1
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Jo M, Kim S, Park J, Chang YT, Gwon Y. Reduced dynamicity and increased high-order protein assemblies in dense fibrillar component of the nucleolus under cellular senescence. Redox Biol 2024; 75:103279. [PMID: 39111063 PMCID: PMC11347067 DOI: 10.1016/j.redox.2024.103279] [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: 05/14/2024] [Revised: 06/27/2024] [Accepted: 07/20/2024] [Indexed: 08/23/2024] Open
Abstract
Cellular senescence, which is triggered by various stressors, manifests as irreversible cell cycle arrest, resulting in the disruption of multiple nuclear condensates. One of the affected structures is the nucleolus, whose tripartite layout, separated into distinct liquid phases, allows for the stepwise progression of ribosome biogenesis. The dynamic properties of dense fibrillar components, a sub-nucleolar phase, are crucial for mediating pre-rRNA processing. However, the mechanistic link between the material properties of dense fibrillar components and cellular senescence remains unclear. We established a significant association between cellular senescence and alterations in nucleolar materiality and characteristics, including the number, size, and sphericity of individual subphases of the nucleolus. Senescent cells exhibit reduced fibrillarin dynamics, aberrant accumulation of high-order protein assemblies, such as oligomers and fibrils, and increased dense fibrillar component density. Intriguingly, the addition of RNA-interacting entities mirrored the diminished diffusion of fibrillarin in the nucleolus during cellular senescence. Thus, our findings contribute to a broader understanding of the intricate changes in the materiality of the nucleolus associated with cellular senescence and shed light on nucleolar dynamics in the context of aging and cellular stress.
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Affiliation(s)
- Minjeong Jo
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea
| | - Soomin Kim
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea
| | - Jeongeun Park
- Department of MetaBioHealth, Sungkyunkwan University Institute for Convergence, Suwon, 16419, Republic of Korea
| | - Young-Tae Chang
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Youngdae Gwon
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea; Department of MetaBioHealth, Sungkyunkwan University Institute for Convergence, Suwon, 16419, Republic of Korea; KIST-SKKU Brain Research Center, Sungkyunkwan University Institute for Convergence, Suwon, 16419, Republic of Korea.
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2
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Niu Z, Gui X, Feng S, Reif B. Aggregation Mechanisms and Molecular Structures of Amyloid-β in Alzheimer's Disease. Chemistry 2024; 30:e202400277. [PMID: 38888453 DOI: 10.1002/chem.202400277] [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] [Revised: 06/13/2024] [Accepted: 06/17/2024] [Indexed: 06/20/2024]
Abstract
Amyloid plaques are a major pathological hallmark involved in Alzheimer's disease and consist of deposits of the amyloid-β peptide (Aβ). The aggregation process of Aβ is highly complex, which leads to polymorphous aggregates with different structures. In addition to aberrant aggregation, Aβ oligomers can undergo liquid-liquid phase separation (LLPS) and form dynamic condensates. It has been hypothesized that these amyloid liquid droplets affect and modulate amyloid fibril formation. In this review, we briefly introduce the relationship between stress granules and amyloid protein aggregation that is associated with neurodegenerative diseases. Then we highlight the regulatory role of LLPS in Aβ aggregation and discuss the potential relationship between Aβ phase transition and aggregation. Furthermore, we summarize the current structures of Aβ oligomers and amyloid fibrils, which have been determined using nuclear magnetic resonance (NMR) and cryo-electron microscopy (cryo-EM). The structural variations of Aβ aggregates provide an explanation for the different levels of toxicity, shed light on the aggregation mechanism and may pave the way towards structure-based drug design for both clinical diagnosis and treatment.
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Affiliation(s)
- Zheng Niu
- School of Pharmacy, Henan University, Kaifeng, Henan, 475004, China
| | - Xinrui Gui
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Shuang Feng
- School of Pharmacy, Henan University, Kaifeng, Henan, 475004, China
| | - Bernd Reif
- Bavarian NMR Center (B NMRZ), Department of Bioscience, TUM School of Natural Sciences, Technische Universität München (TUM), Garching, 85747, Germany
- Institute of Structural Biology (STB), Helmholtz-Zentrum, München (HMGU), Neuherberg, 85764, Germany
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3
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Castelletto V, Seitsonen J, Pollitt A, Hamley IW. Minimal Peptide Sequences That Undergo Liquid-Liquid Phase Separation via Self-Coacervation or Complex Coacervation with ATP. Biomacromolecules 2024; 25:5321-5331. [PMID: 39066731 PMCID: PMC11323023 DOI: 10.1021/acs.biomac.4c00738] [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: 05/31/2024] [Revised: 07/23/2024] [Accepted: 07/23/2024] [Indexed: 07/30/2024]
Abstract
The simple (self-)coacervation of the minimal tryptophan/arginine peptide sequences W2R2 and W3R3 was observed in salt-free aqueous solution. The phase diagrams were mapped using turbidimetry and optical microscopy, and the coacervate droplets were imaged using confocal microscopy complemented by cryo-TEM to image smaller droplets. The droplet size distribution and stability were probed using dynamic light scattering, and the droplet surface potential was obtained from zeta potential measurements. SAXS was used to elucidate the structure within the coacervate droplets, and circular dichroism spectroscopy was used to probe the conformation of the peptides, a characteristic signature for cation-π interactions being present under conditions of coacervation. These observations were rationalized using a simple model for the Rayleigh stability of charged coacervate droplets, along with atomistic molecular dynamics simulations which provide insight into stabilizing π-π stacking interactions of tryptophan as well as arginine-tryptophan cation-π interactions (which modulate the charge of the tryptophan π-electron system). Remarkably, the dipeptide WR did not show simple coacervation under the conditions examined, but complex coacervation was observed in mixtures with ATP (adenosine triphosphate). The electrostatically stabilized coacervation in this case provides a minimal model for peptide/nucleotide membraneless organelle formation. These are among the simplest model peptide systems observed to date able to undergo either simple or complex coacervation and are of future interest as protocell systems.
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Affiliation(s)
- Valeria Castelletto
- School
of Chemistry, Food Biosciences and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K.
| | - Jani Seitsonen
- Nanomicroscopy
Center, Aalto University, Puumiehenkuja 2, Espoo 02150, Finland
| | - Alice Pollitt
- Institute
for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading RG6 6AS, U.K.
| | - Ian W. Hamley
- School
of Chemistry, Food Biosciences and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, U.K.
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4
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Zhou HX, Kota D, Qin S, Prasad R. Fundamental Aspects of Phase-Separated Biomolecular Condensates. Chem Rev 2024; 124:8550-8595. [PMID: 38885177 PMCID: PMC11260227 DOI: 10.1021/acs.chemrev.4c00138] [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: 06/20/2024]
Abstract
Biomolecular condensates, formed through phase separation, are upending our understanding in much of molecular, cell, and developmental biology. There is an urgent need to elucidate the physicochemical foundations of the behaviors and properties of biomolecular condensates. Here we aim to fill this need by writing a comprehensive, critical, and accessible review on the fundamental aspects of phase-separated biomolecular condensates. We introduce the relevant theoretical background, present the theoretical basis for the computation and experimental measurement of condensate properties, and give mechanistic interpretations of condensate behaviors and properties in terms of interactions at the molecular and residue levels.
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Affiliation(s)
- Huan-Xiang Zhou
- Department of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, USA
- Department of Physics, University of Illinois Chicago, Chicago, Illinois 60607, USA
| | - Divya Kota
- Department of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, USA
| | - Sanbo Qin
- Department of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, USA
| | - Ramesh Prasad
- Department of Chemistry, University of Illinois Chicago, Chicago, Illinois 60607, USA
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5
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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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6
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Tsoi PS, Ferreon JC, Ferreon ACM. Initiation of hnRNPA1 Low-Complexity Domain Condensation Monitored by Dynamic Light Scattering. Int J Mol Sci 2024; 25:6825. [PMID: 38999934 PMCID: PMC11241569 DOI: 10.3390/ijms25136825] [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: 05/10/2024] [Revised: 06/14/2024] [Accepted: 06/18/2024] [Indexed: 07/14/2024] Open
Abstract
Biomolecular condensates (BMCs) exhibit physiological and pathological relevance in biological systems. Both liquid and solid condensates play significant roles in the spatiotemporal regulation and organization of macromolecules and their biological activities. Some pathological solid condensates, such as Lewy Bodies and other fibrillar aggregates, have been hypothesized to originate from liquid condensates. With the prevalence of BMCs having functional and dysfunctional roles, it is imperative to understand the mechanism of biomolecular condensate formation and initiation. Using the low-complexity domain (LCD) of heterogenous ribonuclear protein A1 (hnRNPA1) as our model, we monitored initial assembly events using dynamic light scattering (DLS) while modulating pH and salt conditions to perturb macromolecule and condensate properties. We observed the formation of nanometer-sized BMCs (nano-condensates) distinct from protein monomers and micron-sized condensates. We also observed that conditions that solubilize micron-sized protein condensates do not solubilize nano-condensates, indicating that the balance of forces that stabilize nano-condensates and micron-sized condensates are distinct. These findings provide insight into the forces that drive protein phase separation and potential nucleation structures of macromolecular condensation.
