protein half-lives and protease substrates in E. coli, complementary to genomics data, that will allow researchers to study the control of proteostasis.
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Affiliation(s)
- Meera Gupta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Alex N T Johnson
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Edward R Cruz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Eli J Costa
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Randi L Guest
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | | | - Elizabeth M Hart
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Thao Nguyen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Michael Stadlmeier
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Benjamin P Bratton
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Vanderbilt Institute of Infection, Immunology and Inflammation, Nashville, TN, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Thomas J Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Ned S Wingreen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Martin Wühr
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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2
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Arunachalam E, Keber FC, Law RC, Kumar CK, Shen Y, Park JO, Wühr M, Needleman DJ. Robustness of mitochondrial biogenesis and respiration explain aerobic glycolysis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.04.601975. [PMID: 39005310 PMCID: PMC11245115 DOI: 10.1101/2024.07.04.601975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
A long-standing observation is that in fast-growing cells, respiration rate declines with increasing growth rate and is compensated by an increase in fermentation, despite respiration being more efficient than fermentation. This apparent preference for fermentation even in the presence of oxygen is known as aerobic glycolysis, and occurs in bacteria, yeast, and cancer cells. Considerable work has focused on understanding the potential benefits that might justify this seemingly wasteful metabolic strategy, but its mechanistic basis remains unclear. Here we show that aerobic glycolysis results from the saturation of mitochondrial respiration and the decoupling of mitochondrial biogenesis from the production of other cellular components. Respiration rate is insensitive to acute perturbations of cellular energetic demands or nutrient supplies, and is explained simply by the amount of mitochondria per cell. Mitochondria accumulate at a nearly constant rate across different growth conditions, resulting in mitochondrial amount being largely determined by cell division time. In contrast, glucose uptake rate is not saturated, and is accurately predicted by the abundances and affinities of glucose transporters. Combining these models of glucose uptake and respiration provides a quantitative, mechanistic explanation for aerobic glycolysis. The robustness of specific respiration rate and mitochondrial biogenesis, paired with the flexibility of other bioenergetic and biosynthetic fluxes, may play a broad role in shaping eukaryotic cell metabolism.
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Affiliation(s)
- Easun Arunachalam
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Felix C. Keber
- Lewis-Sigler Institute for Integrative Genomics
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Richard C. Law
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Chirag K. Kumar
- Lewis-Sigler Institute for Integrative Genomics
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Yihui Shen
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Junyoung O. Park
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Martin Wühr
- Lewis-Sigler Institute for Integrative Genomics
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Daniel J. Needleman
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Center for Computational Biology, Flatiron Institute, New York, NY, USA
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3
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Frese AN, Mariossi A, Levine MS, Wühr M. Quantitative proteome dynamics across embryogenesis in a model chordate. iScience 2024; 27:109355. [PMID: 38510129 PMCID: PMC10951915 DOI: 10.1016/j.isci.2024.109355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 12/11/2023] [Accepted: 02/23/2024] [Indexed: 03/22/2024] Open
Abstract
The evolution of gene expression programs underlying the development of vertebrates remains poorly characterized. Here, we present a comprehensive proteome atlas of the model chordate Ciona, covering eight developmental stages and ∼7,000 translated genes, accompanied by a multi-omics analysis of co-evolution with the vertebrate Xenopus. Quantitative proteome comparisons argue against the widely held hourglass model, based solely on transcriptomic profiles, whereby peak conservation is observed during mid-developmental stages. Our analysis reveals maximal divergence at these stages, particularly gastrulation and neurulation. Together, our work provides a valuable resource for evaluating conservation and divergence of multi-omics profiles underlying the diversification of vertebrates.
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Affiliation(s)
- Alexander N. Frese
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Andrea Mariossi
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Michael S. Levine
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Martin Wühr
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
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4
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Shen Y, Dinh HV, Cruz ER, Chen Z, Bartman CR, Xiao T, Call CM, Ryseck RP, Pratas J, Weilandt D, Baron H, Subramanian A, Fatma Z, Wu ZY, Dwaraknath S, Hendry JI, Tran VG, Yang L, Yoshikuni Y, Zhao H, Maranas CD, Wühr M, Rabinowitz JD. Mitochondrial ATP generation is more proteome efficient than glycolysis. Nat Chem Biol 2024:10.1038/s41589-024-01571-y. [PMID: 38448734 DOI: 10.1038/s41589-024-01571-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 02/05/2024] [Indexed: 03/08/2024]
Abstract
Metabolic efficiency profoundly influences organismal fitness. Nonphotosynthetic organisms, from yeast to mammals, derive usable energy primarily through glycolysis and respiration. Although respiration is more energy efficient, some cells favor glycolysis even when oxygen is available (aerobic glycolysis, Warburg effect). A leading explanation is that glycolysis is more efficient in terms of ATP production per unit mass of protein (that is, faster). Through quantitative flux analysis and proteomics, we find, however, that mitochondrial respiration is actually more proteome efficient than aerobic glycolysis. This is shown across yeast strains, T cells, cancer cells, and tissues and tumors in vivo. Instead of aerobic glycolysis being valuable for fast ATP production, it correlates with high glycolytic protein expression, which promotes hypoxic growth. Aerobic glycolytic yeasts do not excel at aerobic growth but outgrow respiratory cells during oxygen limitation. We accordingly propose that aerobic glycolysis emerges from cells maintaining a proteome conducive to both aerobic and hypoxic growth.
