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Boyd-Shiwarski CR, Shiwarski DJ, Subramanya AR. A New Phase for WNK Kinase Signaling Complexes as Biomolecular Condensates. Physiology (Bethesda) 2024; 39:0. [PMID: 38624245 DOI: 10.1152/physiol.00013.2024] [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: 02/22/2024] [Revised: 04/09/2024] [Accepted: 04/09/2024] [Indexed: 04/17/2024] Open
Abstract
The purpose of this review is to highlight transformative advances that have been made in the field of biomolecular condensates, with special emphasis on condensate material properties, physiology, and kinases, using the With-No-Lysine (WNK) kinases as a prototypical example. To convey how WNK kinases illustrate important concepts for biomolecular condensates, we start with a brief history, focus on defining features of biomolecular condensates, and delve into some examples of how condensates are implicated in cellular physiology (and pathophysiology). We then highlight how WNK kinases, through the action of "WNK droplets" that ubiquitously regulate intracellular volume and kidney-specific "WNK bodies" that are implicated in distal tubule salt reabsorption and potassium homeostasis, exemplify many of the defining features of condensates. Finally, this review addresses the controversies within this emerging field and questions to address.
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Affiliation(s)
- Cary R Boyd-Shiwarski
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Pittsburgh Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Daniel J Shiwarski
- Vascular Medicine Institute, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Arohan R Subramanya
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Pittsburgh Heart, Lung, Blood Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, United States
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2
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Paul MW, Aaron J, Wait E, Van Genderen RM, Tyagi A, Kabbech H, Smal I, Chew TL, Kanaar R, Wyman C. Distinct mobility patterns of BRCA2 molecules at DNA damage sites. Nucleic Acids Res 2024:gkae559. [PMID: 38953170 DOI: 10.1093/nar/gkae559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 06/10/2024] [Accepted: 06/18/2024] [Indexed: 07/03/2024] Open
Abstract
BRCA2 is an essential tumor suppressor protein involved in promoting faithful repair of DNA lesions. The activity of BRCA2 needs to be tuned precisely to be active when and where it is needed. Here, we quantified the spatio-temporal dynamics of BRCA2 in living cells using aberration-corrected multifocal microscopy (acMFM). Using multicolor imaging to identify DNA damage sites, we were able to quantify its dynamic motion patterns in the nucleus and at DNA damage sites. While a large fraction of BRCA2 molecules localized near DNA damage sites appear immobile, an additional fraction of molecules exhibits subdiffusive motion, providing a potential mechanism to retain an increased number of molecules at DNA lesions. Super-resolution microscopy revealed inhomogeneous localization of BRCA2 relative to other DNA repair factors at sites of DNA damage. This suggests the presence of multiple nanoscale compartments in the chromatin surrounding the DNA lesion, which could play an important role in the contribution of BRCA2 to the regulation of the repair process.
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Affiliation(s)
- Maarten W Paul
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jesse Aaron
- Advanced Imaging Center, HHMI Janelia, Ashburn VA, USA
| | - Eric Wait
- Advanced Imaging Center, HHMI Janelia, Ashburn VA, USA
- Elephas Biosciences, Madison WI, USA
| | - Romano M Van Genderen
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Arti Tyagi
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Bionanoscience and Kavli Institute of Nanoscience Delft, Delft, University of Technology, Delft, The Netherlands
| | - Hélène Kabbech
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Ihor Smal
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
- Theme Biomedical Sciences, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | - Roland Kanaar
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Claire Wyman
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
- Department of Radiation Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
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3
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Purshouse K, Pollard SM, Bickmore WA. Imaging extrachromosomal DNA (ecDNA) in cancer. Histochem Cell Biol 2024; 162:53-64. [PMID: 38625562 PMCID: PMC7616135 DOI: 10.1007/s00418-024-02280-2] [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] [Accepted: 03/19/2024] [Indexed: 04/17/2024]
Abstract
Extrachromosomal DNA (ecDNA) are circular regions of DNA that are found in many cancers. They are an important means of oncogene amplification, and correlate with treatment resistance and poor prognosis. Consequently, there is great interest in exploring and targeting ecDNA vulnerabilities as potential new therapeutic targets for cancer treatment. However, the biological significance of ecDNA and their associated regulatory control remains unclear. Light microscopy has been a central tool in the identification and characterisation of ecDNA. In this review we describe the different cellular models available to study ecDNA, and the imaging tools used to characterise ecDNA and their regulation. The insights gained from quantitative imaging are discussed in comparison with genome sequencing and computational approaches. We suggest that there is a crucial need for ongoing innovation using imaging if we are to achieve a full understanding of the dynamic regulation and organisation of ecDNA and their role in tumourigenesis.
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Affiliation(s)
- Karin Purshouse
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
- Centre for Regenerative Medicine, Institute for Regeneration and Repair & Cancer Research UK Scotland Centre, University of Edinburgh, Edinburgh, UK
- Edinburgh Cancer Research UK Centre, University of Edinburgh, Edinburgh, UK
| | - Steven M Pollard
- Centre for Regenerative Medicine, Institute for Regeneration and Repair & Cancer Research UK Scotland Centre, University of Edinburgh, Edinburgh, UK
- Edinburgh Cancer Research UK Centre, University of Edinburgh, Edinburgh, UK
| | - Wendy A Bickmore
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK.
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4
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Barkley RJR, Crowley JC, Brodrick AJ, Zipfel WR, Parker JSL. Fluorescent protein tags affect the condensation properties of a phase-separating viral protein. Mol Biol Cell 2024; 35:ar100. [PMID: 38809580 PMCID: PMC11244164 DOI: 10.1091/mbc.e24-01-0013] [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: 01/16/2024] [Revised: 05/17/2024] [Accepted: 05/24/2024] [Indexed: 05/30/2024] Open
Abstract
Fluorescent protein (FP) tags are extensively used to visualize and characterize the properties of biomolecular condensates despite a lack of investigation into the effects of these tags on phase separation. Here, we characterized the dynamic properties of µNS, a viral protein hypothesized to undergo phase separation and the main component of mammalian orthoreovirus viral factories. Our interest in the sequence determinants and nucleation process of µNS phase separation led us to compare the size and density of condensates formed by FP::µNS to the untagged protein. We found an FP-dependent increase in droplet size and density, which suggests that FP tags can promote µNS condensation. To further assess the effect of FP tags on µNS droplet formation, we fused FP tags to µNS mutants to show that the tags could variably induce phase separation of otherwise noncondensing proteins. By comparing fluorescent constructs with untagged µNS, we identified mNeonGreen as the least artifactual FP tag that minimally perturbed µNS condensation. These results show that FP tags can promote phase separation and that some tags are more suitable for visualizing and characterizing biomolecular condensates with minimal experimental artifacts.
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Affiliation(s)
- Russell J. R. Barkley
- Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850
| | - Jack C. Crowley
- School of Applied and Engineering Physics, College of Engineering, Cornell University, Ithaca, NY 14850
| | - Andrew J. Brodrick
- Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850
| | - Warren R. Zipfel
- School of Applied and Engineering Physics, College of Engineering, Cornell University, Ithaca, NY 14850
- Meinig School of Biomedical Engineering, College of Engineering, Cornell University, Ithaca, NY 14850
| | - John S. L. Parker
- Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850
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5
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Benchorin G, Cho RJ, Li MJ, Molotkova N, Kohwi M. Dan forms condensates in neuroblasts and regulates nuclear architecture and progenitor competence in vivo. Nat Commun 2024; 15:5097. [PMID: 38877037 PMCID: PMC11178893 DOI: 10.1038/s41467-024-49326-6] [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: 01/22/2024] [Accepted: 05/30/2024] [Indexed: 06/16/2024] Open
Abstract
Genome organization is thought to underlie cell type specific gene expression, yet how it is regulated in progenitors to produce cellular diversity is unknown. In Drosophila, a developmentally-timed genome reorganization in neural progenitors terminates competence to produce early-born neurons. These events require downregulation of Distal antenna (Dan), part of the conserved pipsqueak DNA-binding superfamily. Here we find that Dan forms liquid-like condensates with high protein mobility, and whose size and subnuclear distribution are balanced with its DNA-binding. Further, we identify a LARKS domain, a structural motif associated with condensate-forming proteins. Deleting just 13 amino acids from LARKS abrogates Dan's ability to retain the early-born neural fate gene, hunchback, in the neuroblast nuclear interior and maintain competence in vivo. Conversely, domain-swapping with LARKS from known phase-separating proteins rescues Dan's effects on competence. Together, we provide in vivo evidence for condensate formation and the regulation of progenitor nuclear architecture underlying neuronal diversification.
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Affiliation(s)
- Gillie Benchorin
- Department of Biological Sciences, Columbia University, New York, NY, USA
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Richard Jangwon Cho
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University, New York, NY, USA
| | - Maggie Jiaqi Li
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University, New York, NY, USA
| | - Natalia Molotkova
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University, New York, NY, USA
| | - Minoree Kohwi
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
- Department of Neuroscience, Columbia University, New York, NY, USA.
- Kavli Institute for Brain Science, Columbia University, New York, NY, USA.
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6
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Milne TA. Chromatin and aberrant enhancer activity in KMT2A rearranged acute lymphoblastic leukemia. Curr Opin Genet Dev 2024; 86:102191. [PMID: 38579381 DOI: 10.1016/j.gde.2024.102191] [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: 12/18/2023] [Revised: 03/11/2024] [Accepted: 03/19/2024] [Indexed: 04/07/2024]
Abstract
To make a multicellular organism, genes need to be transcribed at the right developmental stages and in the right tissues. DNA sequences termed 'enhancers' are crucial to achieve this. Despite concerted efforts, the exact mechanisms of enhancer activity remain elusive. Mixed lineage leukemia (MLL or KMT2A) rearrangements (MLLr), commonly observed in cases of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia, produce novel in-frame fusion proteins. Recent work has shown that the MLL-AF4 fusion protein drives aberrant enhancer activity at key oncogenes in ALL, dependent on the continued presence of MLL-AF4 complex components. As well as providing some general insights into enhancer function, these observations may also provide an explanation for transcriptional heterogeneity observed in MLLr patients.
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Affiliation(s)
- Thomas A Milne
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, UK.