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Affiliation(s)
| | - Josephine C. Ferreon
- Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Allan Chris M. Ferreon
- Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA
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7
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Fukata Y, Fukata M, MacGillavry HD, Nair D, Hosy E. Celebrating the Birthday of AMPA Receptor Nanodomains: Illuminating the Nanoscale Organization of Excitatory Synapses with 10 Nanocandles. J Neurosci 2024; 44:e2104232024. [PMID: 38839340 PMCID: PMC11154862 DOI: 10.1523/jneurosci.2104-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 06/07/2024] Open
Abstract
A decade ago, in 2013, and over the course of 4 summer months, three separate observations were reported that each shed light independently on a new molecular organization that fundamentally reshaped our perception of excitatory synaptic transmission (Fukata et al., 2013; MacGillavry et al., 2013; Nair et al., 2013). This discovery unveiled an intricate arrangement of AMPA-type glutamate receptors and their principal scaffolding protein PSD-95, at synapses. This breakthrough was made possible, thanks to advanced super-resolution imaging techniques. It fundamentally changed our understanding of excitatory synaptic architecture and paved the way for a brand-new area of research. In this Progressions article, the primary investigators of the nanoscale organization of synapses have come together to chronicle the tale of their discovery. We recount the initial inquiry that prompted our research, the preceding studies that inspired our work, the technical obstacles that were encountered, and the breakthroughs that were made in the subsequent decade in the realm of nanoscale synaptic transmission. We review the new discoveries made possible by the democratization of super-resolution imaging techniques in the field of excitatory synaptic physiology and architecture, first by the extension to other glutamate receptors and to presynaptic proteins and then by the notion of trans-synaptic organization. After describing the organizational modifications occurring in various pathologies, we discuss briefly the latest technical developments made possible by super-resolution imaging and emerging concepts in synaptic physiology.
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Affiliation(s)
- Yuko Fukata
- Division of Molecular and Cellular Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Masaki Fukata
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Division of Neuropharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
- Department of Physiological Sciences, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Harold D MacGillavry
- Division of Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, The Netherlands
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Eric Hosy
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, CNRS UMR5297, Bordeaux F-33000, France
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8
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Mukherjee S, Poudyal M, Dave K, Kadu P, Maji SK. Protein misfolding and amyloid nucleation through liquid-liquid phase separation. Chem Soc Rev 2024; 53:4976-5013. [PMID: 38597222 DOI: 10.1039/d3cs01065a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Liquid-liquid phase separation (LLPS) is an emerging phenomenon in cell physiology and diseases. The weak multivalent interaction prerequisite for LLPS is believed to be facilitated through intrinsically disordered regions, which are prevalent in neurodegenerative disease-associated proteins. These aggregation-prone proteins also exhibit an inherent property for phase separation, resulting in protein-rich liquid-like droplets. The very high local protein concentration in the water-deficient confined microenvironment not only drives the viscoelastic transition from the liquid to solid-like state but also most often nucleate amyloid fibril formation. Indeed, protein misfolding, oligomerization, and amyloid aggregation are observed to be initiated from the LLPS of various neurodegeneration-related proteins. Moreover, in these cases, neurodegeneration-promoting genetic and environmental factors play a direct role in amyloid aggregation preceded by the phase separation. These cumulative recent observations ignite the possibility of LLPS being a prominent nucleation mechanism associated with aberrant protein aggregation. The present review elaborates on the nucleation mechanism of the amyloid aggregation pathway and the possible early molecular events associated with amyloid-related protein phase separation. It also summarizes the recent advancement in understanding the aberrant phase transition of major proteins contributing to neurodegeneration focusing on the common disease-associated factors. Overall, this review proposes a generic LLPS-mediated multistep nucleation mechanism for amyloid aggregation and its implication in neurodegeneration.
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Affiliation(s)
- Semanti Mukherjee
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Manisha Poudyal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Kritika Dave
- Sunita Sanghi Centre of Aging and Neurodegenerative Diseases, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Pradeep Kadu
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Samir K Maji
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
- Sunita Sanghi Centre of Aging and Neurodegenerative Diseases, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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9
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Warnock JL, Ball JA, Najmi SM, Henes M, Vazquez A, Koshnevis S, Wieden HJ, Conn GL, Ghalei H. Differential roles of putative arginine fingers of AAA + ATPases Rvb1 and Rvb2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.593962. [PMID: 38798342 PMCID: PMC11118528 DOI: 10.1101/2024.05.13.593962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The evolutionarily conserved AAA+ ATPases Rvb1 and Rvb2 proteins form a heteromeric complex (Rvb1/2) required for assembly or remodeling of macromolecular complexes in essential cellular processes ranging from chromatin remodeling to ribosome biogenesis. Rvb1 and Rvb2 have a high degree of sequence and structural similarity, and both contain the classical features of ATPases of their clade, including an N-terminal AAA+ subdomain with the Walker A motif, an insertion domain that typically interacts with various binding partners, and a C-terminal AAA+ subdomain containing a Walker B motif, the Sensor I and II motifs, and an arginine finger. In this study, we find that despite the high degree of structural similarity, Rvb1 and Rvb2 have distinct active sites that impact their activities and regulation within the Rvb1/2 complex. Using a combination of biochemical and genetic approaches, we show that replacing the homologous arginine fingers of Rvb1 and Rvb2 with different amino acids not only has distinct effects on the catalytic activity of the complex, but also impacts cell growth, and the Rvb1/2 interactions with binding partners. Using molecular dynamics simulations, we find that changes near the active site of Rvb1 and Rvb2 cause long-range effects on the protein dynamics in the insertion domain, suggesting a molecular basis for how enzymatic activity within the catalytic site of ATP hydrolysis can be relayed to other domains of the Rvb1/2 complex to modulate its function. Further, we show the impact that the arginine finger variants have on snoRNP biogenesis and validate the findings from molecular dynamics simulations using a targeted genetic screen. Together, our results reveal new aspects of the regulation of the Rvb1/2 complex by identifying a relay of long-range molecular communication from the ATPase active site of the complex to the binding site of cofactors. Most importantly, our findings suggest that despite high similarity and cooperation within the same protein complex, the two proteins have evolved with unique properties critical for the regulation and function of the Rvb1/2 complex.
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Affiliation(s)
- Jennifer L. Warnock
- Emory University School of Medicine, Department of Biochemistry, Atlanta, Georgia, USA
| | - Jacob A. Ball
- Emory University School of Medicine, Department of Biochemistry, Atlanta, Georgia, USA
| | - Saman M. Najmi
- Emory University School of Medicine, Department of Biochemistry, Atlanta, Georgia, USA
| | - Mina Henes
- Emory University School of Medicine, Department of Biochemistry, Atlanta, Georgia, USA
- Graduate Program in Biochemistry, Cell & Developmental Biology (BCDB), Emory University, Atlanta, Georgia, USA
- Medical Scientist Training Program, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Amanda Vazquez
- Department of Microbiology, Faculty of Science, University of Manitoba, Manitoba, Canada
| | - Sohail Koshnevis
- Emory University School of Medicine, Department of Biochemistry, Atlanta, Georgia, USA
| | - Hans-Joachim Wieden
- Department of Microbiology, Faculty of Science, University of Manitoba, Manitoba, Canada
| | - Graeme L. Conn
- Emory University School of Medicine, Department of Biochemistry, Atlanta, Georgia, USA
| | - Homa Ghalei
- Emory University School of Medicine, Department of Biochemistry, Atlanta, Georgia, USA
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10
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Dabirmanesh B, Khajeh K, Uversky VN. The hidden world of protein aggregation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2024; 206:473-494. [PMID: 38811088 DOI: 10.1016/bs.pmbts.2024.03.014] [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: 05/31/2024]
Abstract
Though the book's journey into The Hidden World of Protein Aggregation has come to an end, the search for knowledge, the development of healthier lives, and the discovery of nature's mysteries continue, promising new horizons and discoveries yet to be discovered. The intricacies of protein misfolding and aggregation remain a mystery in cellular biology, despite advances made in unraveling them. In this chapter, we will summarize the specific conclusions from the previous chapters and explore the persistent obstacles and unanswered questions that motivate scientists to pursue exploration of protein misfolding and aggregation.
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Affiliation(s)
- Bahareh Dabirmanesh
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
| | - Khosro Khajeh
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Vladimir N Uversky
- Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Institute for Biological Instrumentation, Pushchino, Moscow, Russia; Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
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11
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Ray S, Buell AK. Emerging experimental methods to study the thermodynamics of biomolecular condensate formation. J Chem Phys 2024; 160:091001. [PMID: 38445729 DOI: 10.1063/5.0190160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/15/2024] [Indexed: 03/07/2024] Open
Abstract
The formation of biomolecular condensates in vivo is increasingly recognized to underlie a multitude of crucial cellular functions. Furthermore, the evolution of highly dynamic protein condensates into progressively less reversible assemblies is thought to be involved in a variety of disorders, from cancer over neurodegeneration to rare genetic disorders. There is an increasing need for efficient experimental methods to characterize the thermodynamics of condensate formation and that can be used in screening campaigns to identify and rationally design condensate modifying compounds. Theoretical advances in the field are also identifying the key parameters that need to be measured in order to obtain a comprehensive understanding of the underlying interactions and driving forces. Here, we review recent progress in the development of efficient and quantitative experimental methods to study the driving forces behind and the temporal evolution of biomolecular condensates.
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Affiliation(s)
- Soumik Ray
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Alexander K Buell
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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12
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Ripin N, Parker R. Formation, function, and pathology of RNP granules. Cell 2023; 186:4737-4756. [PMID: 37890457 PMCID: PMC10617657 DOI: 10.1016/j.cell.2023.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 07/28/2023] [Accepted: 09/07/2023] [Indexed: 10/29/2023]
Abstract
Ribonucleoprotein (RNP) granules are diverse membrane-less organelles that form through multivalent RNA-RNA, RNA-protein, and protein-protein interactions between RNPs. RNP granules are implicated in many aspects of RNA physiology, but in most cases their functions are poorly understood. RNP granules can be described through four key principles. First, RNP granules often arise because of the large size, high localized concentrations, and multivalent interactions of RNPs. Second, cells regulate RNP granule formation by multiple mechanisms including posttranslational modifications, protein chaperones, and RNA chaperones. Third, RNP granules impact cell physiology in multiple manners. Finally, dysregulation of RNP granules contributes to human diseases. Outstanding issues in the field remain, including determining the scale and molecular mechanisms of RNP granule function and how granule dysfunction contributes to human disease.
