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Sasazawa M, Tomares DT, Childers WS, Saurabh S. Biomolecular condensates as stress sensors and modulators of bacterial signaling. PLoS Pathog 2024; 20:e1012413. [PMID: 39146259 PMCID: PMC11326607 DOI: 10.1371/journal.ppat.1012413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024] Open
Abstract
Microbes exhibit remarkable adaptability to environmental fluctuations. Signaling mechanisms, such as two-component systems and secondary messengers, have long been recognized as critical for sensing and responding to environmental cues. However, recent research has illuminated the potential of a physical adaptation mechanism in signaling-phase separation, which may represent a ubiquitous mechanism for compartmentalizing biochemistry within the cytoplasm in the context of bacteria that frequently lack membrane-bound organelles. This review considers the broader prospect that phase separation may play critical roles as rapid stress sensing and response mechanisms within pathogens. It is well established that weak multivalent interactions between disordered regions, coiled-coils, and other structured domains can form condensates via phase separation and be regulated by specific environmental parameters in some cases. The process of phase separation itself acts as a responsive sensor, influenced by changes in protein concentration, posttranslational modifications, temperature, salts, pH, and oxidative stresses. This environmentally triggered phase separation can, in turn, regulate the functions of recruited biomolecules, providing a rapid response to stressful conditions. As examples, we describe biochemical pathways organized by condensates that are essential for cell physiology and exhibit signaling features. These include proteins that organize and modify the chromosome (Dps, Hu, SSB), regulate the decay, and modification of RNA (RNase E, Hfq, Rho, RNA polymerase), those involved in signal transduction (PopZ, PodJ, and SpmX) and stress response (aggresomes and polyphosphate granules). We also summarize the potential of proteins within pathogens to function as condensates and the potential and challenges in targeting biomolecular condensates for next-generation antimicrobial therapeutics. Together, this review illuminates the emerging significance of biomolecular condensates in microbial signaling, stress responses, and regulation of cell physiology and provides a framework for microbiologists to consider the function of biomolecular condensates in microbial adaptation and response to diverse environmental conditions.
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Affiliation(s)
- Moeka Sasazawa
- Department of Chemistry, New York University, New York, New York, United States of America
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Saumya Saurabh
- Department of Chemistry, New York University, New York, New York, United States of America
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Nandana V, Al-Husini N, Vaishnav A, Dilrangi KH, Schrader JM. Caulobacter crescentus RNase E condensation contributes to autoregulation and fitness. Mol Biol Cell 2024; 35:ar104. [PMID: 38865176 PMCID: PMC11321048 DOI: 10.1091/mbc.e23-12-0493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/29/2024] [Accepted: 06/03/2024] [Indexed: 06/13/2024] Open
Abstract
RNase E is the most common RNA decay nuclease in bacteria, setting the global mRNA decay rate and scaffolding formation of the RNA degradosome complex and BR-bodies. To properly set the global mRNA decay rate, RNase E from Escherichia coli and neighboring γ-proteobacteria were found to autoregulate RNase E levels via the decay of its mRNA's 5' untranslated region (UTR). While the 5' UTR is absent from other groups of bacteria in the Rfam database, we identified that the α-proteobacterium Caulobacter crescentus RNase E contains a similar 5' UTR structure that promotes RNase E autoregulation. In both bacteria, the C-terminal intrinsically disordered region (IDR) of RNase E is required for proper autoregulation to occur, and this IDR is also necessary and sufficient for RNase E to phase-separate, generating BR-bodies. Using in vitro purified RNase E, we find that the IDR's ability to promote phase separation correlates with enhanced 5' UTR cleavage, suggesting that phase separation of RNase E with the 5' UTR enhances autoregulation. Finally, using growth competition experiments, we find that a strain capable of autoregulation rapidly outcompetes a strain with a 5' UTR mutation that cannot autoregulate, suggesting autoregulation promotes optimal cellular fitness.
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Affiliation(s)
- Vidhyadhar Nandana
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202
| | - Nadra Al-Husini
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202
| | - Arti Vaishnav
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202
| | | | - Jared M. Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202
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3
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Wang L, Zhou W. Phase separation as a new form of regulation in innate immunity. Mol Cell 2024; 84:2410-2422. [PMID: 38936362 DOI: 10.1016/j.molcel.2024.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/22/2024] [Accepted: 06/05/2024] [Indexed: 06/29/2024]
Abstract
Innate immunity is essential for the host against pathogens, cancer, and autoimmunity. The innate immune system encodes many sensor, adaptor, and effector proteins and relies on the assembly of higher-order signaling complexes to activate immune defense. Recent evidence demonstrates that many of the core complexes involved in innate immunity are organized as liquid-like condensates through a mechanism known as phase separation. Here, we discuss phase-separated condensates and their diverse functions. We compare the biochemical, structural, and mechanistic details of solid and liquid-like assemblies to explore the role of phase separation in innate immunity. We summarize the emerging evidence for the hypothesis that phase separation is a conserved mechanism that controls immune responses across the tree of life. The discovery of phase separation in innate immunity provides a new foundation to explain the rules that govern immune system activation and will enable the development of therapeutics to treat immune-related diseases properly.
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Affiliation(s)
- Lei Wang
- Department of Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wen Zhou
- Shenzhen Key Laboratory of Biomolecular Assembling and Regulation, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China; Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China.