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Ebstrup E, Ansbøl J, Paez-Garcia A, Culp H, Chevalier J, Clemmens P, Coll NS, Moreno-Risueno MA, Rodriguez E. NBR1-mediated selective autophagy of ARF7 modulates root branching. EMBO Rep 2024; 25:2571-2591. [PMID: 38684906 PMCID: PMC11169494 DOI: 10.1038/s44319-024-00142-5] [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: 12/08/2023] [Revised: 04/05/2024] [Accepted: 04/10/2024] [Indexed: 05/02/2024] Open
Abstract
Auxin dictates root architecture via the Auxin Response Factor (ARF) family of transcription factors, which control lateral root (LR) formation. In Arabidopsis, ARF7 regulates the specification of prebranch sites (PBS) generating LRs through gene expression oscillations and plays a pivotal role during LR initiation. Despite the importance of ARF7 in this process, there is a surprising lack of knowledge about how ARF7 turnover is regulated and how this impacts root architecture. Here, we show that ARF7 accumulates in autophagy mutants and is degraded through NBR1-dependent selective autophagy. We demonstrate that the previously reported rhythmic changes to ARF7 abundance in roots are modulated via autophagy and might occur in other tissues. In addition, we show that the level of co-localization between ARF7 and autophagy markers oscillates and can be modulated by auxin to trigger ARF7 turnover. Furthermore, we observe that autophagy impairment prevents ARF7 oscillation and reduces both PBS establishment and LR formation. In conclusion, we report a novel role for autophagy during development, namely by enacting auxin-induced selective degradation of ARF7 to optimize periodic root branching.
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Affiliation(s)
- Elise Ebstrup
- Department of Biology, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Jeppe Ansbøl
- Department of Biology, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Ana Paez-Garcia
- Centro de Biotecnología y Genómica de Plantas (Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria-CSIC (INIA/CSIC)). Campus de Montegancedo, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Henry Culp
- Department of Biology, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Jonathan Chevalier
- Department of Biology, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Pauline Clemmens
- Department of Biology, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Núria S Coll
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Bellaterra, 08193, Spain
- Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, 08001, Spain
| | - Miguel A Moreno-Risueno
- Centro de Biotecnología y Genómica de Plantas (Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria-CSIC (INIA/CSIC)). Campus de Montegancedo, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Eleazar Rodriguez
- Department of Biology, University of Copenhagen, 2200, Copenhagen N, Denmark.
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Cai H, Zhao J, Zhang Q, Wu H, Sun Y, Guo F, Zhou Y, Qin G, Xia W, Zhao Y, Liang X, Yin S, Qin Y, Li D, Wu H, Ren D. Ubiquitin ligase TRIM15 promotes the progression of pancreatic cancer via the upregulation of the IGF2BP2-TLR4 axis. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167183. [PMID: 38657551 DOI: 10.1016/j.bbadis.2024.167183] [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: 11/30/2023] [Revised: 03/17/2024] [Accepted: 04/15/2024] [Indexed: 04/26/2024]
Abstract
BACKGROUND The tripartite motif family, predominantly characterized by its E3 ubiquitin ligase activities, is involved in various cellular processes including signal transduction, apoptosis and autophagy, protein quality control, immune regulation, and carcinogenesis. Tripartite Motif Containing 15 (TRIM15) plays an important role in melanoma progression through extracellular signal-regulated kinase activation; however, data on its role in pancreatic tumors remain lacking. We previously demonstrated that TRIM15 targeted lipid synthesis and metabolism in pancreatic cancer; however, other specific regulatory mechanisms remain elusive. METHODS We used transcriptomics and proteomics, conducted a series of phenotypic experiments, and used a mouse orthotopic transplantation model to study the specific mechanism of TRIM15 in pancreatic cancer in vitro and in vivo. RESULTS TRIM15 overexpression promoted the progression of pancreatic cancer by upregulating the toll-like receptor 4. The TRIM15 binding protein, IGF2BP2, could combine with TLR4 to inhibit its mRNA degradation. Furthermore, the ubiquitin level of IGF2BP2 was positively correlated with TRIM15. CONCLUSIONS TRIM15 could ubiquitinate IGF2BP2 to enhance the function of phase separation and the maintenance of mRNA stability of TLR4. TRIM15 is a potential therapeutic target against pancreatic cancer.
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Affiliation(s)
- Hongkun Cai
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Jingyuan Zhao
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Qiyue Zhang
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Heyu Wu
- Department of Operating Room, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Yan Sun
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Feng Guo
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Yingke Zhou
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Gengdu Qin
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Wentao Xia
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Yuhan Zhao
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Xueyi Liang
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Shilin Yin
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Yang Qin
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Dan Li
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Heshui Wu
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Dianyun Ren
- Department of Pancreatic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Sino-German Laboratory of Personalized Medicine for Pancreatic Cancer, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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9
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Mathias KM, Liu Y, Wan L. Dysregulation of transcriptional condensates in human disease: mechanisms, biological functions, and open questions. Curr Opin Genet Dev 2024; 86:102203. [PMID: 38788489 PMCID: PMC11162900 DOI: 10.1016/j.gde.2024.102203] [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: 10/30/2023] [Revised: 04/18/2024] [Accepted: 04/22/2024] [Indexed: 05/26/2024]
Abstract
Precise gene expression, crucial for normal development and health, depends on the co-ordinated assembly and function of various factors within the crowded nucleus. Recent evidence suggests that this process is in part regulated by mesoscale compartmentalization and concentration of transcriptional components within condensates, offering a new perspective on gene regulation. Dysregulation of transcriptional condensates is increasingly associated with diseases, indicating a potential role in pathogenesis. In this mini-review, we provide a concise overview of the current understanding of the formation and function of transcriptional condensates, with a specific focus on recent advances in their dysregulation and implications in diseases, notably cancer. We also address limitations in the field and highlight open questions for future research.
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Affiliation(s)
- Kaeli M Mathias
- Department of Cancer Biology and Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry Biophysics Chemical Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yiman Liu
- Department of Cancer Biology and Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Liling Wan
- Department of Cancer Biology and Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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10
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He J, Huo X, Pei G, Jia Z, Yan Y, Yu J, Qu H, Xie Y, Yuan J, Zheng Y, Hu Y, Shi M, You K, Li T, Ma T, Zhang MQ, Ding S, Li P, Li Y. Dual-role transcription factors stabilize intermediate expression levels. Cell 2024; 187:2746-2766.e25. [PMID: 38631355 DOI: 10.1016/j.cell.2024.03.023] [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: 06/09/2023] [Revised: 12/08/2023] [Accepted: 03/18/2024] [Indexed: 04/19/2024]
Abstract
Precise control of gene expression levels is essential for normal cell functions, yet how they are defined and tightly maintained, particularly at intermediate levels, remains elusive. Here, using a series of newly developed sequencing, imaging, and functional assays, we uncover a class of transcription factors with dual roles as activators and repressors, referred to as condensate-forming level-regulating dual-action transcription factors (TFs). They reduce high expression but increase low expression to achieve stable intermediate levels. Dual-action TFs directly exert activating and repressing functions via condensate-forming domains that compartmentalize core transcriptional unit selectively. Clinically relevant mutations in these domains, which are linked to a range of developmental disorders, impair condensate selectivity and dual-action TF activity. These results collectively address a fundamental question in expression regulation and demonstrate the potential of level-regulating dual-action TFs as powerful effectors for engineering controlled expression levels.
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Affiliation(s)
- Jinnan He
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Xiangru Huo
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Gaofeng Pei
- State Key Laboratory of Membrane Biology, Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China
| | - Zeran Jia
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Yiming Yan
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Jiawei Yu
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Haozhi Qu
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Yunxin Xie
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Junsong Yuan
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Yuan Zheng
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Yanyan Hu
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China
| | - Minglei Shi
- Bioinformatics Division, National Research Center for Information Science and Technology, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Kaiqiang You
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Tingting Li
- Department of Biomedical Informatics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Tianhua Ma
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China
| | - Michael Q Zhang
- Bioinformatics Division, National Research Center for Information Science and Technology, School of Medicine, Tsinghua University, Beijing 100084, China; Department of Biological Sciences, Center for Systems Biology, The University of Texas, Dallas, TX 75080-3021, USA
| | - Sheng Ding
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China
| | - Pilong Li
- State Key Laboratory of Membrane Biology, Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua University-Peking University Joint Center for Life Sciences, Beijing 100084, China.
| | - Yinqing Li
- The IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Bioinformatics, State Key Lab of Molecular Oncology, Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China.
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11
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Giudice J, Jiang H. Splicing regulation through biomolecular condensates and membraneless organelles. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00739-7. [PMID: 38773325 DOI: 10.1038/s41580-024-00739-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2024] [Indexed: 05/23/2024]
Abstract
Biomolecular condensates, sometimes also known as membraneless organelles (MLOs), can form through weak multivalent intermolecular interactions of proteins and nucleic acids, a process often associated with liquid-liquid phase separation. Biomolecular condensates are emerging as sites and regulatory platforms of vital cellular functions, including transcription and RNA processing. In the first part of this Review, we comprehensively discuss how alternative splicing regulates the formation and properties of condensates, and conversely the roles of biomolecular condensates in splicing regulation. In the second part, we focus on the spatial connection between splicing regulation and nuclear MLOs such as transcriptional condensates, splicing condensates and nuclear speckles. We then discuss key studies showing how splicing regulation through biomolecular condensates is implicated in human pathologies such as neurodegenerative diseases, different types of cancer, developmental disorders and cardiomyopathies, and conclude with a discussion of outstanding questions pertaining to the roles of condensates and MLOs in splicing regulation and how to experimentally study them.
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Affiliation(s)
- Jimena Giudice
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- McAllister Heart Institute, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Hao Jiang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA.
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12
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Shelkovnikova TA, Hautbergue GM. RNP granules in ALS and neurodegeneration: From multifunctional membraneless organelles to therapeutic opportunities. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 176:455-479. [PMID: 38802180 DOI: 10.1016/bs.irn.2024.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) and related neurodegenerative diseases are characterised by dysfunction of a host of RNA-binding proteins (RBPs) and a severely disrupted RNA metabolism. Recently, RBP-harbouring phase-separated complexes, ribonucleoprotein (RNP) granules, have come into the limelight as "crucibles" of neuronal pathology in ALS. RNP granules are indispensable for the multitude of regulatory processes underlying cellular RNA metabolism and serve as critical organisers of cellular biochemistry. Neurons, highly specialised cells, heavily rely on RNP granules for efficient trafficking, signalling and stress responses. Multiple RNP granule components, primarily RBPs such as TDP-43 and FUS, are affected by ALS mutations. However, even in the absence of mutations, RBP proteinopathies represent pathophysiological hallmarks of ALS. Given the high local concentrations of RBPs and RNAs, their weakened or enhanced interactions within RNP granules disrupt their homeostasis. Thus, the physiological process of phase separation and RNP granule formation, vital for maintaining the high-functioning state of neuronal cells, becomes their Achilles heel. Here, we will review the recent literature on the causes and consequences of abnormal RNP granule functioning in ALS and related disorders. In particular, we will summarise the evidence for the network-level dysfunction of RNP granules in these conditions and discuss considerations for therapeutic interventions to target RBPs, RNP granules and their network as a whole.