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Affiliation(s)
- Nina Ripin
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Roy Parker
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80303, USA.
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13
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Hwang HJ, Park TL, Kim HI, Park Y, Kim G, Song C, Cho WK, Kim YK. YTHDF2 facilitates aggresome formation via UPF1 in an m 6A-independent manner. Nat Commun 2023; 14:6248. [PMID: 37803021 PMCID: PMC10558514 DOI: 10.1038/s41467-023-42015-w] [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: 11/15/2022] [Accepted: 09/27/2023] [Indexed: 10/08/2023] Open
Abstract
YTHDF2 has been extensively studied and typified as an RNA-binding protein that specifically recognizes and destabilizes RNAs harboring N6-methyladenosine (m6A), the most prevalent internal modification found in eukaryotic RNAs. In this study, we unravel the m6A-independent role of YTHDF2 in the formation of an aggresome, where cytoplasmic protein aggregates are selectively sequestered upon failure of protein homeostasis mediated by the ubiquitin-proteasome system. Downregulation of YTHDF2 in HeLa cells reduces the circularity of aggresomes and the rate of movement of misfolded polypeptides, inhibits aggresome formation, and thereby promotes cellular apoptosis. Mechanistically, YTHDF2 is recruited to a misfolded polypeptide-associated complex composed of UPF1, CTIF, eEF1A1, and DCTN1 through its interaction with UPF1. Subsequently, YTHDF2 increases the interaction between the dynein motor protein and the misfolded polypeptide-associated complex, facilitating the diffusion dynamics of the movement of misfolded polypeptides toward aggresomes. Therefore, our data reveal that YTHDF2 is a cellular factor involved in protein quality control.
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Affiliation(s)
- Hyun Jung Hwang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Tae Lim Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Hyeong-In Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Yeonkyoung Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Geunhee Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Chiyeol Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Won-Ki Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| | - Yoon Ki Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
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14
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Poudyal M, Patel K, Gadhe L, Sawner AS, Kadu P, Datta D, Mukherjee S, Ray S, Navalkar A, Maiti S, Chatterjee D, Devi J, Bera R, Gahlot N, Joseph J, Padinhateeri R, Maji SK. Intermolecular interactions underlie protein/peptide phase separation irrespective of sequence and structure at crowded milieu. Nat Commun 2023; 14:6199. [PMID: 37794023 PMCID: PMC10550955 DOI: 10.1038/s41467-023-41864-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 09/21/2023] [Indexed: 10/06/2023] Open
Abstract
Liquid-liquid phase separation (LLPS) has emerged as a crucial biological phenomenon underlying the sequestration of macromolecules (such as proteins and nucleic acids) into membraneless organelles in cells. Unstructured and intrinsically disordered domains are known to facilitate multivalent interactions driving protein LLPS. We hypothesized that LLPS could be an intrinsic property of proteins/polypeptides but with distinct phase regimes irrespective of their sequence and structure. To examine this, we studied many (a total of 23) proteins/polypeptides with different structures and sequences for LLPS study in the presence and absence of molecular crowder, polyethylene glycol (PEG-8000). We showed that all proteins and even highly charged polypeptides (under study) can undergo liquid condensate formation, however with different phase regimes and intermolecular interactions. We further demonstrated that electrostatic, hydrophobic, and H-bonding or a combination of such intermolecular interactions plays a crucial role in individual protein/peptide LLPS.
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Affiliation(s)
- Manisha Poudyal
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Komal Patel
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
- Sunita Sanghi Centre of Aging and Neurodegenerative Diseases, IIT Bombay, Powai, Mumbai, 400076, India
| | - Laxmikant Gadhe
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Ajay Singh Sawner
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Pradeep Kadu
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Debalina Datta
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Semanti Mukherjee
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Soumik Ray
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Ambuja Navalkar
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Siddhartha Maiti
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
- Department of Bioengineering, VIT Bhopal University, Bhopal-Indore Highway, Kothrikalan, Sehore, Madhya Pradesh, 466114, India
| | - Debdeep Chatterjee
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Jyoti Devi
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Riya Bera
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Nitisha Gahlot
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Jennifer Joseph
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India
| | - Samir K Maji
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai, 400076, India.
- Sunita Sanghi Centre of Aging and Neurodegenerative Diseases, IIT Bombay, Powai, Mumbai, 400076, India.
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15
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Cardona AH, Ecsedi S, Khier M, Yi Z, Bahri A, Ouertani A, Valero F, Labrosse M, Rouquet S, Robert S, Loubat A, Adekunle D, Hubstenberger A. Self-demixing of mRNA copies buffers mRNA:mRNA and mRNA:regulator stoichiometries. Cell 2023; 186:4310-4324.e23. [PMID: 37703874 DOI: 10.1016/j.cell.2023.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 06/08/2023] [Accepted: 08/16/2023] [Indexed: 09/15/2023]
Abstract
Cellular homeostasis requires the robust control of biomolecule concentrations, but how do millions of mRNAs coordinate their stoichiometries in the face of dynamic translational changes? Here, we identified a two-tiered mechanism controlling mRNA:mRNA and mRNA:protein stoichiometries where mRNAs super-assemble into condensates with buffering capacity and sorting selectivity through phase-transition mechanisms. Using C. elegans oogenesis arrest as a model, we investigated the transcriptome cytosolic reorganization through the sequencing of RNA super-assemblies coupled with single mRNA imaging. Tightly repressed mRNAs self-assembled into same-sequence nanoclusters that further co-assembled into multiphase condensates. mRNA self-sorting was concentration dependent, providing a self-buffering mechanism that is selective to sequence identity and controls mRNA:mRNA stoichiometries. The cooperative sharing of limiting translation repressors between clustered mRNAs prevented the disruption of mRNA:repressor stoichiometries in the cytosol. Robust control of mRNA:mRNA and mRNA:protein stoichiometries emerges from mRNA self-demixing and cooperative super-assembly into multiphase multiscale condensates with dynamic storage capacity.
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Affiliation(s)
| | - Szilvia Ecsedi
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Mokrane Khier
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Zhou Yi
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Alia Bahri
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Amira Ouertani
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Florian Valero
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | | | - Sami Rouquet
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Stéphane Robert
- Université Aix Marseille, Inserm, INRAE, C2VN, 13005 Marseille, France
| | - Agnès Loubat
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
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16
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Tschurikow X, Gadzekpo A, Tran MP, Chatterjee R, Sobucki M, Zaburdaev V, Göpfrich K, Hilbert L. Amphiphiles Formed from Synthetic DNA-Nanomotifs Mimic the Stepwise Dispersal of Transcriptional Clusters in the Cell Nucleus. NANO LETTERS 2023; 23:7815-7824. [PMID: 37586706 PMCID: PMC10510709 DOI: 10.1021/acs.nanolett.3c01301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/28/2023] [Indexed: 08/18/2023]
Abstract
Stem cells exhibit prominent clusters controlling the transcription of genes into RNA. These clusters form by a phase-separation mechanism, and their size and shape are controlled via an amphiphilic effect of transcribed genes. Here, we construct amphiphile-nanomotifs purely from DNA, and we achieve similar size and shape control for phase-separated droplets formed from fully synthetic, self-interacting DNA-nanomotifs. Increasing amphiphile concentrations induce rounding of droplets, prevent droplet fusion, and, at high concentrations, cause full dispersal of droplets. Super-resolution microscopy data obtained from zebrafish embryo stem cells reveal a comparable transition for transcriptional clusters with increasing transcription levels. Brownian dynamics and lattice simulations further confirm that the addition of amphiphilic particles is sufficient to explain the observed changes in shape and size. Our work reproduces key aspects of transcriptional cluster formation in biological cells using relatively simple DNA sequence-programmable nanostructures, opening novel ways to control the mesoscopic organization of synthetic nanomaterials.