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Taylor KE, Miller LG, Contreras LM. RNA-binding proteins that preferentially interact with 8-oxoG-modified RNAs: our current understanding. Biochem Soc Trans 2024; 52:111-122. [PMID: 38174726 DOI: 10.1042/bst20230254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024]
Abstract
Cells encounter a variety of stresses throughout their lifetimes. Oxidative stress can occur via a myriad of factors, including exposure to chemical toxins or UV light. Importantly, these stressors induce chemical changes (e.g. chemical modifications) to biomolecules, such as RNA. Commonly, guanine is oxidized to form 8-oxo-7,8-hydroxyguanine (8-oxoG) and this modification can disrupt a plethora of cellular processes including messenger RNA translation and stability. Polynucleotide phosphorylase (PNPase), heterogeneous nuclear ribonucleoprotein D (HNRPD/Auf1), poly(C)-binding protein (PCBP1/HNRNP E1), and Y-box binding protein 1 (YB-1) have been identified as four RNA-binding proteins that preferentially bind 8-oxoG-modified RNA over unmodified RNA. All four proteins are native to humans and PNPase is additionally found in bacteria. Additionally, under oxidative stress, cell survival declines in mutants that lack PNPase, Auf1, or PCBP1, suggesting they are critical to the oxidative stress response. This mini-review captures the current understanding of the PNPase, HNRPD/Auf1, PCBP1, and YB-1 proteins and the mechanism that has been outlined so far by which they recognize and interact with 8-oxoG-modified RNAs.
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Affiliation(s)
- Kathleen E Taylor
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, USA
| | - Lucas G Miller
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, USA
| | - Lydia M Contreras
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, USA
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
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5
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Monterroso B, Margolin W, Boersma AJ, Rivas G, Poolman B, Zorrilla S. Macromolecular Crowding, Phase Separation, and Homeostasis in the Orchestration of Bacterial Cellular Functions. Chem Rev 2024; 124:1899-1949. [PMID: 38331392 PMCID: PMC10906006 DOI: 10.1021/acs.chemrev.3c00622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/01/2023] [Accepted: 01/10/2024] [Indexed: 02/10/2024]
Abstract
Macromolecular crowding affects the activity of proteins and functional macromolecular complexes in all cells, including bacteria. Crowding, together with physicochemical parameters such as pH, ionic strength, and the energy status, influences the structure of the cytoplasm and thereby indirectly macromolecular function. Notably, crowding also promotes the formation of biomolecular condensates by phase separation, initially identified in eukaryotic cells but more recently discovered to play key functions in bacteria. Bacterial cells require a variety of mechanisms to maintain physicochemical homeostasis, in particular in environments with fluctuating conditions, and the formation of biomolecular condensates is emerging as one such mechanism. In this work, we connect physicochemical homeostasis and macromolecular crowding with the formation and function of biomolecular condensates in the bacterial cell and compare the supramolecular structures found in bacteria with those of eukaryotic cells. We focus on the effects of crowding and phase separation on the control of bacterial chromosome replication, segregation, and cell division, and we discuss the contribution of biomolecular condensates to bacterial cell fitness and adaptation to environmental stress.
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Affiliation(s)
- Begoña Monterroso
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
| | - William Margolin
- Department
of Microbiology and Molecular Genetics, McGovern Medical School, UTHealth-Houston, Houston, Texas 77030, United States
| | - Arnold J. Boersma
- Cellular
Protein Chemistry, Bijvoet Centre for Biomolecular Research, Faculty
of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Germán Rivas
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
| | - Bert Poolman
- Department
of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Silvia Zorrilla
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
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Nandana V, Rathnayaka-Mudiyanselage IW, Muthunayake NS, Hatami A, Mousseau CB, Ortiz-Rodríguez LA, Vaishnav J, Collins M, Gega A, Mallikaarachchi KS, Yassine H, Ghosh A, Biteen JS, Zhu Y, Champion MM, Childers WS, Schrader JM. The BR-body proteome contains a complex network of protein-protein and protein-RNA interactions. Cell Rep 2023; 42:113229. [PMID: 37815915 PMCID: PMC10842194 DOI: 10.1016/j.celrep.2023.113229] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 07/16/2023] [Accepted: 09/22/2023] [Indexed: 10/12/2023] Open
Abstract
Bacterial ribonucleoprotein bodies (BR-bodies) are non-membrane-bound structures that facilitate mRNA decay by concentrating mRNA substrates with RNase E and the associated RNA degradosome machinery. However, the full complement of proteins enriched in BR-bodies has not been defined. Here, we define the protein components of BR-bodies through enrichment of the bodies followed by mass spectrometry-based proteomic analysis. We find 111 BR-body-enriched proteins showing that BR-bodies are more complex than previously assumed. We identify five BR-body-enriched proteins that undergo RNA-dependent phase separation in vitro with a complex network of condensate mixing. We observe that some RNP condensates co-assemble with preferred directionality, suggesting that RNA may be trafficked through RNP condensates in an ordered manner to facilitate mRNA processing/decay, and that some BR-body-associated proteins have the capacity to dissolve the condensate. Altogether, these results suggest that a complex network of protein-protein and protein-RNA interactions controls BR-body phase separation and RNA processing.
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Affiliation(s)
- Vidhyadhar Nandana
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Imalka W Rathnayaka-Mudiyanselage
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA; Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | | | - Ali Hatami
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - C Bruce Mousseau
- Department of Chemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | | | - Jamuna Vaishnav
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - Michael Collins
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Alisa Gega
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | | | - Hadi Yassine
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Aishwarya Ghosh
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yingxi Zhu
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - Matthew M Champion
- Department of Chemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
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