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Affiliation(s)
- Tatyana A Shelkovnikova
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom; Neuroscience Institute, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom.
| | - Guillaume M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom; Neuroscience Institute, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom; Healthy Lifespan Institute (HELSI), University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom.
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13
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Pantier R, Brown M, Han S, Paton K, Meek S, Montavon T, Shukeir N, McHugh T, Kelly DA, Hochepied T, Libert C, Jenuwein T, Burdon T, Bird A. MeCP2 binds to methylated DNA independently of phase separation and heterochromatin organisation. Nat Commun 2024; 15:3880. [PMID: 38719804 PMCID: PMC11079052 DOI: 10.1038/s41467-024-47395-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 03/29/2024] [Indexed: 05/12/2024] Open
Abstract
Correlative evidence has suggested that the methyl-CpG-binding protein MeCP2 contributes to the formation of heterochromatin condensates via liquid-liquid phase separation. This interpretation has been reinforced by the observation that heterochromatin, DNA methylation and MeCP2 co-localise within prominent foci in mouse cells. The findings presented here revise this view. MeCP2 localisation is independent of heterochromatin as MeCP2 foci persist even when heterochromatin organisation is disrupted. Additionally, MeCP2 foci fail to show hallmarks of phase separation in live cells. Importantly, we find that mouse cellular models are highly atypical as MeCP2 distribution is diffuse in most mammalian species, including humans. Notably, MeCP2 foci are absent in Mus spretus which is a mouse subspecies lacking methylated satellite DNA repeats. We conclude that MeCP2 has no intrinsic tendency to form condensates and its localisation is independent of heterochromatin. Instead, the distribution of MeCP2 in the nucleus is primarily determined by global DNA methylation patterns.
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Affiliation(s)
- Raphaël Pantier
- The Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, The King's Buildings, Edinburgh, EH9 3BF, UK
| | - Megan Brown
- The Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, The King's Buildings, Edinburgh, EH9 3BF, UK
| | - Sicheng Han
- The Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, The King's Buildings, Edinburgh, EH9 3BF, UK
| | - Katie Paton
- The Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, The King's Buildings, Edinburgh, EH9 3BF, UK
| | - Stephen Meek
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Thomas Montavon
- Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108, Freiburg, Germany
| | - Nicholas Shukeir
- Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108, Freiburg, Germany
| | - Toni McHugh
- The Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, The King's Buildings, Edinburgh, EH9 3BF, UK
| | - David A Kelly
- The Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, The King's Buildings, Edinburgh, EH9 3BF, UK
| | - Tino Hochepied
- Center for Inflammation Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Claude Libert
- Center for Inflammation Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Thomas Jenuwein
- Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108, Freiburg, Germany
| | - Tom Burdon
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Adrian Bird
- The Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Max Born Crescent, The King's Buildings, Edinburgh, EH9 3BF, UK.
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14
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Hedtfeld M, Dammers A, Koerner C, Musacchio A. A validation strategy to assess the role of phase separation as a determinant of macromolecular localization. Mol Cell 2024; 84:1783-1801.e7. [PMID: 38614097 DOI: 10.1016/j.molcel.2024.03.022] [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: 06/04/2023] [Revised: 12/11/2023] [Accepted: 03/22/2024] [Indexed: 04/15/2024]
Abstract
Liquid-liquid phase separation (LLPS) of putative assembly scaffolds has been proposed to drive the biogenesis of membraneless compartments. LLPS scaffolds are usually identified through in vitro LLPS assays with single macromolecules (homotypic), but the predictive value of these assays remains poorly characterized. Here, we apply a strategy to evaluate the robustness of homotypic LLPS assays. When applied to the chromosomal passenger complex (CPC), which undergoes LLPS in vitro and localizes to centromeres to promote chromosome biorientation, LLPS propensity in vitro emerged as an unreliable predictor of subcellular localization. In vitro CPC LLPS in aqueous buffers was enhanced by commonly used crowding agents. Conversely, diluted cytomimetic media dissolved condensates of the CPC and of several other proteins. We also show that centromeres do not seem to nucleate LLPS, nor do they promote local, spatially restrained LLPS of the CPC. Our strategy can be adapted to purported LLPS scaffolds of other membraneless compartments.
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Affiliation(s)
- Marius Hedtfeld
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany; Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
| | - Alicia Dammers
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Carolin Koerner
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Andrea Musacchio
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany; Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Essen, Germany.
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15
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Zheng H, Sun H, Cai Q, Tai HC. The Enigma of Tau Protein Aggregation: Mechanistic Insights and Future Challenges. Int J Mol Sci 2024; 25:4969. [PMID: 38732197 PMCID: PMC11084794 DOI: 10.3390/ijms25094969] [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: 03/30/2024] [Revised: 04/20/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024] Open
Abstract
Tau protein misfolding and aggregation are pathological hallmarks of Alzheimer's disease and over twenty neurodegenerative disorders. However, the molecular mechanisms of tau aggregation in vivo remain incompletely understood. There are two types of tau aggregates in the brain: soluble aggregates (oligomers and protofibrils) and insoluble filaments (fibrils). Compared to filamentous aggregates, soluble aggregates are more toxic and exhibit prion-like transmission, providing seeds for templated misfolding. Curiously, in its native state, tau is a highly soluble, heat-stable protein that does not form fibrils by itself, not even when hyperphosphorylated. In vitro studies have found that negatively charged molecules such as heparin, RNA, or arachidonic acid are generally required to induce tau aggregation. Two recent breakthroughs have provided new insights into tau aggregation mechanisms. First, as an intrinsically disordered protein, tau is found to undergo liquid-liquid phase separation (LLPS) both in vitro and inside cells. Second, cryo-electron microscopy has revealed diverse fibrillar tau conformations associated with different neurodegenerative disorders. Nonetheless, only the fibrillar core is structurally resolved, and the remainder of the protein appears as a "fuzzy coat". From this review, it appears that further studies are required (1) to clarify the role of LLPS in tau aggregation; (2) to unveil the structural features of soluble tau aggregates; (3) to understand the involvement of fuzzy coat regions in oligomer and fibril formation.
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Affiliation(s)
| | | | | | - Hwan-Ching Tai
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen 361102, China
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16
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Clarisse D, Van Moortel L, Van Leene C, Gevaert K, De Bosscher K. Glucocorticoid receptor signaling: intricacies and therapeutic opportunities. Trends Biochem Sci 2024; 49:431-444. [PMID: 38429217 DOI: 10.1016/j.tibs.2024.01.012] [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: 10/06/2023] [Revised: 01/10/2024] [Accepted: 01/31/2024] [Indexed: 03/03/2024]
Abstract
The glucocorticoid receptor (GR) is a major nuclear receptor (NR) drug target for the treatment of inflammatory disorders and several cancers. Despite the effectiveness of GR ligands, their systemic action triggers a plethora of side effects, limiting long-term use. Here, we discuss new concepts of and insights into GR mechanisms of action to assist in the identification of routes toward enhanced therapeutic benefits. We zoom in on the communication between different GR domains and how this is influenced by different ligands. We detail findings on the interaction between GR and chromatin, and highlight how condensate formation and coregulator confinement can perturb GR transcriptional responses. Last, we discuss the potential of novel ligands and the therapeutic exploitation of crosstalk with other NRs.
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Affiliation(s)
- Dorien Clarisse
- VIB Center for Medical Biotechnology, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Ghent, Belgium; Cancer Research Institute Ghent, Ghent, Belgium
| | - Laura Van Moortel
- VIB Center for Medical Biotechnology, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Ghent, Belgium; Cancer Research Institute Ghent, Ghent, Belgium
| | - Chloé Van Leene
- VIB Center for Medical Biotechnology, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Ghent, Belgium; Cancer Research Institute Ghent, Ghent, Belgium
| | - Kris Gevaert
- VIB Center for Medical Biotechnology, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Ghent, Belgium; Cancer Research Institute Ghent, Ghent, Belgium
| | - Karolien De Bosscher
- VIB Center for Medical Biotechnology, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Ghent, Belgium; Cancer Research Institute Ghent, Ghent, Belgium.
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17
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Egger T, Morano L, Blanchard MP, Basbous J, Constantinou A. Spatial organization and functions of Chk1 activation by TopBP1 biomolecular condensates. Cell Rep 2024; 43:114064. [PMID: 38578830 DOI: 10.1016/j.celrep.2024.114064] [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: 10/03/2023] [Revised: 02/14/2024] [Accepted: 03/21/2024] [Indexed: 04/07/2024] Open
Abstract
Assembly of TopBP1 biomolecular condensates triggers activation of the ataxia telangiectasia-mutated and Rad3-related (ATR)/Chk1 signaling pathway, which coordinates cell responses to impaired DNA replication. Here, we used optogenetics and reverse genetics to investigate the role of sequence-specific motifs in the formation and functions of TopBP1 condensates. We propose that BACH1/FANCJ is involved in the partitioning of BRCA1 within TopBP1 compartments. We show that Chk1 is activated at the interface of TopBP1 condensates and provide evidence that these structures arise at sites of DNA damage and in primary human fibroblasts. Chk1 phosphorylation depends on the integrity of a conserved arginine motif within TopBP1's ATR activation domain (AAD). Its mutation uncouples Chk1 activation from TopBP1 condensation, revealing that optogenetically induced Chk1 phosphorylation triggers cell cycle checkpoints and slows down replication forks in the absence of DNA damage. Together with previous work, these data suggest that the intrinsically disordered AAD encodes distinct molecular steps in the ATR/Chk1 pathway.
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Affiliation(s)
- Tom Egger
- Institut de Génétique Humaine, Université de Montpellier, CNRS, Montpellier, France
| | - Laura Morano
- Institut de Génétique Humaine, Université de Montpellier, CNRS, Montpellier, France
| | - Marie-Pierre Blanchard
- Montpellier Ressources Imageries, BioCampus, Université de Montpellier, CNRS, Montpellier, France
| | - Jihane Basbous
- Institut de Génétique Humaine, Université de Montpellier, CNRS, Montpellier, France.
| | - Angelos Constantinou
- Institut de Génétique Humaine, Université de Montpellier, CNRS, Montpellier, France
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18
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Hoang Y, Azaldegui CA, Dow RE, Ghalmi M, Biteen JS, Vecchiarelli AG. An experimental framework to assess biomolecular condensates in bacteria. Nat Commun 2024; 15:3222. [PMID: 38622124 PMCID: PMC11018776 DOI: 10.1038/s41467-024-47330-4] [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: 04/04/2023] [Accepted: 03/28/2024] [Indexed: 04/17/2024] Open
Abstract
High-resolution imaging of biomolecular condensates in living cells is essential for correlating their properties to those observed through in vitro assays. However, such experiments are limited in bacteria due to resolution limitations. Here we present an experimental framework that probes the formation, reversibility, and dynamics of condensate-forming proteins in Escherichia coli as a means to determine the nature of biomolecular condensates in bacteria. We demonstrate that condensates form after passing a threshold concentration, maintain a soluble fraction, dissolve upon shifts in temperature and concentration, and exhibit dynamics consistent with internal rearrangement and exchange between condensed and soluble fractions. We also discover that an established marker for insoluble protein aggregates, IbpA, has different colocalization patterns with bacterial condensates and aggregates, demonstrating its potential applicability as a reporter to differentiate the two in vivo. Overall, this framework provides a generalizable, accessible, and rigorous set of experiments to probe the nature of biomolecular condensates on the sub-micron scale in bacterial cells.