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Affiliation(s)
- Xenia Tschurikow
- Institute
of Biological and Chemical Systems, Karlsruhe
Institute of Technology, Eggenstein-Leopoldshafen 76344, Germany
- Zoological
Institute, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany
| | - Aaron Gadzekpo
- Institute
of Biological and Chemical Systems, Karlsruhe
Institute of Technology, Eggenstein-Leopoldshafen 76344, Germany
- Zoological
Institute, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany
| | - Mai P. Tran
- Center
for Molecular Biology of Heidelberg University (ZMBH), Heidelberg 69120, Germany
- Max
Planck Institute for Medical Research, Heidelberg 69120, Germany
| | - Rakesh Chatterjee
- Max
Planck Zentrum für Physik und Medizin, Erlangen 91058, Germany
- Chair
of Mathematics in Life Sciences, Friedrich-Alexander
Universität Erlangen-Nürnberg, Erlangen 91058, Germany
| | - Marcel Sobucki
- Institute
of Biological and Chemical Systems, Karlsruhe
Institute of Technology, Eggenstein-Leopoldshafen 76344, Germany
| | - Vasily Zaburdaev
- Max
Planck Zentrum für Physik und Medizin, Erlangen 91058, Germany
- Chair
of Mathematics in Life Sciences, Friedrich-Alexander
Universität Erlangen-Nürnberg, Erlangen 91058, Germany
| | - Kerstin Göpfrich
- Center
for Molecular Biology of Heidelberg University (ZMBH), Heidelberg 69120, Germany
- Max
Planck Institute for Medical Research, Heidelberg 69120, Germany
| | - Lennart Hilbert
- Institute
of Biological and Chemical Systems, Karlsruhe
Institute of Technology, Eggenstein-Leopoldshafen 76344, Germany
- Zoological
Institute, Karlsruhe Institute of Technology, Karlsruhe 76131, Germany
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17
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Lan C, Kim J, Ulferts S, Aprile-Garcia F, Weyrauch S, Anandamurugan A, Grosse R, Sawarkar R, Reinhardt A, Hugel T. Quantitative real-time in-cell imaging reveals heterogeneous clusters of proteins prior to condensation. Nat Commun 2023; 14:4831. [PMID: 37582808 PMCID: PMC10427612 DOI: 10.1038/s41467-023-40540-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023] Open
Abstract
Our current understanding of biomolecular condensate formation is largely based on observing the final near-equilibrium condensate state. Despite expectations from classical nucleation theory, pre-critical protein clusters were recently shown to form under subsaturation conditions in vitro; if similar long-lived clusters comprising more than a few molecules are also present in cells, our understanding of the physical basis of biological phase separation may fundamentally change. Here, we combine fluorescence microscopy with photobleaching analysis to quantify the formation of clusters of NELF proteins in living, stressed cells. We categorise small and large clusters based on their dynamics and their response to p38 kinase inhibition. We find a broad distribution of pre-condensate cluster sizes and show that NELF protein cluster formation can be explained as non-classical nucleation with a surprisingly flat free-energy landscape for a wide range of sizes and an inhibition of condensation in unstressed cells.
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Affiliation(s)
- Chenyang Lan
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- BIOSS and CIBSS Signalling Research Centres, University of Freiburg, Freiburg, Germany
- PicoQuant GmbH, Rudower Chaussee 29, 12489, Berlin, Germany
| | - Juhyeong Kim
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
| | - Svenja Ulferts
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | | | - Sophie Weyrauch
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
- Faculty of Chemistry and Pharmacology, University of Freiburg, Freiburg, Germany
| | | | - Robert Grosse
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - Ritwick Sawarkar
- Medical Research Council (MRC), University of Cambridge, Cambridge, CB2 1QR, United Kingdom
| | - Aleks Reinhardt
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom.
| | - Thorsten Hugel
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany.
- BIOSS and CIBSS Signalling Research Centres, University of Freiburg, Freiburg, Germany.
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18
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Abstract
Multivalent proteins and nucleic acids, collectively referred to as multivalent associative biomacromolecules, provide the driving forces for the formation and compositional regulation of biomolecular condensates. Here, we review the key concepts of phase transitions of aqueous solutions of associative biomacromolecules, specifically proteins that include folded domains and intrinsically disordered regions. The phase transitions of these systems come under the rubric of coupled associative and segregative transitions. The concepts underlying these processes are presented, and their relevance to biomolecular condensates is discussed.
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Affiliation(s)
- Rohit V Pappu
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Samuel R Cohen
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Center of Regenerative Medicine, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Furqan Dar
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Mina Farag
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Mrityunjoy Kar
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
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19
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Zhang J, Huang Y, Bai F. Stochastic Monte Carlo Model for Simulating the Dynamic Liquid-Liquid Phase Separation in Bacterial Cells. J Phys Chem B 2023; 127:4145-4153. [PMID: 37130439 DOI: 10.1021/acs.jpcb.3c01696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
There is growing evidence showing that many critical biological processes are driven by biomolecule condensates through liquid-liquid phase separation (LLPS). Although the qualitative observation and description of LLPS have been well documented, quantitative simulations of the time-dependent progression of LLPS in live cells are generally lacking. In this work, we build a stochastic Monte Carlo model to simulate the dynamic LLPS process during the formation of bacterial aggresomes. We demonstrate that the size distribution of the protein condensates evolves from an exponential-like to a bimodal-like pattern, and the number of condensates increases at the beginning and then decreases after reaching a maximum. Incorporating diffusion and collision, our simplified model recapitulates the two-step LLPS process in which many smaller condensates are formed in the first step and then merged into a few larger ones. We further reveal that the condensation speed, which can be defined by the condensates formed in unit time during the first step, is mainly determined by both the collision energy barrier and the initial protein density, while the number of condensates at the equilibrium is mainly associated with the dissociation energy barrier. Moreover, the LLPS process is not sensitive to temperature changes ranging around physiological conditions. Additionally, we consider the effect of the nucleation energy barrier on LLPS. We find that a higher nucleation energy barrier brings a slower condensation speed. Overall, we simulate the spatiotemporal dynamics of the LLPS process and provide qualitative guidance for understanding the dynamics of LLPS in bacterial cells, which can faithfully recapitulate experimental observations and facilitate the design of future experimental tests.
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Affiliation(s)
- Jingpeng Zhang
- Biomedical Pioneering Innovation Center, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Yanyi Huang
- Biomedical Pioneering Innovation Center, Peking University, Beijing 100871, China
- College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
- Institute for Cell Analysis, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Fan Bai
- Biomedical Pioneering Innovation Center, Peking University, Beijing 100871, China
- School of Life Sciences, Peking University, Beijing 100871, China
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20
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Concha-Marambio L, Pritzkow S, Shahnawaz M, Farris CM, Soto C. Seed amplification assay for the detection of pathologic alpha-synuclein aggregates in cerebrospinal fluid. Nat Protoc 2023; 18:1179-1196. [PMID: 36653527 PMCID: PMC10561622 DOI: 10.1038/s41596-022-00787-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 10/10/2022] [Indexed: 01/19/2023]
Abstract
Misfolded alpha-synuclein (αSyn) aggregates are a hallmark event in Parkinson's disease (PD) and other synucleinopathies. Recently, αSyn seed amplification assays (αSyn-SAAs) have shown promise as a test for biochemical diagnosis of synucleinopathies. αSyn-SAAs use the intrinsic self-replicative nature of misfolded αSyn aggregates (seeds) to multiply them in vitro. In these assays, αSyn seeds circulating in biological fluids are amplified by a cyclical process that includes aggregate fragmentation into smaller self-propagating seeds, followed by elongation at the expense of recombinant αSyn (rec-αSyn). Amplification of the seeds allows detection by fluorescent dyes specific for amyloids, such as thioflavin T. Several αSyn-SAA reports have been published in the past under the names 'protein misfolding cyclic amplification' (αSyn-PMCA) and 'real-time quaking-induced conversion'. Here, we describe a protocol for αSyn-SAA, originally reported as αSyn-PMCA, which allows detection of αSyn aggregates in cerebrospinal fluid samples from patients affected by PD, dementia with Lewy bodies or multiple-system atrophy (MSA). Moreover, this αSyn-SAA can differentiate αSyn aggregates from patients with PD versus those from patients with MSA, even in retrospective samples from patients with pure autonomic failure who later developed PD or MSA. We also describe modifications to the original protocol introduced to develop an optimized version of the assay. The optimized version shortens the assay length, decreases the amount of rec-αSyn required and reduces the number of inconclusive results. The protocol has a hands-on time of ~2 h per 96-well plate and can be performed by personnel trained to perform basic experiments with specimens of human origin.
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Affiliation(s)
| | - Sandra Pritzkow
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, University of Texas McGovern Medical School, Houston, TX, USA
| | - Mohammad Shahnawaz
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, University of Texas McGovern Medical School, Houston, TX, USA
| | | | - Claudio Soto
- R&D Unit, Amprion Inc., San Diego, CA, USA.
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, University of Texas McGovern Medical School, Houston, TX, USA.
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21
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Liquid-liquid Phase Separation of α-Synuclein: A New Mechanistic Insight for α-Synuclein Aggregation Associated with Parkinson's Disease Pathogenesis. J Mol Biol 2023; 435:167713. [PMID: 35787838 DOI: 10.1016/j.jmb.2022.167713] [Citation(s) in RCA: 41] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 02/04/2023]
Abstract
Aberrant aggregation of the misfolded presynaptic protein, α-Synuclein (α-Syn) into Lewy body (LB) and Lewy neuritis (LN) is a major pathological hallmark of Parkinson's disease (PD) and other synucleinopathies. Numerous studies have suggested that prefibrillar and fibrillar species of the misfolded α-Syn aggregates are responsible for cell death in PD pathogenesis. However, the precise molecular events during α-Syn aggregation, especially in the early stages, remain elusive. Emerging evidence has demonstrated that liquid-liquid phase separation (LLPS) of α-Syn occurs in the nucleation step of α-Syn aggregation, which offers an alternate non-canonical aggregation pathway in the crowded microenvironment. The liquid-like α-Syn droplets gradually undergo an irreversible liquid-to-solid phase transition into amyloid-like hydrogel entrapping oligomers and fibrils. This new mechanism of α-Syn LLPS and gel formation might represent the molecular basis of cellular toxicity associated with PD. This review aims to demonstrate the recent development of α-Syn LLPS, the underlying mechanism along with the microscopic events of aberrant phase transition. This review further discusses how several intrinsic and extrinsic factors regulate the thermodynamics and kinetics of α-Syn LLPS and co-LLPS with other proteins, which might explain the pathophysiology of α-Syn in various neurodegenerative diseases.