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Affiliation(s)
- Yihui Shen
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Hoang V Dinh
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Edward R Cruz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Zihong Chen
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton Branch, Princeton, NJ, USA
| | - Caroline R Bartman
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton Branch, Princeton, NJ, USA
| | - Tianxia Xiao
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Catherine M Call
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Rolf-Peter Ryseck
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Jimmy Pratas
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Daniel Weilandt
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Heide Baron
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Arjuna Subramanian
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Zia Fatma
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Zong-Yen Wu
- US Department of Energy Joint Genome Institute and Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Sudharsan Dwaraknath
- US Department of Energy Joint Genome Institute and Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - John I Hendry
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Vinh G Tran
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Lifeng Yang
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Yasuo Yoshikuni
- US Department of Energy Joint Genome Institute and Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Huimin Zhao
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Costas D Maranas
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Martin Wühr
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
| | - Joshua D Rabinowitz
- Department of Chemistry, Princeton University, Princeton, NJ, USA.
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
- Ludwig Institute for Cancer Research, Princeton Branch, Princeton, NJ, USA.
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5
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Keber FC, Nguyen T, Mariossi A, Brangwynne CP, Wühr M. Evidence for widespread cytoplasmic structuring into mesoscale condensates. Nat Cell Biol 2024; 26:346-352. [PMID: 38424273 PMCID: PMC10981939 DOI: 10.1038/s41556-024-01363-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 01/23/2024] [Indexed: 03/02/2024]
Abstract
Compartmentalization is an essential feature of eukaryotic life and is achieved both via membrane-bound organelles, such as mitochondria, and membrane-less biomolecular condensates, such as the nucleolus. Known biomolecular condensates typically exhibit liquid-like properties and are visualized by microscopy on the scale of ~1 µm (refs. 1,2). They have been studied mostly by microscopy, examining select individual proteins. So far, several dozen biomolecular condensates are known, serving a multitude of functions, for example, in the regulation of transcription3, RNA processing4 or signalling5,6, and their malfunction can cause diseases7,8. However, it remains unclear to what extent biomolecular condensates are utilized in cellular organization and at what length scale they typically form. Here we examine native cytoplasm from Xenopus egg extract on a global scale with quantitative proteomics, filtration, size exclusion and dilution experiments. These assays reveal that at least 18% of the proteome is organized into mesoscale biomolecular condensates at the scale of ~100 nm and appear to be stabilized by RNA or gelation. We confirmed mesoscale sizes via imaging below the diffraction limit by investigating protein permeation into porous substrates with defined pore sizes. Our results show that eukaryotic cytoplasm organizes extensively via biomolecular condensates, but at surprisingly short length scales.
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Affiliation(s)
- Felix C Keber
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Thao Nguyen
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Andrea Mariossi
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ, USA.
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ, USA.
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
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6
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Kafri M, Patena W, Martin L, Wang L, Gomer G, Ergun SL, Sirkejyan AK, Goh A, Wilson AT, Gavrilenko SE, Breker M, Roichman A, McWhite CD, Rabinowitz JD, Cross FR, Wühr M, Jonikas MC. Systematic identification and characterization of genes in the regulation and biogenesis of photosynthetic machinery. Cell 2023; 186:5638-5655.e25. [PMID: 38065083 PMCID: PMC10760936 DOI: 10.1016/j.cell.2023.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 08/03/2023] [Accepted: 11/03/2023] [Indexed: 12/18/2023]
Abstract
Photosynthesis is central to food production and the Earth's biogeochemistry, yet the molecular basis for its regulation remains poorly understood. Here, using high-throughput genetics in the model eukaryotic alga Chlamydomonas reinhardtii, we identify with high confidence (false discovery rate [FDR] < 0.11) 70 poorly characterized genes required for photosynthesis. We then enable the functional characterization of these genes by providing a resource of proteomes of mutant strains, each lacking one of these genes. The data allow assignment of 34 genes to the biogenesis or regulation of one or more specific photosynthetic complexes. Further analysis uncovers biogenesis/regulatory roles for at least seven proteins, including five photosystem I mRNA maturation factors, the chloroplast translation factor MTF1, and the master regulator PMR1, which regulates chloroplast genes via nuclear-expressed factors. Our work provides a rich resource identifying regulatory and functional genes and placing them into pathways, thereby opening the door to a system-level understanding of photosynthesis.
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Affiliation(s)
- Moshe Kafri
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Weronika Patena
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Lance Martin
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Lianyong Wang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Gillian Gomer
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sabrina L Ergun
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA
| | - Arthur K Sirkejyan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Audrey Goh
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Alexandra T Wilson
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sophia E Gavrilenko
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Michal Breker
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York, NY 10021, USA
| | - Asael Roichman
- Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Claire D McWhite
- Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Frederick R Cross
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York, NY 10021, USA
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics and Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Martin C Jonikas
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton, NJ 08544, USA.
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7
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Bartman CR, Weilandt DR, Shen Y, Lee WD, Han Y, TeSlaa T, Jankowski CSR, Samarah L, Park NR, da Silva-Diz V, Aleksandrova M, Gultekin Y, Marishta A, Wang L, Yang L, Roichman A, Bhatt V, Lan T, Hu Z, Xing X, Lu W, Davidson S, Wühr M, Vander Heiden MG, Herranz D, Guo JY, Kang Y, Rabinowitz JD. Slow TCA flux and ATP production in primary solid tumours but not metastases. Nature 2023; 614:349-357. [PMID: 36725930 PMCID: PMC10288502 DOI: 10.1038/s41586-022-05661-6] [Citation(s) in RCA: 103] [Impact Index Per Article: 103.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/14/2022] [Indexed: 02/03/2023]
Abstract
Tissues derive ATP from two pathways-glycolysis and the tricarboxylic acid (TCA) cycle coupled to the electron transport chain. Most energy in mammals is produced via TCA metabolism1. In tumours, however, the absolute rates of these pathways remain unclear. Here we optimize tracer infusion approaches to measure the rates of glycolysis and the TCA cycle in healthy mouse tissues, Kras-mutant solid tumours, metastases and leukaemia. Then, given the rates of these two pathways, we calculate total ATP synthesis rates. We find that TCA cycle flux is suppressed in all five primary solid tumour models examined and is increased in lung metastases of breast cancer relative to primary orthotopic tumours. As expected, glycolysis flux is increased in tumours compared with healthy tissues (the Warburg effect2,3), but this increase is insufficient to compensate for low TCA flux in terms of ATP production. Thus, instead of being hypermetabolic, as commonly assumed, solid tumours generally produce ATP at a slower than normal rate. In mouse pancreatic cancer, this is accommodated by the downregulation of protein synthesis, one of this tissue's major energy costs. We propose that, as solid tumours develop, cancer cells shed energetically expensive tissue-specific functions, enabling uncontrolled growth despite a limited ability to produce ATP.