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Affiliation(s)
- Y Hoang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | | | - Rachel E Dow
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Maria Ghalmi
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Julie S Biteen
- Doctoral Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Anthony G Vecchiarelli
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
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19
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Lizana L, Schwartz YB. The scales, mechanisms, and dynamics of the genome architecture. SCIENCE ADVANCES 2024; 10:eadm8167. [PMID: 38598632 PMCID: PMC11006219 DOI: 10.1126/sciadv.adm8167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/06/2024] [Indexed: 04/12/2024]
Abstract
Even when split into several chromosomes, DNA molecules that make up our genome are too long to fit into the cell nuclei unless massively folded. Such folding must accommodate the need for timely access to selected parts of the genome by transcription factors, RNA polymerases, and DNA replication machinery. Here, we review our current understanding of the genome folding inside the interphase nuclei. We consider the resulting genome architecture at three scales with a particular focus on the intermediate (meso) scale and summarize the insights gained from recent experimental observations and diverse computational models.
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Affiliation(s)
- Ludvig Lizana
- Integrated Science Lab, Department of Physics, Umeå University, Umeå, Sweden
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20
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Ling YH, Ye Z, Liang C, Yu C, Park G, Corden JL, Wu C. Disordered C-terminal domain drives spatiotemporal confinement of RNAPII to enhance search for chromatin targets. Nat Cell Biol 2024; 26:581-592. [PMID: 38548891 PMCID: PMC11210292 DOI: 10.1038/s41556-024-01382-2] [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: 08/01/2023] [Accepted: 02/21/2024] [Indexed: 04/09/2024]
Abstract
Efficient gene expression requires RNA polymerase II (RNAPII) to find chromatin targets precisely in space and time. How RNAPII manages this complex diffusive search in three-dimensional nuclear space remains largely unknown. The disordered carboxy-terminal domain (CTD) of RNAPII, which is essential for recruiting transcription-associated proteins, forms phase-separated droplets in vitro, hinting at a potential role in modulating RNAPII dynamics. In the present study, we use single-molecule tracking and spatiotemporal mapping in living yeast to show that the CTD is required for confining RNAPII diffusion within a subnuclear region enriched for active genes, but without apparent phase separation into condensates. Both Mediator and global chromatin organization are required for sustaining RNAPII confinement. Remarkably, truncating the CTD disrupts RNAPII spatial confinement, prolongs target search, diminishes chromatin binding, impairs pre-initiation complex formation and reduces transcription bursting. The present study illuminates the pivotal role of the CTD in driving spatiotemporal confinement of RNAPII for efficient gene expression.
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Affiliation(s)
- Yick Hin Ling
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Ziyang Ye
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Chloe Liang
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Chuofan Yu
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Giho Park
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Jeffry L Corden
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carl Wu
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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21
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Lin W, Nagy PD. Co-opted cytosolic proteins form condensate substructures within membranous replication organelles of a positive-strand RNA virus. THE NEW PHYTOLOGIST 2024. [PMID: 38515267 DOI: 10.1111/nph.19691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/22/2024] [Indexed: 03/23/2024]
Abstract
Positive-strand RNA viruses co-opt organellar membranes for biogenesis of viral replication organelles (VROs). Tombusviruses also co-opt pro-viral cytosolic proteins to VROs. It is currently not known what type of molecular organization keeps co-opted proteins sequestered within membranous VROs. In this study, we employed tomato bushy stunt virus (TBSV) and carnation Italian ringspot virus (CIRV) - Nicotiana benthamiana pathosystems to identify biomolecular condensate formation in VROs. We show that TBSV p33 and the CIRV p36 replication proteins sequester glycolytic and fermentation enzymes in unique condensate substructures associated with membranous VROs. We find that p33 and p36 form droplets in vitro driven by intrinsically disordered region. The replication protein organizes partitioning of co-opted host proteins into droplets. VRO-associated condensates are critical for local adenosine triphosphate production to support energy for virus replication. We find that co-opted endoplasmic reticulum membranes and actin filaments form meshworks within and around VRO condensates, contributing to unique composition and structure. We propose that p33/p36 organize liquid-liquid phase separation of co-opted concentrated host proteins in condensate substructures within membranous VROs. Overall, we demonstrate that subverted membranes and condensate substructures co-exist and are critical for VRO functions. The replication proteins induce and connect the two substructures within VROs.
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Affiliation(s)
- Wenwu Lin
- Department of Plant Pathology, University of Kentucky, Lexington, KY, 40543, USA
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, KY, 40543, USA
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22
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Sundara Rajan S, Ebegboni VJ, Pichling P, Ludwig KR, Jones TL, Chari R, Tran A, Kruhlak MJ, Loncarek J, Caplen NJ. Endogenous EWSR1 Exists in Two Visual Modalities That Reflect Its Associations with Nucleic Acids and Concentration at Sites of Active Transcription. Mol Cell Biol 2024; 44:103-122. [PMID: 38506112 PMCID: PMC10986767 DOI: 10.1080/10985549.2024.2315425] [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: 01/10/2024] [Accepted: 02/02/2024] [Indexed: 03/21/2024] Open
Abstract
EWSR1 is a member of the FET family of nucleic acid binding proteins that includes FUS and TAF15. Here, we report the systematic analysis of endogenous EWSR1's cellular organization in human cells. We demonstrate that EWSR1, which contains low complexity and nucleic acid binding domains, is present in cells in faster and slower-recovering fractions, indicative of a protein undergoing both rapid exchange and longer-term interactions. The employment of complementary high-resolution imaging approaches shows EWSR1 exists in two visual modalities, a distributed state which is present throughout the nucleoplasm, and a concentrated state consistent with the formation of foci. Both EWSR1 visual modalities localize with nascent RNA. EWSR1 foci concentrate in regions of euchromatin, adjacent to protein markers of transcriptional activation, and significantly colocalize with phosphorylated RNA polymerase II. Our results contribute to bridging the gap between our understanding of the biophysical and biochemical properties of FET proteins, including EWSR1, their functions as transcriptional regulators, and the participation of these proteins in tumorigenesis and neurodegenerative disease.
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Affiliation(s)
- Soumya Sundara Rajan
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Vernon J. Ebegboni
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Patricio Pichling
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Katelyn R. Ludwig
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Tamara L. Jones
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Raj Chari
- Genome Modification Core, Laboratory Animal Sciences Program, Frederick National Lab for Cancer Research, Frederick, Maryland, USA
| | - Andy Tran
- CCR Confocal Microscopy Core Facility, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Michael J. Kruhlak
- CCR Confocal Microscopy Core Facility, Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jadranka Loncarek
- Centrosome Biology Section, Cancer Innovation Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Natasha J. Caplen
- Functional Genetics Section, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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23
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Unarta IC, Cao S, Goonetilleke EC, Niu J, Gellman SH, Huang X. Submillisecond Atomistic Molecular Dynamics Simulations Reveal Hydrogen Bond-Driven Diffusion of a Guest Peptide in Protein-RNA Condensate. J Phys Chem B 2024; 128:2347-2359. [PMID: 38416758 PMCID: PMC11057999 DOI: 10.1021/acs.jpcb.3c08126] [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] [Indexed: 03/01/2024]
Abstract
Liquid-liquid phase separation mediated by proteins and/or nucleic acids is believed to underlie the formation of many distinct condensed phases, or membraneless organelles, within living cells. These condensates have been proposed to orchestrate a variety of important processes. Despite recent advances, the interactions that regulate the dynamics of molecules within a condensate remain poorly understood. We performed accumulated 564.7 μs all-atom molecular dynamics (MD) simulations (system size ∼200k atoms) of model condensates formed by a scaffold RNA oligomer and a scaffold peptide rich in arginine (Arg). These model condensates contained one of three possible guest peptides: the scaffold peptide itself or a variant in which six Arg residues were replaced by lysine (Lys) or asymmetric dimethyl arginine (ADMA). We found that the Arg-rich peptide can form the largest number of hydrogen bonds and bind the strongest to the scaffold RNA in the condensate, relative to the Lys- and ADMA-rich peptides. Our MD simulations also showed that the Arg-rich peptide diffused more slowly in the condensate relative to the other two guest peptides, which is consistent with a recent fluorescence microscopy study. There was no significant increase in the number of cation-π interactions between the Arg-rich peptide and the scaffold RNA compared to the Lys-rich and ADMA-rich peptides. Our results indicate that hydrogen bonds between the peptides and the RNA backbone, rather than cation-π interactions, play a major role in regulating peptide diffusion in the condensate.
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Affiliation(s)
- Ilona C. Unarta
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Siqin Cao
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Eshani C. Goonetilleke
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Jiani Niu
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Samuel H. Gellman
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Xuhui Huang
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, WI, 53706, USA
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24
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Huo M, Rai SK, Nakatsu K, Deng Y, Jijiwa M. Subverting the Canon: Novel Cancer-Promoting Functions and Mechanisms for snoRNAs. Int J Mol Sci 2024; 25:2923. [PMID: 38474168 PMCID: PMC10932220 DOI: 10.3390/ijms25052923] [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: 01/18/2024] [Revised: 02/27/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
Small nucleolar RNAs (snoRNAs) constitute a class of intron-derived non-coding RNAs ranging from 60 to 300 nucleotides. Canonically localized in the nucleolus, snoRNAs play a pivotal role in RNA modifications and pre-ribosomal RNA processing. Based on the types of modifications they involve, such as methylation and pseudouridylation, they are classified into two main families-box C/D and H/ACA snoRNAs. Recent investigations have revealed the unconventional synthesis and biogenesis strategies of snoRNAs, indicating their more profound roles in pathogenesis than previously envisioned. This review consolidates recent discoveries surrounding snoRNAs and provides insights into their mechanistic roles in cancer. It explores the intricate interactions of snoRNAs within signaling pathways and speculates on potential therapeutic solutions emerging from snoRNA research. In addition, it presents recent findings on the long non-coding small nucleolar RNA host gene (lncSNHG), a subset of long non-coding RNAs (lncRNAs), which are the transcripts of parental SNHGs that generate snoRNA. The nucleolus, the functional epicenter of snoRNAs, is also discussed. Through a deconstruction of the pathways driving snoRNA-induced oncogenesis, this review aims to serve as a roadmap to guide future research in the nuanced field of snoRNA-cancer interactions and inspire potential snoRNA-related cancer therapies.