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22
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Ginell GM, Holehouse AS. An Introduction to the Stickers-and-Spacers Framework as Applied to Biomolecular Condensates. Methods Mol Biol 2023; 2563:95-116. [PMID: 36227469 DOI: 10.1007/978-1-0716-2663-4_4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Cellular organization is determined by a combination of membrane-bound and membrane-less biomolecular assemblies that range from clusters of tens of molecules to micrometer-sized cellular bodies. Over the last decade, membrane-less assemblies have come to be referred to as biomolecular condensates, reflecting their ability to condense specific molecules with respect to the remainder of the cell. In many cases, the physics of phase transitions provides a conceptual framework and a mathematical toolkit to describe the assembly, maintenance, and dissolution of biomolecular condensates. Among the various quantitative and qualitative models applied to understand intracellular phase transitions, the stickers-and-spacers framework offers an intuitive yet rigorous means to map biomolecular sequences and structure to the driving forces needed for higher-order assembly. This chapter introduces the fundamental concepts behind the stickers-and-spacers model, considers its application to different biological systems, and discusses limitations and misconceptions around the model.
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Affiliation(s)
- Garrett M Ginell
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
- Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, MO, USA
| | - Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA.
- Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, MO, USA.
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23
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Pandey G, Budhathoki A, Spille JH. Characterizing Properties of Biomolecular Condensates Below the Diffraction Limit In Vivo. Methods Mol Biol 2023; 2563:425-445. [PMID: 36227487 DOI: 10.1007/978-1-0716-2663-4_22] [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] [Indexed: 06/16/2023]
Abstract
Fluorescence microscopy assays enable the investigation of endogenous biomolecular condensates directly in their cellular context. With appropriate experimental designs, these assays yield quantitative information on condensate material properties and inform on biophysical mechanisms of condensate formation. Single-molecule super-resolution and tracking experiments grant access to the smallest condensates and early condensation stages not resolved by conventional imaging approaches. Here, we discuss considerations for using single-molecule assays to extract quantitative information about biomolecular condensates directly in their cellular context.
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Affiliation(s)
- Ganesh Pandey
- Department of Physics, University of Illinois at Chicago, Chicago, IL, USA
| | - Alisha Budhathoki
- Department of Physics, University of Illinois at Chicago, Chicago, IL, USA
| | - Jan-Hendrik Spille
- Department of Physics, University of Illinois at Chicago, Chicago, IL, USA.
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24
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Unravelling the microscopic characteristics of intrinsically disordered proteins upon liquid–liquid phase separation. Essays Biochem 2022; 66:891-900. [DOI: 10.1042/ebc20220148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/13/2022] [Accepted: 11/14/2022] [Indexed: 12/23/2022]
Abstract
Abstract
Biomolecular condensate formation via liquid–liquid phase separation (LLPS) has emerged as a ubiquitous mechanism underlying the spatiotemporal organization of biomolecules in the cell. These membraneless condensates form and disperse dynamically in response to environmental stimuli. Growing evidence indicates that the liquid-like condensates not only play functional physiological roles but are also implicated in a wide range of human diseases. As a major component of biomolecular condensates, intrinsically disordered proteins (IDPs) are intimately involved in the LLPS process. During the last decade, great efforts have been made on the macroscopic characterization of the physicochemical properties and biological functions of liquid condensates both in vitro and in the cellular context. However, characterization of the conformations and interactions at the molecular level within phase-separated condensates is still at an early stage. In the present review, we summarize recent biophysical studies investigating the intramolecular conformational changes of IDPs upon LLPS and the intermolecular clustering of proteins undergoing LLPS, with a particular focus on single-molecule fluorescence detection. We also discuss how these microscopic features are linked to the macroscopic phase transitions that are relevant to the physiological and pathological roles of the condensates.
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25
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Rajeev P, Singh N, Kechkar A, Butler C, Ramanan N, Sibarita JB, Jose M, Nair D. Nanoscale regulation of Ca2+ dependent phase transitions and real-time dynamics of SAP97/hDLG. Nat Commun 2022; 13:4236. [PMID: 35869063 PMCID: PMC9307800 DOI: 10.1038/s41467-022-31912-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 07/08/2022] [Indexed: 11/20/2022] Open
Abstract
Synapse associated protein-97/Human Disk Large (SAP97/hDLG) is a conserved, alternatively spliced, modular, scaffolding protein critical in regulating the molecular organization of cell-cell junctions in vertebrates. We confirm that the molecular determinants of first order phase transition of SAP97/hDLG is controlled by morpho-functional changes in its nanoscale organization. Furthermore, the nanoscale molecular signatures of these signalling islands and phase transitions are altered in response to changes in cytosolic Ca2+. Additionally, exchange kinetics of alternatively spliced isoforms of the intrinsically disordered region in SAP97/hDLG C-terminus shows differential sensitivities to Ca2+ bound Calmodulin, affirming that the molecular signatures of local phase transitions of SAP97/hDLG depends on their nanoscale heterogeneity and compositionality of isoforms. SAP97/hDLG is a ubiquitous, alternatively spliced, and conserved modular scaffolding protein involved in the organization cell junctions and excitatory synapses. Here, authors confirm that SAP97/hDLG condenses in to nanosized molecular domains in both heterologous cells and hippocampal pyramidal neurons. Authors demonstrate that in vivo and in vitro condensation, molecular signatures of nanoscale condensates and exchange kinetics of SAP97/hDLG is modulated by the local availability of alternatively spliced isoforms. Additionally, SAP97/hDLG isoforms exhibits a differential sensitivity to Ca2+ bound Calmodulin, resulting in altered properties of nanocondensates and their real-time regulation
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26
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Phase separation and other forms of α-Synuclein self-assemblies. Essays Biochem 2022; 66:987-1000. [DOI: 10.1042/ebc20220055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022]
Abstract
Abstract
α-Synuclein (α-Syn) is a natively unstructured protein, which self-assembles into higher-order aggregates possessing serious pathophysiological implications. α-Syn aberrantly self-assembles into protein aggregates, which have been widely implicated in Parkinson’s disease (PD) pathogenesis and other synucleinopathies. The self-assembly of α-Syn involves the structural conversion of soluble monomeric protein into oligomeric intermediates and eventually fibrillar aggregates of amyloids with cross-β-sheet rich conformation. These aggregated α-Syn species majorly constitute the intraneuronal inclusions, which is a hallmark of PD neuropathology. Self-assembly/aggregation of α-Syn is not a single-state conversion process as unfolded protein can access multiple conformational states through the formation of metastable, transient pre-fibrillar intermediate species. Recent studies have indicated that soluble oligomers are the potential neurotoxic species responsible for cell death in PD pathogenesis. The heterogeneous and transient nature of oligomers formed during the early stage of aggregation pathway limit their detailed study in understanding the structure–toxicity relationship. Moreover, the precise molecular events occurring in the early stage of α-Syn aggregation process majorly remain unsolved. Recently, liquid–liquid phase separation (LLPS) of α-Syn has been designated as an alternate nucleation mechanism, which occurs in the early lag phase of the aggregation pathway leading to the formation of dynamic supramolecular assemblies. The stronger self-association among the protein molecules triggers the irreversible liquid-to-solid transition of these supramolecular assemblies into the amyloid-like hydrogel, which may serve as a reservoir entrapping toxic oligomeric intermediates and fibrils. This review strives to provide insights into different modes of α-Syn self-assemblies including LLPS-mediated self-assembly and its recent advancements.
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27
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Mitrea DM, Mittasch M, Gomes BF, Klein IA, Murcko MA. Modulating biomolecular condensates: a novel approach to drug discovery. Nat Rev Drug Discov 2022; 21:841-862. [PMID: 35974095 PMCID: PMC9380678 DOI: 10.1038/s41573-022-00505-4] [Citation(s) in RCA: 85] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2022] [Indexed: 12/12/2022]
Abstract
In the past decade, membraneless assemblies known as biomolecular condensates have been reported to play key roles in many cellular functions by compartmentalizing specific proteins and nucleic acids in subcellular environments with distinct properties. Furthermore, growing evidence supports the view that biomolecular condensates often form by phase separation, in which a single-phase system demixes into a two-phase system consisting of a condensed phase and a dilute phase of particular biomolecules. Emerging understanding of condensate function in normal and aberrant cellular states, and of the mechanisms of condensate formation, is providing new insights into human disease and revealing novel therapeutic opportunities. In this Perspective, we propose that such insights could enable a previously unexplored drug discovery approach based on identifying condensate-modifying therapeutics (c-mods), and we discuss the strategies, techniques and challenges involved.
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28
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Villois A, Capasso Palmiero U, Mathur P, Perone G, Schneider T, Li L, Salvalaglio M, deMello A, Stavrakis S, Arosio P. Droplet Microfluidics for the Label-Free Extraction of Complete Phase Diagrams and Kinetics of Liquid-Liquid Phase Separation in Finite Volumes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2202606. [PMID: 36180409 DOI: 10.1002/smll.202202606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/25/2022] [Indexed: 06/16/2023]
Abstract
Liquid-liquid phase separation of polymer and protein solutions is central in many areas of biology and material sciences. Here, an experimental and theoretical framework is provided to investigate the thermodynamics and kinetics of liquid-liquid phase separation in volumes comparable to cells. The strategy leverages droplet microfluidics to accurately measure the volume of the dense phase generated by liquid-liquid phase separation of solutions confined in micro-sized compartments. It is shown that the measurement of the volume fraction of the dense phase at different temperatures allows the evaluation of the binodal lines that determine the coexistence region of the two phases in the temperature-concentration phase diagram. By applying a thermodynamic model of phase separation in finite volumes, it is further shown that the platform can predict and validate kinetic barriers associated with the formation of a dense droplet in a parent dilute phase, therefore connecting thermodynamics and kinetics of liquid-liquid phase separation.