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Affiliation(s)
- Caroline R Bartman
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Daniel R Weilandt
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Yihui Shen
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Won Dong Lee
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Yujiao Han
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Tara TeSlaa
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
| | - Connor S R Jankowski
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Laith Samarah
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Noel R Park
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | | | - Maya Aleksandrova
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Yetis Gultekin
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Boston, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Boston, MA, USA
| | - Argit Marishta
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Lin Wang
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Lifeng Yang
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Shanghai, China
| | - Asael Roichman
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Vrushank Bhatt
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Taijin Lan
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Zhixian Hu
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | - Xi Xing
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Wenyun Lu
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
| | - Shawn Davidson
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Martin Wühr
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Matthew G Vander Heiden
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Boston, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Boston, MA, USA
| | - Daniel Herranz
- Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ, USA
| | | | - Yibin Kang
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Joshua D Rabinowitz
- Department of Chemistry, Princeton University, Princeton, NJ, USA.
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ, USA.
- Ludwig Institute for Cancer Research, Princeton University, Princeton, NJ, USA.
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8
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Abstract
Deubiquitinases (DUBs) antagonize protein ubiquitination by removing ubiquitin from substrates. Identifying the physiological substrates of each DUB is critical for understanding DUB function and the principles that govern the specificity of this class of enzymes. Since multiple DUBs can act on the same substrate, it can be challenging to identify substrates using inactivating a single enzyme. Here, we outline a method that enables the identification of proteins whose stability depends on DUB activity and an approach to profile DUB specificity in Xenopus egg extract. By coupling broad DUB inhibition with quantitative proteomics, we circumvent DUB redundancy to identify DUB substrates. By adding back recombinant DUBs individually to the extract, we pinpoint DUBs sufficient to counteract proteasomal degradation of these newly identified substrates. We apply this method to Xenopus egg extract but suggest that it can also be adapted to other cell lysates.
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Affiliation(s)
- Valentina Rossio
- Department of Cell Biology, Blavatnik Institute at Harvard Medical School, Boston, MA, USA
| | - Joao A Paulo
- Department of Cell Biology, Blavatnik Institute at Harvard Medical School, Boston, MA, USA
| | - Randall W King
- Department of Cell Biology, Blavatnik Institute at Harvard Medical School, Boston, MA, USA.
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9
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Differential nuclear import sets the timing of protein access to the embryonic genome. Nat Commun 2022; 13:5887. [PMID: 36202846 PMCID: PMC9537182 DOI: 10.1038/s41467-022-33429-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 09/16/2022] [Indexed: 02/02/2023] Open
Abstract
The development of a fertilized egg to an embryo requires the proper temporal control of gene expression. During cell differentiation, timing is often controlled via cascades of transcription factors (TFs). However, in early development, transcription is often inactive, and many TF levels stay constant, suggesting that alternative mechanisms govern the observed rapid and ordered onset of gene expression. Here, we find that in early embryonic development access of maternally deposited nuclear proteins to the genome is temporally ordered via importin affinities, thereby timing the expression of downstream targets. We quantify changes in the nuclear proteome during early development and find that nuclear proteins, such as TFs and RNA polymerases, enter the nucleus sequentially. Moreover, we find that the timing of nuclear proteins' access to the genome corresponds to the timing of downstream gene activation. We show that the affinity of proteins to importin is a major determinant in the timing of protein entry into embryonic nuclei. Thus, we propose a mechanism by which embryos encode the timing of gene expression in early development via biochemical affinities. This process could be critical for embryos to organize themselves before deploying the regulatory cascades that control cell identities.
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10
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Zeng X, Xing X, Gupta M, Keber FC, Lopez JG, Lee YCJ, Roichman A, Wang L, Neinast MD, Donia MS, Wühr M, Jang C, Rabinowitz JD. Gut bacterial nutrient preferences quantified in vivo. Cell 2022; 185:3441-3456.e19. [PMID: 36055202 PMCID: PMC9450212 DOI: 10.1016/j.cell.2022.07.020] [Citation(s) in RCA: 62] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 06/02/2022] [Accepted: 07/21/2022] [Indexed: 12/12/2022]
Abstract
Great progress has been made in understanding gut microbiomes' products and their effects on health and disease. Less attention, however, has been given to the inputs that gut bacteria consume. Here, we quantitatively examine inputs and outputs of the mouse gut microbiome, using isotope tracing. The main input to microbial carbohydrate fermentation is dietary fiber and to branched-chain fatty acids and aromatic metabolites is dietary protein. In addition, circulating host lactate, 3-hydroxybutyrate, and urea (but not glucose or amino acids) feed the gut microbiome. To determine the nutrient preferences across bacteria, we traced into genus-specific bacterial protein sequences. We found systematic differences in nutrient use: most genera in the phylum Firmicutes prefer dietary protein, Bacteroides dietary fiber, and Akkermansia circulating host lactate. Such preferences correlate with microbiome composition changes in response to dietary modifications. Thus, diet shapes the microbiome by promoting the growth of bacteria that preferentially use the ingested nutrients.