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Affiliation(s)
- Matthew Huo
- Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD 21218, USA;
- Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA; (S.K.R.); (K.N.)
| | - Sudhir Kumar Rai
- Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA; (S.K.R.); (K.N.)
| | - Ken Nakatsu
- Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA; (S.K.R.); (K.N.)
- Emory College of Arts and Sciences, Emory University, Atlanta, GA 30322, USA
| | - Youping Deng
- Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA; (S.K.R.); (K.N.)
| | - Mayumi Jijiwa
- Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA; (S.K.R.); (K.N.)
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25
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Ahangama Liyanage L, Ditlev JA. Mesoscale condensates organize the cytoplasm. Nat Cell Biol 2024; 26:310-312. [PMID: 38424272 DOI: 10.1038/s41556-023-01331-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Affiliation(s)
- Leshani Ahangama Liyanage
- Programs in Molecular Medicine and Cell Biology, Hospital for Sick Children and Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jonathon A Ditlev
- Programs in Molecular Medicine and Cell Biology, Hospital for Sick Children and Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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26
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Stortz M, Presman DM, Levi V. Transcriptional condensates: a blessing or a curse for gene regulation? Commun Biol 2024; 7:187. [PMID: 38365945 PMCID: PMC10873363 DOI: 10.1038/s42003-024-05892-5] [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: 10/26/2023] [Accepted: 02/06/2024] [Indexed: 02/18/2024] Open
Abstract
Whether phase-separation is involved in the organization of the transcriptional machinery and if it aids or inhibits the transcriptional process is a matter of intense debate. In this Mini Review, we will cover the current knowledge regarding the role of transcriptional condensates on gene expression regulation. We will summarize the latest discoveries on the relationship between condensate formation, genome organization, and transcriptional activity, focusing on the strengths and weaknesses of the experimental approaches used to interrogate these aspects of transcription in living cells. Finally, we will discuss the challenges for future research.
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Grants
- PICT 2020-00818 Ministry of Science, Technology and Productive Innovation, Argentina | Agencia Nacional de Promoción Científica y Tecnológica (National Agency for Science and Technology, Argentina)
- PICT-2018-1921 Ministry of Science, Technology and Productive Innovation, Argentina | Agencia Nacional de Promoción Científica y Tecnológica (National Agency for Science and Technology, Argentina)
- PICT 2019-0397 Ministry of Science, Technology and Productive Innovation, Argentina | Agencia Nacional de Promoción Científica y Tecnológica (National Agency for Science and Technology, Argentina)
- 20020190100101BA University of Buenos Aires | Secretaría de Ciencia y Técnica, Universidad de Buenos Aires (Secretaría de Ciencia y Técnica de la Universidad de Buenos Aires)
- 2022-11220210100212CO Consejo Nacional de Investigaciones Científicas y Técnicas (National Scientific and Technical Research Council)
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Affiliation(s)
- Martin Stortz
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Diego M Presman
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), CONICET-Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Buenos Aires, C1428EGA, Argentina.
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina.
| | - Valeria Levi
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina.
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina.
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27
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Subramanya AR, Boyd-Shiwarski CR. Molecular Crowding: Physiologic Sensing and Control. Annu Rev Physiol 2024; 86:429-452. [PMID: 37931170 DOI: 10.1146/annurev-physiol-042222-025920] [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] [Indexed: 11/08/2023]
Abstract
The cytoplasm is densely packed with molecules that contribute to its nonideal behavior. Cytosolic crowding influences chemical reaction rates, intracellular water mobility, and macromolecular complex formation. Overcrowding is potentially catastrophic; to counteract this problem, cells have evolved acute and chronic homeostatic mechanisms that optimize cellular crowdedness. Here, we provide a physiology-focused overview of molecular crowding, highlighting contemporary advances in our understanding of its sensing and control. Long hypothesized as a form of crowding-induced microcompartmentation, phase separation allows cells to detect and respond to intracellular crowding through the action of biomolecular condensates, as indicated by recent studies. Growing evidence indicates that crowding is closely tied to cell size and fluid volume, homeostatic responses to physical compression and desiccation, tissue architecture, circadian rhythm, aging, transepithelial transport, and total body electrolyte and water balance. Thus, molecular crowding is a fundamental physiologic parameter that impacts diverse functions extending from molecule to organism.
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Affiliation(s)
- Arohan R Subramanya
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA; ,
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh Center for Kidney Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, USA
| | - Cary R Boyd-Shiwarski
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA; ,
- Pittsburgh Center for Kidney Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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28
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Lee J, Simpson L, Li Y, Becker S, Zou F, Zhang X, Bai L. Transcription Factor Condensates Mediate Clustering of MET Regulon and Enhancement in Gene Expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.06.579062. [PMID: 38370634 PMCID: PMC10871269 DOI: 10.1101/2024.02.06.579062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Some transcription factors (TFs) can form liquid-liquid phase separated (LLPS) condensates. However, the functions of these TF condensates in 3D genome organization and gene regulation remain elusive. In response to methionine (met) starvation, budding yeast TF Met4 and a few co-activators, including Met32, induce a set of genes involved in met biosynthesis. Here, we show that the endogenous Met4 and Met32 form co-localized puncta-like structures in yeast nuclei upon met depletion. Recombinant Met4 and Met32 form mixed droplets with LLPS properties in vitro. In relation to chromatin, Met4 puncta co-localize with target genes, and at least a subset of these target genes are clustered in 3D in a Met4-dependent manner. A MET3pr-GFP reporter inserted near several native Met4 binding sites becomes co-localized with Met4 puncta and displays enhanced transcriptional activity. A Met4 variant with a partial truncation of an intrinsically disordered region (IDR) shows less puncta formation, and this mutant selectively reduces the reporter activity near Met4 binding sites to the basal level. Overall, these results support a model where Met4 and co-activators form condensates to bring multiple target genes into a vicinity with higher local TF concentrations, which facilitates a strong response to methionine depletion.
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Affiliation(s)
- James Lee
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Leman Simpson
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Yi Li
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Samuel Becker
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Fan Zou
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Xin Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Lu Bai
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
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29
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Hannon CE, Eisen MB. Intrinsic protein disorder is insufficient to drive subnuclear clustering in embryonic transcription factors. eLife 2024; 12:RP88221. [PMID: 38275292 PMCID: PMC10945700 DOI: 10.7554/elife.88221] [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] [Indexed: 01/27/2024] Open
Abstract
Modern microscopy has revealed that core nuclear functions, including transcription, replication, and heterochromatin formation, occur in spatially restricted clusters. Previous work from our lab has shown that subnuclear high-concentration clusters of transcription factors may play a role in regulating RNA synthesis in the early Drosophila embryo. A nearly ubiquitous feature of eukaryotic transcription factors is that they contain intrinsically disordered regions (IDRs) that often arise from low complexity amino acid sequences within the protein. It has been proposed that IDRs within transcription factors drive co-localization of transcriptional machinery and target genes into high-concentration clusters within nuclei. Here, we test that hypothesis directly, by conducting a broad survey of the subnuclear localization of IDRs derived from transcription factors. Using a novel algorithm to identify IDRs in the Drosophila proteome, we generated a library of IDRs from transcription factors expressed in the early Drosophila embryo. We used this library to perform a high-throughput imaging screen in Drosophila Schneider-2 (S2) cells. We found that while subnuclear clustering does not occur when the majority of IDRs are expressed alone, it is frequently seen in full-length transcription factors. These results are consistent in live Drosophila embryos, suggesting that IDRs are insufficient to drive the subnuclear clustering behavior of transcription factors. Furthermore, the clustering of transcription factors in living embryos was unaffected by the deletion of IDR sequences. Our results demonstrate that IDRs are unlikely to be the primary molecular drivers of the clustering observed during transcription, suggesting a more complex and nuanced role for these disordered protein sequences.
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Affiliation(s)
- Colleen E Hannon
- Howard Hughes Medical Institute, University of CaliforniaBerkeleyUnited States
| | - Michael B Eisen
- Howard Hughes Medical Institute, University of CaliforniaBerkeleyUnited States
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30
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Chattaraj A, Baltaci Z, Mayer BJ, Loew LM, Ditlev JA. Measurement of solubility product in a model condensate reveals the interplay of small oligomerization and self-association. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.23.576869. [PMID: 38328089 PMCID: PMC10849621 DOI: 10.1101/2024.01.23.576869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Cellular condensates often consist of 10s to 100s of distinct interacting molecular species. Because of the complexity of these interactions, predicting the point at which they will undergo phase separation into discrete compartments is daunting. Using experiments and computation, we therefore studied a simple model system consisting of 2 proteins, polySH3 and polyPRM, designed for pentavalent heterotypic binding. We tested whether the peak solubility product, the product of dilute phase monomer concentrations, is a predictive parameter for the onset of phase separation. Titrating up equal total concentrations of each component showed that the maximum solubility product does approximately coincide with the threshold for phase separation in both the experiments and models. However, we found that measurements of dilute phase concentration include contributions from small oligomers, not just monomers; therefore, a quantitative comparison of the experiments and models required inclusion of small oligomers in the model analysis. We also examined full phase diagrams where the model results were almost symmetric along the diagonal, but the experimental results were highly asymmetric. This led us to perform dynamic light scattering experiments, where we discovered a weak homotypic interaction for polyPRM; when this was added to the computational model, it was able to recapitulate the experimentally observed asymmetry. Thus, comparing experiments to simulation reveals that the solubility product can be predictive of phase separation, even if small oligomers and low affinity homotypic interactions preclude experimental measurement of monomer concentration.