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Affiliation(s)
- Alessia Villois
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Umberto Capasso Palmiero
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Prerit Mathur
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Gaia Perone
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Timo Schneider
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Lunna Li
- Thomas Young Centre and Department of Chemical Engineering, University College London, London, WC1E 7JE, UK
| | - Matteo Salvalaglio
- Thomas Young Centre and Department of Chemical Engineering, University College London, London, WC1E 7JE, UK
| | - Andrew deMello
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Stavros Stavrakis
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
| | - Paolo Arosio
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, 8093, Switzerland
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29
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Alemasova EE, Lavrik OI. A sePARate phase? Poly(ADP-ribose) versus RNA in the organization of biomolecular condensates. Nucleic Acids Res 2022; 50:10817-10838. [PMID: 36243979 DOI: 10.1093/nar/gkac866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 09/14/2022] [Accepted: 10/09/2022] [Indexed: 11/13/2022] Open
Abstract
Condensates are biomolecular assemblies that concentrate biomolecules without the help of membranes. They are morphologically highly versatile and may emerge via distinct mechanisms. Nucleic acids-DNA, RNA and poly(ADP-ribose) (PAR) play special roles in the process of condensate organization. These polymeric scaffolds provide multiple specific and nonspecific interactions during nucleation and 'development' of macromolecular assemblages. In this review, we focus on condensates formed with PAR. We discuss to what extent the literature supports the phase separation origin of these structures. Special attention is paid to similarities and differences between PAR and RNA in the process of dynamic restructuring of condensates during their functioning.
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Affiliation(s)
- Elizaveta E Alemasova
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk 630090, Russia
| | - Olga I Lavrik
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk 630090, Russia.,Novosibirsk State University, Novosibirsk 630090, Russia
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30
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Wang H, Li B, Zuo L, Wang B, Yan Y, Tian K, Zhou R, Wang C, Chen X, Jiang Y, Zheng H, Qin F, Zhang B, Yu Y, Liu CP, Xu Y, Gao J, Qi Z, Deng W, Ji X. The transcriptional coactivator RUVBL2 regulates Pol II clustering with diverse transcription factors. Nat Commun 2022; 13:5703. [PMID: 36171202 PMCID: PMC9519968 DOI: 10.1038/s41467-022-33433-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 09/16/2022] [Indexed: 11/10/2022] Open
Abstract
RNA polymerase II (Pol II) apparatuses are compartmentalized into transcriptional clusters. Whether protein factors control these clusters remains unknown. In this study, we find that the ATPase-associated with diverse cellular activities (AAA + ) ATPase RUVBL2 co-occupies promoters with Pol II and various transcription factors. RUVBL2 interacts with unphosphorylated Pol II in chromatin to promote RPB1 carboxy-terminal domain (CTD) clustering and transcription initiation. Rapid depletion of RUVBL2 leads to a decrease in the number of Pol II clusters and inhibits nascent RNA synthesis, and tethering RUVBL2 to an active promoter enhances Pol II clustering at the promoter. We also identify target genes that are directly linked to the RUVBL2-Pol II axis. Many of these genes are hallmarks of cancers and encode proteins with diverse cellular functions. Our results demonstrate an emerging activity for RUVBL2 in regulating Pol II cluster formation in the nucleus. RNA polymerase II (Pol II) transcription factories play a central role in gene expression and 3D chromatin organization. Here, the authors demonstrate that RUVBL2 directly regulates Pol II clustering at active gene promoters.
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Affiliation(s)
- Hui Wang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.,Department of Pathogenic Biology, Chengdu Medical College, Chengdu, 610500, China
| | - Boyuan Li
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Linyu Zuo
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Bo Wang
- Biomedical Pioneering Innovation Center (BIOPIC), Academy for Advanced Interdisciplinary Studies, Beijing Advanced Innovation Center for Genomics (ICG), Peking-Tsinghua Center for Life Sciences (CLS), School of Life Sciences, Peking University, Beijing, 100871, China
| | - Yan Yan
- Institute for TCM-X; MOE Key Laboratory of Bioinformatics; Bioinformatics Division, BNRist (Beijing National Research Center for Information Science and Technology); Department of Automation, Tsinghua University, Beijing, 100084, China.,Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Kai Tian
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Rong Zhou
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Chenlu Wang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Xizi Chen
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China
| | - Yongpeng Jiang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Haonan Zheng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Fangfei Qin
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Bin Zhang
- Departments of Pathology and Laboratory Medicine, and Pediatrics, University of Rochester Medical Center, 601 Elmwood Ave, Box 608, Rochester, NY, 14642, USA
| | - Yang Yu
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chao-Pei Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yanhui Xu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China
| | - Juntao Gao
- Institute for TCM-X; MOE Key Laboratory of Bioinformatics; Bioinformatics Division, BNRist (Beijing National Research Center for Information Science and Technology); Department of Automation, Tsinghua University, Beijing, 100084, China.,Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China
| | - Zhi Qi
- Center for Quantitative Biology, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Wulan Deng
- Biomedical Pioneering Innovation Center (BIOPIC), Academy for Advanced Interdisciplinary Studies, Beijing Advanced Innovation Center for Genomics (ICG), Peking-Tsinghua Center for Life Sciences (CLS), School of Life Sciences, Peking University, Beijing, 100871, China
| | - Xiong Ji
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
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31
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Gouveia B, Kim Y, Shaevitz JW, Petry S, Stone HA, Brangwynne CP. Capillary forces generated by biomolecular condensates. Nature 2022; 609:255-264. [PMID: 36071192 DOI: 10.1038/s41586-022-05138-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 07/25/2022] [Indexed: 12/21/2022]
Abstract
Liquid-liquid phase separation and related phase transitions have emerged as generic mechanisms in living cells for the formation of membraneless compartments or biomolecular condensates. The surface between two immiscible phases has an interfacial tension, generating capillary forces that can perform work on the surrounding environment. Here we present the physical principles of capillarity, including examples of how capillary forces structure multiphase condensates and remodel biological substrates. As with other mechanisms of intracellular force generation, for example, molecular motors, capillary forces can influence biological processes. Identifying the biomolecular determinants of condensate capillarity represents an exciting frontier, bridging soft matter physics and cell biology.
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Affiliation(s)
- Bernardo Gouveia
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Yoonji Kim
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | | | - Sabine Petry
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA. .,The Howard Hughes Medical Institute, Princeton, NJ, USA.
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32
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Michieletto D, Marenda M. Rheology and Viscoelasticity of Proteins and Nucleic Acids Condensates. JACS AU 2022; 2:1506-1521. [PMID: 35911447 PMCID: PMC9326828 DOI: 10.1021/jacsau.2c00055] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Phase separation is as familiar as watching vinegar separating from oil in vinaigrette. The observation that phase separation of proteins and nucleic acids is widespread in living cells has opened an entire field of research into the biological significance and the biophysical mechanisms of phase separation and protein condensation in biology. Recent evidence indicates that certain proteins and nucleic acids condensates are not simple liquids and instead display both viscous and elastic behaviors, which in turn may have biological significance. The aim of this Perspective is to review the state-of-the-art of this quickly emerging field focusing on the material and rheological properties of protein condensates. Finally, we discuss the different techniques that can be employed to quantify the viscoelasticity of condensates and highlight potential future directions and opportunities for interdisciplinary cross-talk between chemists, physicists, and biologists.
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Affiliation(s)
- Davide Michieletto
- School
of Physics and Astronomy, University of
Edinburgh, Peter Guthrie
Tait Road, Edinburgh EH9
3FD, U.K.
- MRC
Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, U.K.
| | - Mattia Marenda
- School
of Physics and Astronomy, University of
Edinburgh, Peter Guthrie
Tait Road, Edinburgh EH9
3FD, U.K.
- MRC
Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, U.K.
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33
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Kar M, Dar F, Welsh TJ, Vogel LT, Kühnemuth R, Majumdar A, Krainer G, Franzmann TM, Alberti S, Seidel CAM, Knowles TPJ, Hyman AA, Pappu RV. Phase-separating RNA-binding proteins form heterogeneous distributions of clusters in subsaturated solutions. Proc Natl Acad Sci U S A 2022; 119:e2202222119. [PMID: 35787038 DOI: 10.1101/2022.02.03.478969] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
Macromolecular phase separation is thought to be one of the processes that drives the formation of membraneless biomolecular condensates in cells. The dynamics of phase separation are thought to follow the tenets of classical nucleation theory, and, therefore, subsaturated solutions should be devoid of clusters with more than a few molecules. We tested this prediction using in vitro biophysical studies to characterize subsaturated solutions of phase-separating RNA-binding proteins with intrinsically disordered prion-like domains and RNA-binding domains. Surprisingly, and in direct contradiction to expectations from classical nucleation theory, we find that subsaturated solutions are characterized by the presence of heterogeneous distributions of clusters. The distributions of cluster sizes, which are dominated by small species, shift continuously toward larger sizes as protein concentrations increase and approach the saturation concentration. As a result, many of the clusters encompass tens to hundreds of molecules, while less than 1% of the solutions are mesoscale species that are several hundred nanometers in diameter. We find that cluster formation in subsaturated solutions and phase separation in supersaturated solutions are strongly coupled via sequence-encoded interactions. We also find that cluster formation and phase separation can be decoupled using solutes as well as specific sets of mutations. Our findings, which are concordant with predictions for associative polymers, implicate an interplay between networks of sequence-specific and solubility-determining interactions that, respectively, govern cluster formation in subsaturated solutions and the saturation concentrations above which phase separation occurs.