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Affiliation(s)
- Xianfeng Zeng
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Xi Xing
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Meera Gupta
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Felix C Keber
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Jaime G Lopez
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Ying-Chiang J Lee
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Asael Roichman
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Lin Wang
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 5 Dong Dan San Tiao, Dongcheng District, Beijing 100005, China
| | - Michael D Neinast
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Mohamed S Donia
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.
| | - Cholsoon Jang
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA.
| | - Joshua D Rabinowitz
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Ludwig Institute for Cancer Research, Princeton Branch, Princeton University, Princeton, NJ 08544, USA.
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11
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Oocytes maintain ROS-free mitochondrial metabolism by suppressing complex I. Nature 2022; 607:756-761. [PMID: 35859172 PMCID: PMC9329100 DOI: 10.1038/s41586-022-04979-5] [Citation(s) in RCA: 85] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/15/2022] [Indexed: 12/23/2022]
Abstract
Oocytes form before birth and remain viable for several decades before fertilization1. Although poor oocyte quality accounts for most female fertility problems, little is known about how oocytes maintain cellular fitness, or why their quality eventually declines with age2. Reactive oxygen species (ROS) produced as by-products of mitochondrial activity are associated with lower rates of fertilization and embryo survival3-5. Yet, how healthy oocytes balance essential mitochondrial activity with the production of ROS is unknown. Here we show that oocytes evade ROS by remodelling the mitochondrial electron transport chain through elimination of complex I. Combining live-cell imaging and proteomics in human and Xenopus oocytes, we find that early oocytes exhibit greatly reduced levels of complex I. This is accompanied by a highly active mitochondrial unfolded protein response, which is indicative of an imbalanced electron transport chain. Biochemical and functional assays confirm that complex I is neither assembled nor active in early oocytes. Thus, we report a physiological cell type without complex I in animals. Our findings also clarify why patients with complex-I-related hereditary mitochondrial diseases do not experience subfertility. Complex I suppression represents an evolutionarily conserved strategy that allows longevity while maintaining biological activity in long-lived oocytes.
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12
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Baxi AB, Pade LR, Nemes P. Cell-Lineage Guided Mass Spectrometry Proteomics in the Developing (Frog) Embryo. J Vis Exp 2022:10.3791/63586. [PMID: 35532271 PMCID: PMC9513837 DOI: 10.3791/63586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023] Open
Abstract
Characterization of molecular events as cells give rise to tissues and organs raises a potential to better understand normal development and design efficient remedies for diseases. Technologies enabling accurate identification and quantification of diverse types and large numbers of proteins would provide still missing information on molecular mechanisms orchestrating tissue and organism development in space and time. Here, we present a mass spectrometry-based protocol that enables the measurement of thousands of proteins in identified cell lineages in Xenopus laevis (frog) embryos. The approach builds on reproducible cell-fate maps and established methods to identify, fluorescently label, track, and sample cells and their progeny (clones) from this model of vertebrate development. After collecting cellular contents using microsampling or isolating cells by dissection or fluorescence-activated cell sorting, proteins are extracted and processed for bottom-up proteomic analysis. Liquid chromatography and capillary electrophoresis are used to provide scalable separation for protein detection and quantification with high-resolution mass spectrometry (HRMS). Representative examples are provided for the proteomic characterization of neural-tissue fated cells. Cell-lineage-guided HRMS proteomics is adaptable to different tissues and organisms. It is sufficiently sensitive, specific, and quantitative to peer into the spatio-temporal dynamics of the proteome during vertebrate development.
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Affiliation(s)
- Aparna B Baxi
- Department of Chemistry & Biochemistry, University of Maryland; Department of Anatomy & Cell Biology, The George Washington University
| | - Leena R Pade
- Department of Chemistry & Biochemistry, University of Maryland
| | - Peter Nemes
- Department of Chemistry & Biochemistry, University of Maryland; Department of Anatomy & Cell Biology, The George Washington University;
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13
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Dai W, Li A, Yu NJ, Nguyen T, Leach RW, Wühr M, Kleiner RE. Activity-based RNA-modifying enzyme probing reveals DUS3L-mediated dihydrouridylation. Nat Chem Biol 2021; 17:1178-1187. [PMID: 34556860 PMCID: PMC8551019 DOI: 10.1038/s41589-021-00874-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 08/02/2021] [Indexed: 11/09/2022]
Abstract
Epitranscriptomic RNA modifications can regulate RNA activity; however, there remains a major gap in our understanding of the RNA chemistry present in biological systems. Here we develop RNA-mediated activity-based protein profiling (RNABPP), a chemoproteomic strategy that relies on metabolic RNA labeling, mRNA interactome capture and quantitative proteomics, to investigate RNA-modifying enzymes in human cells. RNABPP with 5-fluoropyrimidines allowed us to profile 5-methylcytidine (m5C) and 5-methyluridine (m5U) methyltransferases. Further, we uncover a new mechanism-based crosslink between 5-fluorouridine (5-FUrd)-modified RNA and the dihydrouridine synthase (DUS) homolog DUS3L. We investigate the mechanism of crosslinking and use quantitative nucleoside liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis and 5-FUrd-based crosslinking and immunoprecipitation (CLIP) sequencing to map DUS3L-dependent dihydrouridine (DHU) modifications across the transcriptome. Finally, we show that DUS3L-knockout (KO) cells have compromised protein translation rates and impaired cellular proliferation. Taken together, our work provides a general approach for profiling RNA-modifying enzyme activity in living cells and reveals new pathways for epitranscriptomic RNA regulation.