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Affiliation(s)
- Aniruddha Chattaraj
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, Connecticut, United States of America
| | - Zeynep Baltaci
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Bruce J. Mayer
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, Connecticut, United States of America
- Genetics and Genome Sciences, University of Connecticut School of Medicine, Farmington, Connecticut, United States of America
| | - Leslie M. Loew
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, Connecticut, United States of America
| | - Jonathon A. Ditlev
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
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31
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Heinrich S, Hondele M, Marchand D, Derrer CP, Zedan M, Oswald A, Malinovska L, Uliana F, Khawaja S, Mancini R, Grunwald D, Weis K. Glucose stress causes mRNA retention in nuclear Nab2 condensates. Cell Rep 2024; 43:113593. [PMID: 38113140 DOI: 10.1016/j.celrep.2023.113593] [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: 03/10/2022] [Revised: 10/12/2023] [Accepted: 11/30/2023] [Indexed: 12/21/2023] Open
Abstract
Nuclear mRNA export via nuclear pore complexes is an essential step in eukaryotic gene expression. Although factors involved in mRNA transport have been characterized, a comprehensive mechanistic understanding of this process and its regulation is lacking. Here, we use single-RNA imaging in yeast to show that cells use mRNA retention to control mRNA export during stress. We demonstrate that, upon glucose withdrawal, the essential RNA-binding factor Nab2 forms RNA-dependent condensate-like structures in the nucleus. This coincides with a reduced abundance of the DEAD-box ATPase Dbp5 at the nuclear pore. Depleting Dbp5, and consequently blocking mRNA export, is necessary and sufficient to trigger Nab2 condensation. The state of Nab2 condensation influences the extent of nuclear mRNA accumulation and can be recapitulated in vitro, where Nab2 forms RNA-dependent liquid droplets. We hypothesize that cells use condensation to regulate mRNA export and control gene expression during stress.
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Affiliation(s)
- Stephanie Heinrich
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland.
| | - Maria Hondele
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland; Biozentrum, Center for Molecular Life Sciences, University of Basel, 4056 Basel, Switzerland
| | - Désirée Marchand
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland
| | - Carina Patrizia Derrer
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland
| | - Mostafa Zedan
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland
| | - Alexandra Oswald
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland
| | - Liliana Malinovska
- Department of Biology, Institute of Molecular Systems Biology, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland
| | - Federico Uliana
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland
| | - Sarah Khawaja
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland
| | - Roberta Mancini
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland
| | - David Grunwald
- University of Massachusetts Chan Medical School, RNA Therapeutics Institute, Worcester, MA 01605, USA
| | - Karsten Weis
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology (ETH), 8093 Zurich, Switzerland.
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32
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Mehta N, Mondal S, Watson ET, Cui Q, Chapman ER. The juxtamembrane linker of synaptotagmin 1 regulates Ca 2+ binding via liquid-liquid phase separation. Nat Commun 2024; 15:262. [PMID: 38177243 PMCID: PMC10766989 DOI: 10.1038/s41467-023-44414-5] [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: 08/11/2023] [Accepted: 12/12/2023] [Indexed: 01/06/2024] Open
Abstract
Synaptotagmin (syt) 1, a Ca2+ sensor for synaptic vesicle exocytosis, functions in vivo as a multimer. Syt1 senses Ca2+ via tandem C2-domains that are connected to a single transmembrane domain via a juxtamembrane linker. Here, we show that this linker segment harbors a lysine-rich, intrinsically disordered region that is necessary and sufficient to mediate liquid-liquid phase separation (LLPS). Interestingly, condensate formation negatively regulates the Ca2+-sensitivity of syt1. Moreover, Ca2+ and anionic phospholipids facilitate the observed phase separation, and increases in [Ca2+]i promote the fusion of syt1 droplets in living cells. Together, these observations suggest a condensate-mediated feedback loop that serves to fine-tune the ability of syt1 to trigger release, via alterations in Ca2+ binding activity and potentially through the impact of LLPS on membrane curvature during fusion reactions. In summary, the juxtamembrane linker of syt1 emerges as a regulator of syt1 function by driving self-association via LLPS.
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Affiliation(s)
- Nikunj Mehta
- Howard Hughes Medical Institute, Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Sayantan Mondal
- Department of Chemistry, Boston University, Boston, MA, 02215, USA
| | - Emma T Watson
- Howard Hughes Medical Institute, Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Qiang Cui
- Department of Chemistry, Boston University, Boston, MA, 02215, USA
| | - Edwin R Chapman
- Howard Hughes Medical Institute, Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, 53705, USA.
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33
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Asuelime-Smith MBT, Ma DZ. Investigating Liquid-Liquid Phase Separation in Virus-Generated Inclusion Bodies Using Fluorescence Recovery After Photobleaching of Fluorescently Labeled Host Proteins. Methods Mol Biol 2024; 2808:129-140. [PMID: 38743367 DOI: 10.1007/978-1-0716-3870-5_10] [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] [Indexed: 05/16/2024]
Abstract
Many negative-sense single-stranded RNA viruses within the order Mononegavirales harm humans. A common feature shared among cells infected by these viruses is the formation of subcellular membraneless structures called biomolecular condensates, also known as inclusion bodies (IBs), that form through a process called liquid-liquid phase separation (LLPS). Like many other membraneless organelles, viral IBs enrich a specific subset of viral and host proteins involved in the formation of viral particles. Elucidation of the properties and regulation of these IBs as they mature throughout the viral replication process are important for our understanding of viral replication, which may also lead to the development of alternative antiviral treatments. The protocol outlined in this chapter aims to characterize the intrinsic properties of LLPS within the measles virus (MeV, a member of Mononegavirales) IBs by using an imaging approach that fluorescently tags an IB-associated host protein. This method uses common laboratory techniques and is generalizable to any host factors as well as other viral systems.
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Affiliation(s)
- Matthew B T Asuelime-Smith
- The Department of Molecular, Cell, and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Dzwokai Z Ma
- Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA, USA.
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34
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Gorsheneva NA, Sopova JV, Azarov VV, Grizel AV, Rubel AA. Biomolecular Condensates: Structure, Functions, Methods of Research. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:S205-S223. [PMID: 38621751 DOI: 10.1134/s0006297924140116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/12/2023] [Accepted: 10/16/2023] [Indexed: 04/17/2024]
Abstract
The term "biomolecular condensates" is used to describe membraneless compartments in eukaryotic cells, accumulating proteins and nucleic acids. Biomolecular condensates are formed as a result of liquid-liquid phase separation (LLPS). Often, they demonstrate properties of liquid-like droplets or gel-like aggregates; however, some of them may appear to have a more complex structure and high-order organization. Membraneless microcompartments are involved in diverse processes both in cytoplasm and in nucleus, among them ribosome biogenesis, regulation of gene expression, cell signaling, and stress response. Condensates properties and structure could be highly dynamic and are affected by various internal and external factors, e.g., concentration and interactions of components, solution temperature, pH, osmolarity, etc. In this review, we discuss variety of biomolecular condensates and their functions in live cells, describe their structure variants, highlight domain and primary sequence organization of the constituent proteins and nucleic acids. Finally, we describe current advances in methods that characterize structure, properties, morphology, and dynamics of biomolecular condensates in vitro and in vivo.
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Affiliation(s)
| | - Julia V Sopova
- St. Petersburg State University, St. Petersburg, 199034, Russia.
| | | | - Anastasia V Grizel
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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35
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Volkov VA, Akhmanova A. Phase separation on microtubules: from droplet formation to cellular function? Trends Cell Biol 2024; 34:18-30. [PMID: 37453878 DOI: 10.1016/j.tcb.2023.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/18/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
Microtubules are cytoskeletal polymers that play important roles in numerous cellular processes, ranging from the control of cell shape and polarity to cell division and intracellular transport. Many of these roles rely on proteins that bind to microtubule ends and shafts, carry intrinsically disordered regions, and form complex multivalent interaction networks. A flurry of recent studies demonstrated that these properties allow diverse microtubule-binding proteins to undergo liquid-liquid phase separation (LLPS) in vitro. It is proposed that LLPS could potentially affect multiple microtubule-related processes, such as microtubule nucleation, control of microtubule dynamics and organization, and microtubule-based transport. Here, we discuss the evidence in favor and against the occurrence of LLPS and its functional significance for microtubule-based processes in cells.
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Affiliation(s)
- Vladimir A Volkov
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, E1 4NS, UK.
| | - Anna Akhmanova
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands.
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36
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Liu J, Fan H, Liang X, Chen Y. Polycomb repressor complex: Its function in human cancer and therapeutic target strategy. Biomed Pharmacother 2023; 169:115897. [PMID: 37981459 DOI: 10.1016/j.biopha.2023.115897] [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: 09/13/2023] [Revised: 11/07/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023] Open
Abstract
The Polycomb Repressor Complex (PRC) plays a pivotal role in gene regulation during development and disease, with dysregulation contributing significantly to various human cancers. The intricate interplay between PRC and cellular signaling pathways sheds light on cancer complexity. PRC presents promising therapeutic opportunities, with inhibitors undergoing rigorous evaluation in preclinical and clinical studies. In this review, we emphasize the critical role of PRC complex in gene regulation, particularly PcG proteins mediated chromatin compaction through phase separation. We also highlight the pathological implications of PRC complex dysregulation in various tumors, elucidating underlying mechanisms driving cancer progression. The burgeoning field of therapeutic strategies targeting PRC complexes, notably EZH2 inhibitors, has advanced significantly. However, we explore the need for combination therapies to enhance PRC targeted treatments efficacy, providing a glimpse into the future of cancer therapeutics.
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Affiliation(s)
- Jingrong Liu
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China
| | - Hongjie Fan
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China
| | - Xinmiao Liang
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Yang Chen
- Ganjiang Chinese Medicine Innovation Center, Nanchang 330000, China; CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
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37
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Xie P, Xie X, Ye C, Dean KM, Laothamatas I, Taufique SKT, Takahashi J, Yamazaki S, Xu Y, Liu Y. Mammalian circadian clock proteins form dynamic interacting microbodies distinct from phase separation. Proc Natl Acad Sci U S A 2023; 120:e2318274120. [PMID: 38127982 PMCID: PMC10756265 DOI: 10.1073/pnas.2318274120] [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: 10/28/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Liquid-liquid phase separation (LLPS) underlies diverse biological processes. Because most LLPS studies were performed in vitro using recombinant proteins or in cells that overexpress protein, the physiological relevance of LLPS for endogenous protein is often unclear. PERIOD, the intrinsically disordered domain-rich proteins, are central mammalian circadian clock components and interact with other clock proteins in the core circadian negative feedback loop. Different core clock proteins were previously shown to form large complexes. Circadian clock studies often rely on experiments that overexpress clock proteins. Here, we show that when Per2 transgene was stably expressed in cells, PER2 protein formed nuclear phosphorylation-dependent slow-moving LLPS condensates that recruited other clock proteins. Super-resolution microscopy of endogenous PER2, however, revealed formation of circadian-controlled, rapidly diffusing nuclear microbodies that were resistant to protein concentration changes, hexanediol treatment, and loss of phosphorylation, indicating that they are distinct from the LLPS condensates caused by protein overexpression. Surprisingly, only a small fraction of endogenous PER2 microbodies transiently interact with endogenous BMAL1 and CRY1, a conclusion that was confirmed in cells and in mice tissues, suggesting an enzyme-like mechanism in the circadian negative feedback process. Together, these results demonstrate that the dynamic interactions of core clock proteins are a key feature of mammalian circadian clock mechanism and the importance of examining endogenous proteins in LLPS and circadian clock studies.