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Affiliation(s)
- Mrityunjoy Kar
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
| | - Furqan Dar
- Department of Physics, Washington University in St. Louis, St. Louis, MO 63130
| | - Timothy J Welsh
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Laura T Vogel
- Department of Molecular Physical Chemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Ralf Kühnemuth
- Department of Molecular Physical Chemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Anupa Majumdar
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
| | - Georg Krainer
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Titus M Franzmann
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, 01069 Dresden, Germany
| | - Simon Alberti
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, 01069 Dresden, Germany
| | - Claus A M Seidel
- Department of Molecular Physical Chemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
- Cavendish Laboratory, University of Cambridge, CB3 0HE Cambridge, United Kingdom
| | - Anthony A Hyman
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
| | - Rohit V Pappu
- Department of Biomedical Engineering, Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130
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34
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Kar M, Dar F, Welsh TJ, Vogel LT, Kühnemuth R, Majumdar A, Krainer G, Franzmann TM, Alberti S, Seidel CAM, Knowles TPJ, Hyman AA, Pappu RV. Phase-separating RNA-binding proteins form heterogeneous distributions of clusters in subsaturated solutions. Proc Natl Acad Sci U S A 2022; 119:e2202222119. [PMID: 35787038 PMCID: PMC9282234 DOI: 10.1073/pnas.2202222119] [Citation(s) in RCA: 99] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 05/26/2022] [Indexed: 12/14/2022] Open
Abstract
Macromolecular phase separation is thought to be one of the processes that drives the formation of membraneless biomolecular condensates in cells. The dynamics of phase separation are thought to follow the tenets of classical nucleation theory, and, therefore, subsaturated solutions should be devoid of clusters with more than a few molecules. We tested this prediction using in vitro biophysical studies to characterize subsaturated solutions of phase-separating RNA-binding proteins with intrinsically disordered prion-like domains and RNA-binding domains. Surprisingly, and in direct contradiction to expectations from classical nucleation theory, we find that subsaturated solutions are characterized by the presence of heterogeneous distributions of clusters. The distributions of cluster sizes, which are dominated by small species, shift continuously toward larger sizes as protein concentrations increase and approach the saturation concentration. As a result, many of the clusters encompass tens to hundreds of molecules, while less than 1% of the solutions are mesoscale species that are several hundred nanometers in diameter. We find that cluster formation in subsaturated solutions and phase separation in supersaturated solutions are strongly coupled via sequence-encoded interactions. We also find that cluster formation and phase separation can be decoupled using solutes as well as specific sets of mutations. Our findings, which are concordant with predictions for associative polymers, implicate an interplay between networks of sequence-specific and solubility-determining interactions that, respectively, govern cluster formation in subsaturated solutions and the saturation concentrations above which phase separation occurs.
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Affiliation(s)
- Mrityunjoy Kar
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
| | - Furqan Dar
- Department of Physics, Washington University in St. Louis, St. Louis, MO 63130
| | - Timothy J. Welsh
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Laura T. Vogel
- Department of Molecular Physical Chemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Ralf Kühnemuth
- Department of Molecular Physical Chemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Anupa Majumdar
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
| | - Georg Krainer
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
| | - Titus M. Franzmann
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, 01069 Dresden, Germany
| | - Simon Alberti
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, 01069 Dresden, Germany
| | - Claus A. M. Seidel
- Department of Molecular Physical Chemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Tuomas P. J. Knowles
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, CB2 1EW Cambridge, United Kingdom
- Cavendish Laboratory, University of Cambridge, CB3 0HE Cambridge, United Kingdom
| | - Anthony A. Hyman
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
| | - Rohit V. Pappu
- Department of Biomedical Engineering, Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130
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35
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Lee DSW, Strom AR, Brangwynne CP. The mechanobiology of nuclear phase separation. APL Bioeng 2022; 6:021503. [PMID: 35540725 PMCID: PMC9054271 DOI: 10.1063/5.0083286] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/19/2022] [Indexed: 02/06/2023] Open
Abstract
The cell nucleus can be thought of as a complex, dynamic, living material, which functions to organize and protect the genome and coordinate gene expression. These functions are achieved via intricate mechanical and biochemical interactions among its myriad components, including the nuclear lamina, nuclear bodies, and the chromatin itself. While the biophysical organization of the nuclear lamina and chromatin have been thoroughly studied, the concept that liquid-liquid phase separation and related phase transitions play a role in establishing nuclear structure has emerged only recently. Phase transitions are likely to be intimately coupled to the mechanobiology of structural elements in the nucleus, but their interplay with one another is still not understood. Here, we review recent developments on the role of phase separation and mechanics in nuclear organization and discuss the functional implications in cell physiology and disease states.
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Affiliation(s)
- Daniel S. W. Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
| | - Amy R. Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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36
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do Amaral MJ, Freire MHO, Almeida MS, Pinheiro AS, Cordeiro Y. Phase separation of the mammalian prion protein: physiological and pathological perspectives. J Neurochem 2022. [PMID: 35149997 DOI: 10.1111/jnc.15586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/24/2022] [Accepted: 01/31/2022] [Indexed: 11/27/2022]
Abstract
Abnormal phase transitions have been implicated in the occurrence of proteinopathies. Disordered proteins with nucleic acid binding ability drive the formation of reversible micron-sized condensates capable of controlling nucleic acid processing/transport. This mechanism, achieved via liquid-liquid phase separation (LLPS), underlies the formation of long-studied membraneless organelles (e.g., nucleolus) and various transient condensates formed by driver proteins. The prion protein (PrP) is not a classical nucleic acid-binding protein. However, it binds nucleic acids with high affinity, undergoes nucleocytoplasmic shuttling, contains a long intrinsically disordered region rich in glycines and evenly spaced aromatic residues, among other biochemical/biophysical properties of bona fide drivers of phase transitions. Because of this, our group and others have characterized LLPS of recombinant PrP. In vitro phase separation of PrP is modulated by nucleic acid aptamers, and, depending on the aptamer conformation, the liquid droplets evolve to solid-like species. Herein we discuss recent studies and previous evidence supporting PrP phase transitions. We focus on the central role of LLPS related to PrP physiology and pathology, with a special emphasis on the interaction of PrP with different ligands, such as proteins and nucleic acids, which can play a role in prion disease pathogenesis. Finally, we comment on therapeutic strategies directed at the nonfunctional phase separation that could potentially tackle prion diseases or other protein misfolding disorders.
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Affiliation(s)
- Mariana J do Amaral
- Faculty of Pharmacy, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | | | | | - Anderson S Pinheiro
- Department of Biochemistry, Institute of Chemistry, Rio de Janeiro, RJ, Brazil
| | - Yraima Cordeiro
- Faculty of Pharmacy, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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37
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Transcriptional Regulation and Implications for Controlling Hox Gene Expression. J Dev Biol 2022; 10:jdb10010004. [PMID: 35076545 PMCID: PMC8788451 DOI: 10.3390/jdb10010004] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/04/2022] [Accepted: 01/06/2022] [Indexed: 02/06/2023] Open
Abstract
Hox genes play key roles in axial patterning and regulating the regional identity of cells and tissues in a wide variety of animals from invertebrates to vertebrates. Nested domains of Hox expression generate a combinatorial code that provides a molecular framework for specifying the properties of tissues along the A–P axis. Hence, it is important to understand the regulatory mechanisms that coordinately control the precise patterns of the transcription of clustered Hox genes required for their roles in development. New insights are emerging about the dynamics and molecular mechanisms governing transcriptional regulation, and there is interest in understanding how these may play a role in contributing to the regulation of the expression of the clustered Hox genes. In this review, we summarize some of the recent findings, ideas and emerging mechanisms underlying the regulation of transcription in general and consider how they may be relevant to understanding the transcriptional regulation of Hox genes.
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38
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Lee R, Kang MK, Kim YJ, Yang B, Shim H, Kim S, Kim K, Yang CM, Min BG, Jung WJ, Lee EC, Joo JS, Park G, Cho WK, Kim HP. CTCF-mediated chromatin looping provides a topological framework for the formation of phase-separated transcriptional condensates. Nucleic Acids Res 2021; 50:207-226. [PMID: 34931241 PMCID: PMC8855298 DOI: 10.1093/nar/gkab1242] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/22/2021] [Accepted: 12/03/2021] [Indexed: 12/31/2022] Open
Abstract
CTCF is crucial to the organization of mammalian genomes into loop structures. According to recent studies, the transcription apparatus is compartmentalized and concentrated at super-enhancers to form phase-separated condensates and drive the expression of cell-identity genes. However, it remains unclear whether and how transcriptional condensates are coupled to higher-order chromatin organization. Here, we show that CTCF is essential for RNA polymerase II (Pol II)-mediated chromatin interactions, which occur as hyperconnected spatial clusters at super-enhancers. We also demonstrate that CTCF clustering, unlike Pol II clustering, is independent of liquid-liquid phase-separation and resistant to perturbation of transcription. Interestingly, clusters of Pol II, BRD4, and MED1 were found to dissolve upon CTCF depletion, but were reinstated upon restoration of CTCF, suggesting a potent instructive function for CTCF in the formation of transcriptional condensates. Overall, we provide evidence suggesting that CTCF-mediated chromatin looping acts as an architectural prerequisite for the assembly of phase-separated transcriptional condensates.