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Affiliation(s)
- Wei Dai
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA,These authors contributed equally
| | - Ang Li
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA,These authors contributed equally
| | - Nathan J. Yu
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Thao Nguyen
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA,Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Robert W. Leach
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Ralph E. Kleiner
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA,
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14
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Crapse J, Pappireddi N, Gupta M, Shvartsman SY, Wieschaus E, Wühr M. Evaluating the Arrhenius equation for developmental processes. Mol Syst Biol 2021; 17:e9895. [PMID: 34414660 PMCID: PMC8377445 DOI: 10.15252/msb.20209895] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 11/15/2022] Open
Abstract
The famous Arrhenius equation is well suited to describing the temperature dependence of chemical reactions but has also been used for complicated biological processes. Here, we evaluate how well the simple Arrhenius equation predicts complex multi-step biological processes, using frog and fruit fly embryogenesis as two canonical models. We find that the Arrhenius equation provides a good approximation for the temperature dependence of embryogenesis, even though individual developmental intervals scale differently with temperature. At low and high temperatures, however, we observed significant departures from idealized Arrhenius Law behavior. When we model multi-step reactions of idealized chemical networks, we are unable to generate comparable deviations from linearity. In contrast, we find the two enzymes GAPDH and β-galactosidase show non-linearity in the Arrhenius plot similar to our observations of embryonic development. Thus, we find that complex embryonic development can be well approximated by the simple Arrhenius equation regardless of non-uniform developmental scaling and propose that the observed departure from this law likely results more from non-idealized individual steps rather than from the complexity of the system.
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Affiliation(s)
- Joseph Crapse
- Undergraduate Integrated Science CurriculumPrinceton UniversityPrincetonNJUSA
- Department of Molecular BiologyPrinceton UniversityPrincetonNJUSA
- Lewis‐Sigler Institute for Integrative GenomicsPrinceton UniversityPrincetonNJUSA
| | - Nishant Pappireddi
- Department of Molecular BiologyPrinceton UniversityPrincetonNJUSA
- Lewis‐Sigler Institute for Integrative GenomicsPrinceton UniversityPrincetonNJUSA
| | - Meera Gupta
- Department of Molecular BiologyPrinceton UniversityPrincetonNJUSA
- Lewis‐Sigler Institute for Integrative GenomicsPrinceton UniversityPrincetonNJUSA
- Department of Chemical and Biological EngineeringPrinceton UniversityPrincetonNJUSA
| | - Stanislav Y Shvartsman
- Undergraduate Integrated Science CurriculumPrinceton UniversityPrincetonNJUSA
- Department of Molecular BiologyPrinceton UniversityPrincetonNJUSA
- Lewis‐Sigler Institute for Integrative GenomicsPrinceton UniversityPrincetonNJUSA
- Center for Computational BiologyFlatiron InstituteSimons FoundationNew YorkNYUSA
| | - Eric Wieschaus
- Undergraduate Integrated Science CurriculumPrinceton UniversityPrincetonNJUSA
- Department of Molecular BiologyPrinceton UniversityPrincetonNJUSA
- Lewis‐Sigler Institute for Integrative GenomicsPrinceton UniversityPrincetonNJUSA
| | - Martin Wühr
- Undergraduate Integrated Science CurriculumPrinceton UniversityPrincetonNJUSA
- Department of Molecular BiologyPrinceton UniversityPrincetonNJUSA
- Lewis‐Sigler Institute for Integrative GenomicsPrinceton UniversityPrincetonNJUSA
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15
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Johnson A, Stadlmeier M, Wühr M. TMTpro Complementary Ion Quantification Increases Plexing and Sensitivity for Accurate Multiplexed Proteomics at the MS2 Level. J Proteome Res 2021; 20:3043-3052. [PMID: 33929851 DOI: 10.1021/acs.jproteome.0c00813] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Multiplexed proteomics is a powerful tool to assay cell states in health and disease, but accurate quantification of relative protein changes is impaired by interference from co-isolated peptides. Interference can be reduced by using MS3-based quantification, but this reduces sensitivity and requires specialized instrumentation. An alternative approach is quantification by complementary ions, the balancer group-peptide conjugates, which allows accurate and precise multiplexed quantification at the MS2 level and is compatible with most proteomics instruments. However, complementary ions of the popular TMT-tag form inefficiently and multiplexing is limited to five channels. Here, we evaluate and optimize complementary ion quantification for the recently released TMTpro-tag, which increases complementary ion plexing capacity to eight channels (TMTproC). Furthermore, the beneficial fragmentation properties of TMTpro increase sensitivity for TMTproC, resulting in ∼65% more proteins quantified compared to TMTpro-MS3 and ∼18% more when compared to real-time-search TMTpro-MS3 (RTS-SPS-MS3). TMTproC quantification is more accurate than TMTpro-MS2 and even superior to RTS-SPS-MS3. We provide the software for quantifying TMTproC data as an executable that is compatible with the MaxQuant analysis pipeline. Thus, TMTproC advances multiplexed proteomics data quality and widens access to accurate multiplexed proteomics beyond laboratories with MS3-capable instrumentation.
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Affiliation(s)
- Alex Johnson
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, United States.,Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Michael Stadlmeier
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, United States
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, United States.,Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
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16
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Cao WX, Kabelitz S, Gupta M, Yeung E, Lin S, Rammelt C, Ihling C, Pekovic F, Low TCH, Siddiqui NU, Cheng MHK, Angers S, Smibert CA, Wühr M, Wahle E, Lipshitz HD. Precise Temporal Regulation of Post-transcriptional Repressors Is Required for an Orderly Drosophila Maternal-to-Zygotic Transition. Cell Rep 2021; 31:107783. [PMID: 32579915 PMCID: PMC7372737 DOI: 10.1016/j.celrep.2020.107783] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/06/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022] Open
Abstract
In animal embryos, the maternal-to-zygotic transition (MZT) hands developmental control from maternal to zygotic gene products. We show that the maternal proteome represents more than half of the protein-coding capacity of Drosophila melanogaster’s genome, and that 2% of this proteome is rapidly degraded during the MZT. Cleared proteins include the post-transcriptional repressors Cup, Trailer hitch (TRAL), Maternal expression at 31B (ME31B), and Smaug (SMG). Although the ubiquitin-proteasome system is necessary for clearance of these repressors, distinct E3 ligase complexes target them: the C-terminal to Lis1 Homology (CTLH) complex targets Cup, TRAL, and ME31B for degradation early in the MZT and the Skp/Cullin/F-box-containing (SCF) complex targets SMG at the end of the MZT. Deleting the C-terminal 233 amino acids of SMG abrogates F-box protein interaction and confers immunity to degradation. Persistent SMG downregulates zygotic re-expression of mRNAs whose maternal contribution is degraded by SMG. Thus, clearance of SMG permits an orderly MZT. Cao et al. show that 2% of the proteome is degraded in early Drosophila embryos, including a repressive ribonucleoprotein complex. Two E3 ubiquitin ligases separately act on distinct components of this complex to phase their clearance. Failure to degrade a key component, the Smaug RNA-binding protein, disrupts an orderly maternal-to-zygotic transition.