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Affiliation(s)
- Pancheng Xie
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX75390
- Cambridge-Su Genomic Resource Center, Soochow University, Suzhou, Jiangsu215123, China
| | - Xiaowen Xie
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Congrong Ye
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Kevin M. Dean
- Lyda Hill Department of Bioinformatics and Cecil H. and Ida Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX75390
| | - Isara Laothamatas
- HHMI, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
| | - S. K. Tahajjul Taufique
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
| | - Joseph Takahashi
- HHMI, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
| | - Shin Yamazaki
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
- Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX75390-9111
| | - Ying Xu
- Cambridge-Su Genomic Resource Center, Soochow University, Suzhou, Jiangsu215123, China
| | - Yi Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX75390
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38
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Silonov SA, Smirnov EY, Shmidt EA, Kuznetsova IM, Turoverov KK, Fonin AV. Insights into the Cellular Localization and Functional Properties of TSPYL5 Protein. Int J Mol Sci 2023; 25:39. [PMID: 38203210 PMCID: PMC10779080 DOI: 10.3390/ijms25010039] [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: 11/09/2023] [Revised: 12/11/2023] [Accepted: 12/16/2023] [Indexed: 01/12/2024] Open
Abstract
In recent years, the role of liquid-liquid phase separation (LLPS) and intrinsically disordered proteins (IDPs) in cellular molecular processes has received increasing attention from researchers. One such intrinsically disordered protein is TSPYL5, considered both as a marker and a potential therapeutic target for various oncological diseases. However, the role of TSPYL5 in intracellular processes remains unknown, and there is no clarity even in its intracellular localization. In this study, we characterized the intracellular localization and exchange dynamics with intracellular contents of TSPYL5 and its parts, utilizing TSPYL5 fusion proteins with EGFP. Our findings reveal that TSPYL5 can be localized in both the cytoplasm and nucleoplasm, including the nucleolus. The nuclear (nucleolar) localization of TSPYL5 is mediated by the nuclear/nucleolar localization sequences (NLS/NoLS) identified in the N-terminal intrinsically disordered region (4-27 aa), while its cytoplasmic localization is regulated by the ordered NAP-like domain (198-382 aa). Furthermore, our results underscore the significant role of the TSPYL5 N-terminal disordered region (1-198 aa) in the exchange dynamics with the nucleoplasm and its potential ability for phase separation. Bioinformatics analysis of the TSPYL5 interactome indicates its potential function as a histone and ribosomal protein chaperone. Taken together, these findings suggest a significant contribution of liquid-liquid phase separation to the processes involving TSPYL5, providing new insights into the role of this protein in the cell's molecular life.
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Affiliation(s)
- Sergey A. Silonov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Russian Academy of Sciences, St. Petersburg 194064, Russia; (E.Y.S.); (E.A.S.); (I.M.K.); (K.K.T.)
| | | | | | | | | | - Alexander V. Fonin
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Russian Academy of Sciences, St. Petersburg 194064, Russia; (E.Y.S.); (E.A.S.); (I.M.K.); (K.K.T.)
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Hoffmann C, Milovanovic D. Dipping contacts - a novel type of contact site at the interface between membraneless organelles and membranes. J Cell Sci 2023; 136:jcs261413. [PMID: 38149872 PMCID: PMC10785658 DOI: 10.1242/jcs.261413] [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] [Indexed: 12/28/2023] Open
Abstract
Liquid-liquid phase separation is a major mechanism for organizing macromolecules, particularly proteins with intrinsically disordered regions, in compartments not limited by a membrane or a scaffold. The cell can therefore be perceived as a complex emulsion containing many of these membraneless organelles, also referred to as biomolecular condensates, together with numerous membrane-bound organelles. It is currently unclear how such a complex concoction operates to allow for intracellular trafficking, signaling and metabolic processes to occur with high spatiotemporal precision. Based on experimental observations of synaptic vesicle condensates - a membraneless organelle that is in fact packed with membranes - we present here the framework of dipping contacts: a novel type of contact site between membraneless organelles and membranes. In this Hypothesis, we propose that our framework of dipping contacts can serve as a foundation to investigate the interface that couples the diffusion and material properties of condensates to biochemical processes occurring in membranes. The identity and regulation of this interface is especially critical in the case of neurodegenerative diseases, where aberrant inclusions of misfolded proteins and damaged organelles underlie cellular pathology.
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Affiliation(s)
- Christian Hoffmann
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
- Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
- Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA
- National Center for X-ray Tomography, Advanced Light Source, Berkeley, CA 94720, USA
- Einstein Center for Neuroscience, Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität Berlin and Berlin Institute of Health, 10117 Berlin, Germany
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40
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Mehta N, Mondal S, Watson ET, Cui Q, Chapman ER. The juxtamembrane linker of synaptotagmin 1 regulates Ca 2+ binding via liquid-liquid phase separation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.11.551903. [PMID: 37609296 PMCID: PMC10441399 DOI: 10.1101/2023.08.11.551903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Synaptotagmin (syt) 1, a Ca2+ sensor for synaptic vesicle exocytosis, functions in vivo as a multimer. Syt1 senses Ca2+ via tandem C2-domains that are connected to a single transmembrane domain via a juxtamembrane linker. Here, we show that this linker segment harbors a lysine-rich, intrinsically disordered region that is necessary and sufficient to mediate liquid-liquid phase separation (LLPS). Interestingly, condensate formation negatively regulates the Ca2+-sensitivity of syt1. Moreover, Ca2+ and anionic phospholipids facilitate the observed phase separation, and increases in [Ca2+]i promote the fusion of syt1 droplets in living cells. Together, these observations suggest a condensate-mediated feedback loop that serves to fine-tune the ability of syt1 to trigger release, via alterations in Ca2+ binding activity and potentially through the impact of LLPS on membrane curvature during fusion reactions. In summary, the juxtamembrane linker of syt1 emerges as a regulator of syt1 function by driving self-association via LLPS.
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Affiliation(s)
- Nikunj Mehta
- Howard Hughes Medical Institute, Department of Neuroscience, University of Wisconsin–Madison, Madison, WI 53705, United States
| | - Sayantan Mondal
- Department of Chemistry, Boston University, Boston, MA 02215, United States
| | - Emma T. Watson
- Howard Hughes Medical Institute, Department of Neuroscience, University of Wisconsin–Madison, Madison, WI 53705, United States
| | - Qiang Cui
- Department of Chemistry, Boston University, Boston, MA 02215, United States
| | - Edwin R. Chapman
- Howard Hughes Medical Institute, Department of Neuroscience, University of Wisconsin–Madison, Madison, WI 53705, United States
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41
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Voß Y, Klaus S, Lichti NP, Ganter M, Guizetti J. Malaria parasite centrins can assemble by Ca2+-inducible condensation. PLoS Pathog 2023; 19:e1011899. [PMID: 38150475 PMCID: PMC10775985 DOI: 10.1371/journal.ppat.1011899] [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: 10/08/2023] [Revised: 01/09/2024] [Accepted: 12/13/2023] [Indexed: 12/29/2023] Open
Abstract
Centrins are small calcium-binding proteins that have a variety of roles and are universally associated with eukaryotic centrosomes. Rapid proliferation of the malaria-causing parasite Plasmodium falciparum in the human blood depends on a particularly divergent and acentriolar centrosome, which incorporates several essential centrins. Their precise mode of action, however, remains unclear. In this study calcium-inducible liquid-liquid phase separation is revealed as an evolutionarily conserved principle of assembly for multiple centrins from P. falciparum and other species. Furthermore, the disordered N-terminus and calcium-binding motifs are defined as essential features for reversible biomolecular condensation, and we demonstrate that certain centrins can form co-condensates. In vivo analysis using live cell STED microscopy shows liquid-like dynamics of centrosomal centrin. Additionally, implementation of an inducible protein overexpression system reveals concentration-dependent formation of extra-centrosomal centrin assemblies with condensate-like properties. The timing of foci formation and dissolution suggests that centrin assembly is regulated. This study thereby provides a new model for centrin accumulation at eukaryotic centrosomes.
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Affiliation(s)
- Yannik Voß
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
- German Center for Infection Research, partner site Heidelberg, Heidelberg, Germany
| | - Severina Klaus
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
- Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - Nicolas P. Lichti
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Markus Ganter
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Julien Guizetti
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
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42
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Wilfling F, Kaksonen M, Stachowiak J. Protein condensates as flexible platforms for membrane traffic. Curr Opin Cell Biol 2023; 85:102258. [PMID: 37832166 PMCID: PMC11165926 DOI: 10.1016/j.ceb.2023.102258] [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: 04/30/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 10/15/2023]
Abstract
With an essential role in nearly every physiological process and disease state, trafficking vesicles are fundamental to cell biology. Canonical understanding of membrane traffic has been driven by key achievements in structural biology. Nonetheless, discoveries over the past few years progressively point to the critical role of intrinsically disordered domains and proteins, which lack a well-defined secondary structure. From the initiation of endocytosis and the sequestration of synaptic vesicles to the stabilization of endoplasmic reticulum exit sites and the extension of the autophagic cup, flexible protein condensates, rich in intrinsic disorder, are increasingly implicated. While important debates about the physical nature and mechanistic interpretation of these findings remain, the significance of transient, multivalent protein assemblies in membrane traffic is increasingly clear.
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Affiliation(s)
- Florian Wilfling
- Max Planck Institute of Biophysics, Mechanisms of Cellular Quality Control, Frankfurt a. M., Germany.
| | - Marko Kaksonen
- University of Geneva, Department of Biochemistry, Geneva, Switzerland.
| | - Jeanne Stachowiak
- University of Texas at Austin, Department of Biomedical Engineering, USA; University of Texas at Austin, Department of Chemical Engineering, USA.
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43
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Cai L, Wang GG. Through the lens of phase separation: intrinsically unstructured protein and chromatin looping. Nucleus 2023; 14:2179766. [PMID: 36821650 PMCID: PMC9980480 DOI: 10.1080/19491034.2023.2179766] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
The establishment, maintenance and dynamic regulation of three-dimensional (3D) chromatin structures provide an important means for partitioning of genome into functionally distinctive domains, which helps to define specialized gene expression programs associated with developmental stages and cell types. Increasing evidence supports critical roles for intrinsically disordered regions (IDRs) harbored within transcription factors (TFs) and chromatin-modulatory proteins in inducing phase separation, a phenomenon of forming membrane-less condensates through partitioning of biomolecules. Such a process is also critically involved in the establishment of high-order chromatin structures and looping. IDR- and phase separation-driven 3D genome (re)organization often goes wrong in disease such as cancer. This review discusses about recent advances in understanding how phase separation of intrinsically disordered proteins (IDPs) modulates chromatin looping and gene expression.
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Affiliation(s)
- Ling Cai
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,Department of Genetics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,Ling Cai Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC27599, USA
| | - Gang Greg Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA,CONTACT Gang Greg Wang Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC27599, USA
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44
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Weinmann R, Frank L, Rippe K. Approaches to characterize chromatin subcompartment organization in the cell nucleus. Curr Opin Struct Biol 2023; 83:102695. [PMID: 37722292 DOI: 10.1016/j.sbi.2023.102695] [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: 06/14/2023] [Revised: 08/05/2023] [Accepted: 08/07/2023] [Indexed: 09/20/2023]
Abstract
The mechanism of self-organization of chromatin subcompartments on the 0.1-1 μm scale and their impact on genome-associated activities has long been a key aspect of research on nuclear organization. Understanding the underlying structure-function relationship, however, remains challenging due to the complex hierarchical structure of chromatin and the polymorphic organization of subcompartments that assemble around it. Towards this goal, approaches to measure local properties and compositional dynamics of chromatin in its endogenous cellular environment are instrumental. Here, we discuss recent advancements in studying these features and their functional implications in protein and RNA enrichment and genome accessibility.
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Affiliation(s)
- Robin Weinmann
- German Cancer Research Center (DKFZ) Heidelberg, Division of Chromatin Networks, Germany; Center for Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), Heidelberg University, Germany; Faculty of Biosciences, Heidelberg University, Germany
| | - Lukas Frank
- German Cancer Research Center (DKFZ) Heidelberg, Division of Chromatin Networks, Germany; Center for Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), Heidelberg University, Germany
| | - Karsten Rippe
- German Cancer Research Center (DKFZ) Heidelberg, Division of Chromatin Networks, Germany; Center for Quantitative Analysis of Molecular and Cellular Biosystems (BioQuant), Heidelberg University, Germany.
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45
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Demmerle J, Hao S, Cai D. Transcriptional condensates and phase separation: condensing information across scales and mechanisms. Nucleus 2023; 14:2213551. [PMID: 37218279 PMCID: PMC10208215 DOI: 10.1080/19491034.2023.2213551] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 04/26/2023] [Accepted: 05/10/2023] [Indexed: 05/24/2023] Open
Abstract
Transcription is the fundamental process of gene expression, which in eukaryotes occurs within the complex physicochemical environment of the nucleus. Decades of research have provided extreme detail in the molecular and functional mechanisms of transcription, but the spatial and genomic organization of transcription remains mysterious. Recent discoveries show that transcriptional components can undergo phase separation and create distinct compartments inside the nucleus, providing new models through which to view the transcription process in eukaryotes. In this review, we focus on transcriptional condensates and their phase separation-like behaviors. We suggest differentiation between physical descriptions of phase separation and the complex and dynamic biomolecular assemblies required for productive gene expression, and we discuss how transcriptional condensates are central to organizing the three-dimensional genome across spatial and temporal scales. Finally, we map approaches for therapeutic manipulation of transcriptional condensates and ask what technical advances are needed to understand transcriptional condensates more completely.
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Affiliation(s)
- Justin Demmerle
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Siyuan Hao
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Danfeng Cai
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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46
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Silonov SA, Smirnov EY, Kuznetsova IM, Turoverov KK, Fonin AV. PML Body Biogenesis: A Delicate Balance of Interactions. Int J Mol Sci 2023; 24:16702. [PMID: 38069029 PMCID: PMC10705990 DOI: 10.3390/ijms242316702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
PML bodies are subnuclear protein complexes that play a crucial role in various physiological and pathological cellular processes. One of the general structural proteins of PML bodies is a member of the tripartite motif (TRIM) family-promyelocytic leukemia protein (PML). It is known that PML interacts with over a hundred partners, and the protein itself is represented by several major isoforms, differing in their variable and disordered C-terminal end due to alternative splicing. Despite nearly 30 years of research, the mechanisms underlying PML body formation and the role of PML proteins in this process remain largely unclear. In this review, we examine the literature and highlight recent progress in this field, with a particular focus on understanding the role of individual domains of the PML protein, its post-translational modifications, and polyvalent nonspecific interactions in the formation of PML bodies. Additionally, based on the available literature, we propose a new hypothetical model of PML body formation.
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Affiliation(s)
- Sergey A. Silonov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russia; (E.Y.S.); (I.M.K.); (K.K.T.)
| | | | | | | | - Alexander V. Fonin
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russia; (E.Y.S.); (I.M.K.); (K.K.T.)
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47
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Yang S, Palmquist KH, Nathan L, Pfeifer CR, Schultheiss PJ, Sharma A, Kam LC, Miller PW, Shyer AE, Rodrigues AR. Morphogens enable interacting supracellular phases that generate organ architecture. Science 2023; 382:eadg5579. [PMID: 37995219 DOI: 10.1126/science.adg5579] [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: 01/26/2023] [Accepted: 09/27/2023] [Indexed: 11/25/2023]
Abstract
During vertebrate organogenesis, increases in morphological complexity are tightly coupled to morphogen expression. In this work, we studied how morphogens influence self-organizing processes at the collective or "supra"-cellular scale in avian skin. We made physical measurements across length scales, which revealed morphogen-enabled material property differences that were amplified at supracellular scales in comparison to cellular scales. At the supracellular scale, we found that fibroblast growth factor (FGF) promoted "solidification" of tissues, whereas bone morphogenetic protein (BMP) promoted fluidity and enhanced mechanical activity. Together, these effects created basement membrane-less compartments within mesenchymal tissue that were mechanically primed to drive avian skin tissue budding. Understanding this multiscale process requires the ability to distinguish between proximal effects of morphogens that occur at the cellular scale and their functional effects, which emerge at the supracellular scale.
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Affiliation(s)
- Sichen Yang
- Laboratory of Morphogenesis, The Rockefeller University, New York, NY 10065, USA
| | - Karl H Palmquist
- Laboratory of Morphogenesis, The Rockefeller University, New York, NY 10065, USA
| | - Levy Nathan
- Laboratory of Morphogenesis, The Rockefeller University, New York, NY 10065, USA
| | - Charlotte R Pfeifer
- Laboratory of Morphogenesis, The Rockefeller University, New York, NY 10065, USA
| | - Paula J Schultheiss
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Anurag Sharma
- Electron Microscopy Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - Lance C Kam
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Pearson W Miller
- Center for Computational Biology, Flatiron Institute, New York, NY 10010, USA
| | - Amy E Shyer
- Laboratory of Morphogenesis, The Rockefeller University, New York, NY 10065, USA
| | - Alan R Rodrigues
- Laboratory of Morphogenesis, The Rockefeller University, New York, NY 10065, USA
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48
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de Souza JP, Stone HA. Protein condensation regulates water availability in cells. Nature 2023; 623:698-699. [PMID: 37853191 DOI: 10.1038/d41586-023-03098-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
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49
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Hamali B, Amine AAA, Al-Sady B. Regulation of the heterochromatin spreading reaction by trans-acting factors. Open Biol 2023; 13:230271. [PMID: 37935357 PMCID: PMC10645111 DOI: 10.1098/rsob.230271] [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: 08/10/2023] [Accepted: 10/03/2023] [Indexed: 11/09/2023] Open
Abstract
Heterochromatin is a gene-repressive protein-nucleic acid ultrastructure that is initially nucleated by DNA sequences. However, following nucleation, heterochromatin can then propagate along the chromatin template in a sequence-independent manner in a reaction termed spreading. At the heart of this process are enzymes that deposit chemical information on chromatin, which attracts the factors that execute chromatin compaction and transcriptional or co/post-transcriptional gene silencing. Given that these enzymes deposit guiding chemical information on chromatin they are commonly termed 'writers'. While the processes of nucleation and central actions of writers have been extensively studied and reviewed, less is understood about how the spreading process is regulated. We discuss how the chromatin substrate is prepared for heterochromatic spreading, and how trans-acting factors beyond writer enzymes regulate it. We examine mechanisms by which trans-acting factors in Suv39, PRC2, SETDB1 and SIR writer systems regulate spreading of the respective heterochromatic marks across chromatin. While these systems are in some cases evolutionarily and mechanistically quite distant, common mechanisms emerge which these trans-acting factors exploit to tune the spreading reaction.
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Affiliation(s)
- Bulut Hamali
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
- The G. W. Hooper Foundation, San Francisco, CA 94143, USA
- College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Ahmed A A Amine
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
- The G. W. Hooper Foundation, San Francisco, CA 94143, USA
| | - Bassem Al-Sady
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
- The G. W. Hooper Foundation, San Francisco, CA 94143, USA
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Zhang L, Xu J, Li M, Chen X. The role of long noncoding RNAs in liquid-liquid phase separation. Cell Signal 2023; 111:110848. [PMID: 37557974 DOI: 10.1016/j.cellsig.2023.110848] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/03/2023] [Accepted: 08/06/2023] [Indexed: 08/11/2023]
Abstract
Long noncoding RNAs (lncRNAs), which are among the most well-characterized noncoding RNAs, have attracted much attention due to their regulatory functions and potential therapeutic options in many types of disease. Liquid-liquid phase separation (LLPS), the formation of droplet condensates, is involved in various cellular processes, but the molecular interactions of lncRNAs in LLPS are unclear. In this review, we describe the research development on LLPS, including descriptions of various methods established to identify LLPS, summarize the physiological and pathological functions of LLPS, identify the molecular interactions of lncRNAs in LLPS, and present the potential applications of leveraging LLPS in the clinic. The aim of this review is to update the knowledge on the association between LLPS and lncRNAs, which might provide a new direction for the treatment of LLPS-mediated disease.
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Affiliation(s)
- Le Zhang
- Center for Reproductive Medicine, The Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, Inner Mongolia, China
| | - Jinjin Xu
- Department of Imaging Medicine, The People's Hospital of the Inner Mongolia Autonomous Region, Hohhot 010017, Inner Mongolia, China
| | - Muxuan Li
- The First Clinical Medical College of Inner Mongolia Medical University, Hohhot 010050, Inner Mongolia, China
| | - Xiujuan Chen
- Center for Reproductive Medicine, The Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, Inner Mongolia, China.
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