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Affiliation(s)
- Wen Xi Cao
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Sarah Kabelitz
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany
| | - Meera Gupta
- Department of Molecular Biology and the Lewis-Sigler Institute, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Eyan Yeung
- Department of Molecular Biology and the Lewis-Sigler Institute, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Sichun Lin
- Department of Pharmaceutical Sciences, University of Toronto, 144 College Street, Toronto, ON M5S 3M2, Canada
| | - Christiane Rammelt
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany
| | - Christian Ihling
- Institute of Pharmacy and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany
| | - Filip Pekovic
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany
| | - Timothy C H Low
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Najeeb U Siddiqui
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Matthew H K Cheng
- Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Stephane Angers
- Department of Pharmaceutical Sciences, University of Toronto, 144 College Street, Toronto, ON M5S 3M2, Canada; Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Craig A Smibert
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Department of Biochemistry, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Martin Wühr
- Department of Molecular Biology and the Lewis-Sigler Institute, Princeton University, Washington Road, Princeton, NJ 08544, USA
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06099 Halle, Germany.
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada.
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17
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The gain-of-function allele bamA E470K bypasses the essential requirement for BamD in β-barrel outer membrane protein assembly. Proc Natl Acad Sci U S A 2020; 117:18737-18743. [PMID: 32675245 DOI: 10.1073/pnas.2007696117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The outer membrane (OM) of gram-negative bacteria confers innate resistance to toxins and antibiotics. Integral β-barrel outer membrane proteins (OMPs) function to establish and maintain the selective permeability of the OM. OMPs are assembled into the OM by the β-barrel assembly machine (BAM), which is composed of one OMP-BamA-and four lipoproteins-BamB, C, D, and E. BamB, C, and E can be removed individually with only minor effects on barrier function; however, depletion of either BamA or BamD causes a global defect in OMP assembly and results in cell death. We have identified a gain-of-function mutation, bamA E470K , that bypasses the requirement for BamD. Although bamD::kan bamA E470K cells exhibit growth and OM barrier defects, they assemble OMPs with surprising robustness. Our results demonstrate that BamD does not play a catalytic role in OMP assembly, but rather functions to regulate the activity of BamA.
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18
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Multi-Omic Analyses Provide Links between Low-Dose Antibiotic Treatment and Induction of Secondary Metabolism in Burkholderia thailandensis. mBio 2020; 11:mBio.03210-19. [PMID: 32098820 PMCID: PMC7042699 DOI: 10.1128/mbio.03210-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Low doses of antibiotics can trigger secondary metabolite biosynthesis in bacteria, but the underlying mechanisms are generally unknown. We sought to better understand this phenomenon by studying how the antibiotic trimethoprim activates the synthesis of the virulence factor malleilactone in Burkholderia thailandensis Using transcriptomics, quantitative multiplexed proteomics, and primary metabolomics, we systematically mapped the changes induced by trimethoprim. Surprisingly, even subinhibitory doses of the antibiotic resulted in broad transcriptional and translational alterations, with ∼8.5% of the transcriptome and ∼5% of the proteome up- or downregulated >4-fold. Follow-up studies with genetic-biochemical experiments showed that the induction of malleilactone synthesis can be sufficiently explained by the accumulation of methionine biosynthetic precursors, notably homoserine, as a result of inhibition of the folate pathway. Homoserine activated the malleilactone gene cluster via the transcriptional regulator MalR and gave rise to a secondary metabolome which was very similar to that generated by trimethoprim. Our work highlights the expansive changes that low-dose trimethoprim induces on bacterial physiology and provides insights into its stimulatory effect on secondary metabolism.IMPORTANCE The discovery of antibiotics ranks among the most significant accomplishments of the last century. Although the targets of nearly all clinical antibiotics are known, our understanding regarding their natural functions and the effects of subinhibitory concentrations is in its infancy. Stimulatory rather than inhibitory functions have been attributed to low-dose antibiotics. Among these, we previously found that antibiotics activate silent biosynthetic genes and thereby enhance the metabolic output of bacteria. The regulatory circuits underlying this phenomenon are unknown. We take a first step toward elucidating these circuits and show that low doses of trimethoprim (Tmp) have cell-wide effects on the saprophyte Burkholderia thailandensis Most importantly, inhibition of one-carbon metabolic processes by Tmp leads to an accumulation of homoserine, which induces the production of an otherwise silent cytotoxin via a LuxR-type transcriptional regulator. These results provide a starting point for uncovering the molecular basis of the hormetic effects of antibiotics.
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19
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Sim HJ, Yun S, Kim HE, Kwon KY, Kim GH, Yun S, Kim BG, Myung K, Park TJ, Kwon T. Simple Method To Characterize the Ciliary Proteome of Multiciliated Cells. J Proteome Res 2019; 19:391-400. [DOI: 10.1021/acs.jproteome.9b00589] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
| | | | | | | | - Gun-Hwa Kim
- Drug & Disease Target Group, Korea Basic Science Institute (KSBI), Cheongju-si, Chungcheongbuk-do 28119, Republic of Korea
- Tunneling Nanotube Research Center, Division of Life Science, Korea University, Seoul 02841, Republic of Korea
| | - Sungho Yun
- Drug & Disease Target Group, Korea Basic Science Institute (KSBI), Cheongju-si, Chungcheongbuk-do 28119, Republic of Korea
| | - Byung Gyu Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Tae Joo Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Taejoon Kwon
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
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20
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Peshkin L, Gupta M, Ryazanova L, Wühr M. Bayesian Confidence Intervals for Multiplexed Proteomics Integrate Ion-statistics with Peptide Quantification Concordance. Mol Cell Proteomics 2019; 18:2108-2120. [PMID: 31311848 PMCID: PMC6773559 DOI: 10.1074/mcp.tir119.001317] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 06/11/2019] [Indexed: 01/28/2023] Open
Abstract
Multiplexed proteomics has emerged as a powerful tool to measure relative protein expression levels across multiple conditions. The relative protein abundances are inferred by comparing the signals generated by isobaric tags, which encode the samples' origins. Intuitively, the trust associated with a protein measurement depends on the similarity of ratios from the protein's peptides and the signal-strength of these measurements. However, typically the average peptide ratio is reported as the estimate of relative protein abundance, which is only the most likely ratio with a very naive model. Moreover, there is no sense on the confidence in these measurements. Here, we present a mathematically rigorous approach that integrates peptide signal strengths and peptide-measurement agreement into an estimation of the true protein ratio and the associated confidence (BACIQ). The main advantages of BACIQ are: (1) It removes the need to threshold reported peptide signal based on an arbitrary cut-off, thereby reporting more measurements from a given experiment; (2) Confidence can be assigned without replicates; (3) For repeated experiments BACIQ provides confidence intervals for the union, not the intersection, of quantified proteins; (4) For repeated experiments, BACIQ confidence intervals are more predictive than confidence intervals based on protein measurement agreement. To demonstrate the power of BACIQ we reanalyzed previously published data on subcellular protein movement on treatment with an Exportin-1 inhibiting drug. We detect ∼2× more highly significant movers, down to subcellular localization changes of ∼1%. Thus, our method drastically increases the value obtainable from quantitative proteomics experiments, helping researchers to interpret their data and prioritize resources. To make our approach easily accessible we distribute it via a Python/Stan package.
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Affiliation(s)
- Leonid Peshkin
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115
| | - Meera Gupta
- Department of Molecular Biology & the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544; DOE Center for Advanced Bioenergy and Bioproducts Innovation, Princeton, NJ 08544
| | - Lillia Ryazanova
- Department of Molecular Biology & the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544; DOE Center for Advanced Bioenergy and Bioproducts Innovation, Princeton, NJ 08544
| | - Martin Wühr
- Department of Molecular Biology & the Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544; DOE Center for Advanced Bioenergy and Bioproducts Innovation, Princeton, NJ 08544.
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Saha-Shah A, Esmaeili M, Sidoli S, Hwang H, Yang J, Klein PS, Garcia BA. Single Cell Proteomics by Data-Independent Acquisition To Study Embryonic Asymmetry in Xenopus laevis. Anal Chem 2019; 91:8891-8899. [PMID: 31194517 PMCID: PMC6688503 DOI: 10.1021/acs.analchem.9b00327] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Techniques that allow single cell analysis are gaining widespread attention, and most of these studies utilize genomics-based approaches. While nanofluidic technologies have enabled mass spectrometric analysis of single cells, these measurements have been limited to metabolomics and lipidomic studies. Single cell proteomics has the potential to improve our understanding of intercellular heterogeneity. However, this approach has faced challenges including limited sample availability, as well as a requirement of highly sensitive methods for sample collection, cleanup, and detection. We present a technique to overcome these limitations by combining a micropipette (pulled glass capillary) based sample collection strategy with offline sample preparation and nanoLC-MS/MS to analyze proteins through a bottom-up proteomic strategy. This study explores two types of proteomics data acquisition strategies namely data-dependent (DDA) and data-independent acquisition (DIA). Results from the study indicate DIA to be more sensitive enabling analysis of >1600 proteins from ∼130 μm Xenopus laevis embryonic cells containing <6 nL of cytoplasm. The method was found to be robust in obtaining reproducible protein quantifications from single cells spanning the 1-128-cell stages of development. Furthermore, we used micropipette sampling to study intercellular heterogeneity within cells in a single embryo and investigated embryonic asymmetry along both animal-vegetal and dorsal-ventral axes during early stages of development. Investigation of the animal-vegetal axis led to discovery of various asymmetrically distributed proteins along the animal-vegetal axis. We have further compared the hits found from our proteomic data sets with other studies and validated a few hits using an orthogonal imaging technique. This study forms the first report of vegetal enrichment of the germ plasm associated protein DDX4/VASA in Xenopus embyos. Overall, the method and data presented here holds promise to enable important leads in developmental biology.
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Affiliation(s)
- Anumita Saha-Shah
- Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Melody Esmaeili
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Simone Sidoli
- Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Hyojeong Hwang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, 3411 Veterinary Medicine Basic Sciences Building, Urbana, IL 61802, USA
| | - Jing Yang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, 3411 Veterinary Medicine Basic Sciences Building, Urbana, IL 61802, USA
| | - Peter S. Klein
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Medicine (Hematology-Oncology), Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Benjamin A. Garcia
- Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
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22
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Hart EM, Gupta M, Wühr M, Silhavy TJ. The Synthetic Phenotype of Δ bamB Δ bamE Double Mutants Results from a Lethal Jamming of the Bam Complex by the Lipoprotein RcsF. mBio 2019; 10:e00662-19. [PMID: 31113901 PMCID: PMC6529638 DOI: 10.1128/mbio.00662-19] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/16/2019] [Indexed: 01/23/2023] Open
Abstract
The selective permeability of the Gram-negative outer membrane (OM) is maintained by integral β-barrel outer membrane proteins (OMPs). The heteropentomeric β-barrel assembly machine (Bam) folds and inserts OMPs into the OM. Coordination of the essential proteins BamA and BamD is critical for OMP assembly and therefore the viability of the cell. The role of the nonessential lipoproteins BamBCE has yet to be characterized; however, genetic evidence suggests that they have nonoverlapping roles in OMP assembly. In this work, we quantify changes of the proteome in the conditional lethal ΔbamB ΔbamE double mutant. We show that cells lacking BamB and BamE have a global OMP defect that is a result of a lethal obstruction of an assembly-competent Bam complex by the lipoprotein RcsF. RcsF is a stress-sensing lipoprotein that is threaded through the lumen of abundant β-barrel OMPs by the Bam complex to expose the amino terminus on the cell surface. We demonstrate that simply removing this lipoprotein corrects the severe OMP assembly defect of the double mutant nearly as efficiently as a previously isolated suppressor mutation in bamA We propose that BamB and BamE play crucial, nonoverlapping roles to coordinate the activities of BamA and BamD during OMP biogenesis.IMPORTANCE Protein assembly into lipid bilayers is an essential process that ensures the viability of diverse organisms. In Gram-negative bacteria, the heteropentomeric β-barrel assembly machine (Bam) folds and inserts proteins into the outer membrane. Due to its essentiality, outer membrane protein (OMP) assembly by the Bam complex is an attractive target for antibiotic development. Here, we show that the conditional lethal phenotype of a mutant lacking two of the three nonessential lipoproteins, BamB and BamE, is caused by lethal jamming of the stripped-down Bam complex by a normally surface-exposed lipoprotein, RcsF. The heterotrimeric Bam complex (BamA, BamD, BamC) is nearly as efficient as the wild-type complex in OMP assembly if RcsF is removed. Our study highlights the importance of BamB and BamE in regulating the interaction between BamA and BamD and expands our understanding of the role of the Bam complex in outer membrane biogenesis.
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Affiliation(s)
- Elizabeth M Hart
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Meera Gupta
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Thomas J Silhavy
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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23
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Tye BW, Commins N, Ryazanova LV, Wühr M, Springer M, Pincus D, Churchman LS. Proteotoxicity from aberrant ribosome biogenesis compromises cell fitness. eLife 2019; 8:43002. [PMID: 30843788 PMCID: PMC6453566 DOI: 10.7554/elife.43002] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 03/06/2019] [Indexed: 12/31/2022] Open
Abstract
To achieve maximal growth, cells must manage a massive economy of ribosomal proteins (r-proteins) and RNAs (rRNAs) to produce thousands of ribosomes every minute. Although ribosomes are essential in all cells, natural disruptions to ribosome biogenesis lead to heterogeneous phenotypes. Here, we model these perturbations in Saccharomyces cerevisiae and show that challenges to ribosome biogenesis result in acute loss of proteostasis. Imbalances in the synthesis of r-proteins and rRNAs lead to the rapid aggregation of newly synthesized orphan r-proteins and compromise essential cellular processes, which cells alleviate by activating proteostasis genes. Exogenously bolstering the proteostasis network increases cellular fitness in the face of challenges to ribosome assembly, demonstrating the direct contribution of orphan r-proteins to cellular phenotypes. We propose that ribosome assembly is a key vulnerability of proteostasis maintenance in proliferating cells that may be compromised by diverse genetic, environmental, and xenobiotic perturbations that generate orphan r-proteins. Cells are made up of thousands of different proteins that perform unique roles required for life. To create all of these proteins, cells use machines called ribosomes that are partly formed of elements known as r-proteins. When cells grow and divide, the ribosomes have to make copies of themselves through a process called ribosome biogenesis. Although all cells need ribosomes, certain types of cells are especially sensitive to events that interfere with ribosome biogenesis. For example, patients that have mutations in genes needed for ribosome biogenesis produce fewer red blood cells, but their other cells and tissues are mostly healthy. It is not clear why some cells are more sensitive than others. Ribosome biogenesis is very similar between different organisms, so researchers often use budding yeast as a model to study the process. Here, Tye et al. used genetic and chemical tools to interfere with ribosome biogenesis on short time scales, which made it possible to detect early on what was going wrong in the cells. The experiments found that when ribosome biogenesis was disrupted, r-proteins that were waiting to be assembled into ribosomes quickly stuck to one another and formed clumps that reduced the ability of the yeast cells to grow. The cells responded by switching on a protein called Hsf1, which restored their ability to grow. Yeast cells that were growing quickly, and therefore making more ribosomes, were more sensitive to abnormal ribosome biogenesis than slow-growing cells. These results indicate that how actively a cell is growing, and its ability to cope with r-proteins sticking together, may in part explain why certain cells are more vulnerable to events that interfere with ribosome biogenesis. Since human cells also have Hsf1, future experiments could investigate whether turning it on might also protect fast-growing human cells from such events.
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Affiliation(s)
- Blake W Tye
- Department of Genetics, Harvard Medical School, Boston, United States.,Program in Chemical Biology, Harvard University, Cambridge, United States
| | - Nicoletta Commins
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Lillia V Ryazanova
- Department of Molecular Biology, Princeton University, Princeton, United States.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States
| | - Martin Wühr
- Department of Molecular Biology, Princeton University, Princeton, United States.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States
| | - Michael Springer
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - David Pincus
- Whitehead Institute for Biomedical Research, Cambridge, United States.,Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States.,Center for Physics of Evolving Systems, University of Chicago, Chicago, United States
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24
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Affiliation(s)
- Albert B. Arul
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Renã A. S. Robinson
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Vanderbilt Memory & Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, Tennessee 37212, United States
- Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37235, United States
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