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Affiliation(s)
- Ryanggeun Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea.,College of Natural Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Moo-Koo Kang
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Yong-Jin Kim
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Bobae Yang
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Hwanyong Shim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Sugyung Kim
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Kyungwoo Kim
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Chul Min Yang
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Byeong-Gyu Min
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Woong-Jae Jung
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Eun-Chong Lee
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Jung-Sik Joo
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
| | - Gunhee Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Won-Ki Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea.,KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Hyoung-Pyo Kim
- Department of Environmental Medical Biology, Institute of Tropical Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.,Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.,Yonsei Genome Center, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea
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39
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Sawner AS, Ray S, Yadav P, Mukherjee S, Panigrahi R, Poudyal M, Patel K, Ghosh D, Kummerant E, Kumar A, Riek R, Maji SK. Modulating α-Synuclein Liquid-Liquid Phase Separation. Biochemistry 2021; 60:3676-3696. [PMID: 34431665 DOI: 10.1021/acs.biochem.1c00434] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Liquid-liquid phase separation (LLPS) is a crucial phenomenon for the formation of functional membraneless organelles. However, LLPS is also responsible for protein aggregation in various neurodegenerative diseases such as amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease (PD). Recently, several reports, including ours, have shown that α-synuclein (α-Syn) undergoes LLPS and a subsequent liquid-to-solid phase transition, which leads to amyloid fibril formation. However, how the environmental (and experimental) parameters modulate the α-Syn LLPS remains elusive. Here, we show that in vitro α-Syn LLPS is strongly dependent on the presence of salts, which allows charge neutralization at both terminal segments of protein and therefore promotes hydrophobic interactions supportive for LLPS. Using various purification methods and experimental conditions, we showed, depending upon conditions, α-Syn undergoes either spontaneous (instantaneous) or delayed LLPS. Furthermore, we delineate that the kinetics of liquid droplet formation (i.e., the critical concentration and critical time) is relative and can be modulated by the salt/counterion concentration, pH, presence of surface, PD-associated multivalent cations, and N-terminal acetylation, which are all known to regulate α-Syn aggregation in vitro. Together, our observations suggest that α-Syn LLPS and subsequent liquid-to-solid phase transition could be pathological, which can be triggered only under disease-associated conditions (high critical concentration and/or conditions promoting α-Syn self-assembly). This study will significantly improve our understanding of the molecular mechanisms of α-Syn LLPS and the liquid-to-solid transition.
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Affiliation(s)
- Ajay Singh Sawner
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Soumik Ray
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Preeti Yadav
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Semanti Mukherjee
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Rajlaxmi Panigrahi
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Manisha Poudyal
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Komal Patel
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Dhiman Ghosh
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Eric Kummerant
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Roland Riek
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Samir K Maji
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
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40
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Tom JK, Deniz AA. Complex dynamics of multicomponent biological coacervates. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2021.101488] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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41
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Jin X, Lee JE, Schaefer C, Luo X, Wollman AJM, Payne-Dwyer AL, Tian T, Zhang X, Chen X, Li Y, McLeish TCB, Leake MC, Bai F. Membraneless organelles formed by liquid-liquid phase separation increase bacterial fitness. SCIENCE ADVANCES 2021; 7:eabh2929. [PMID: 34669478 PMCID: PMC8528417 DOI: 10.1126/sciadv.abh2929] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 08/27/2021] [Indexed: 05/20/2023]
Abstract
Liquid-liquid phase separation is emerging as a crucial phenomenon in several fundamental cell processes. A range of eukaryotic systems exhibit liquid condensates. However, their function in bacteria, which, in general, lack membrane-bound compartments, remains less clear. Here, we used high-resolution optical microscopy to observe single bacterial aggresomes, nanostructured intracellular assemblies of proteins, to undercover their role in cell stress. We find that proteins inside aggresomes are mobile and undergo dynamic turnover, consistent with a liquid state. Our observations are in quantitative agreement with phase-separated liquid droplet formation driven by interacting proteins under thermal equilibrium that nucleate following diffusive collisions in the cytoplasm. We have found aggresomes in multiple species of bacteria and show that these emergent, metastable liquid-structured protein assemblies increase bacterial fitness by enabling cells to tolerate environmental stresses.
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Affiliation(s)
- Xin Jin
- Biomedical Pioneering Innovation Centre (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | - Ji-Eun Lee
- Department of Physics, University of York, York, UK
| | | | - Xinwei Luo
- Biomedical Pioneering Innovation Centre (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | | | - Alex L. Payne-Dwyer
- Department of Physics, University of York, York, UK
- Department of Biology, University of York, York, UK
| | - Tian Tian
- Biomedical Pioneering Innovation Centre (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | - Xiaowei Zhang
- Biomedical Pioneering Innovation Centre (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | - Xiao Chen
- Biomedical Pioneering Innovation Centre (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | - Yingxing Li
- Biomedical Pioneering Innovation Centre (BIOPIC), School of Life Sciences, Peking University, Beijing, China
- Department of Medical Research Center, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | | | - Mark C. Leake
- Department of Physics, University of York, York, UK
- Department of Biology, University of York, York, UK
- Corresponding author. (F.B.); (M.C.L.)
| | - Fan Bai
- Biomedical Pioneering Innovation Centre (BIOPIC), School of Life Sciences, Peking University, Beijing, China
- Beijing Advanced Innovation Center for Genomics (ICG), Peking University, Beijing, China
- Corresponding author. (F.B.); (M.C.L.)
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42
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Fassler JS, Skuodas S, Weeks DL, Phillips BT. Protein Aggregation and Disaggregation in Cells and Development. J Mol Biol 2021; 433:167215. [PMID: 34450138 PMCID: PMC8530975 DOI: 10.1016/j.jmb.2021.167215] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 08/01/2021] [Accepted: 08/18/2021] [Indexed: 12/12/2022]
Abstract
Protein aggregation is a feature of numerous neurodegenerative diseases. However, regulated, often reversible, formation of protein aggregates, also known as condensates, helps control a wide range of cellular activities including stress response, gene expression, memory, cell development and differentiation. This review presents examples of aggregates found in biological systems, how they are used, and cellular strategies that control aggregation and disaggregation. We include features of the aggregating proteins themselves, environmental factors, co-aggregates, post-translational modifications and well-known aggregation-directed activities that influence their formation, material state, stability and dissolution. We highlight the emerging roles of biomolecular condensates in early animal development, and disaggregation processing proteins that have recently been shown to play key roles in gametogenesis and embryogenesis.
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Affiliation(s)
- Jan S Fassler
- Department of Biology, University of Iowa, Iowa City, IA 52242, United States.
| | - Sydney Skuodas
- Department of Biology, University of Iowa, Iowa City, IA 52242, United States. https://twitter.com/@sskuodas
| | - Daniel L Weeks
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Bryan T Phillips
- Department of Biology, University of Iowa, Iowa City, IA 52242, United States. https://twitter.com/@bt4phillips
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43
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Fritsch AW, Diaz-Delgadillo AF, Adame-Arana O, Hoege C, Mittasch M, Kreysing M, Leaver M, Hyman AA, Jülicher F, Weber CA. Local thermodynamics govern formation and dissolution of Caenorhabditis elegans P granule condensates. Proc Natl Acad Sci U S A 2021; 118:e2102772118. [PMID: 34507991 PMCID: PMC8449359 DOI: 10.1073/pnas.2102772118] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2021] [Indexed: 12/31/2022] Open
Abstract
Membraneless compartments, also known as condensates, provide chemically distinct environments and thus spatially organize the cell. A well-studied example of condensates is P granules in the roundworm Caenorhabditis elegans that play an important role in the development of the germline. P granules are RNA-rich protein condensates that share the key properties of liquid droplets such as a spherical shape, the ability to fuse, and fast diffusion of their molecular components. An outstanding question is to what extent phase separation at thermodynamic equilibrium is appropriate to describe the formation of condensates in an active cellular environment. To address this question, we investigate the response of P granule condensates in living cells to temperature changes. We observe that P granules dissolve upon increasing the temperature and recondense upon lowering the temperature in a reversible manner. Strikingly, this temperature response can be captured by in vivo phase diagrams that are well described by a Flory-Huggins model at thermodynamic equilibrium. This finding is surprising due to active processes in a living cell. To address the impact of such active processes on intracellular phase separation, we discuss temperature heterogeneities. We show that, for typical estimates of the density of active processes, temperature represents a well-defined variable and that mesoscopic volume elements are at local thermodynamic equilibrium. Our findings provide strong evidence that P granule assembly and disassembly are governed by phase separation based on local thermal equilibria where the nonequilibrium nature of the cytoplasm is manifested on larger scales.
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Affiliation(s)
- Anatol W Fritsch
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | | | - Omar Adame-Arana
- Division Biological Physics, Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Carsten Hoege
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Matthäus Mittasch
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Dewpoint Therapeutics GmbH, 01307 Dresden, Germany
| | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Mark Leaver
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01307 Dresden, Germany
| | - Frank Jülicher
- Division Biological Physics, Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01307 Dresden, Germany
| | - Christoph A Weber
- Division Biological Physics, Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany;
- Center for Systems Biology Dresden, 01307 Dresden, Germany
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44
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Pancholi A, Klingberg T, Zhang W, Prizak R, Mamontova I, Noa A, Sobucki M, Kobitski AY, Nienhaus GU, Zaburdaev V, Hilbert L. RNA polymerase II clusters form in line with surface condensation on regulatory chromatin. Mol Syst Biol 2021; 17:e10272. [PMID: 34569155 PMCID: PMC8474054 DOI: 10.15252/msb.202110272] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 08/26/2021] [Accepted: 09/10/2021] [Indexed: 12/15/2022] Open
Abstract
It is essential for cells to control which genes are transcribed into RNA. In eukaryotes, two major control points are recruitment of RNA polymerase II (Pol II) into a paused state, and subsequent pause release toward transcription. Pol II recruitment and pause release occur in association with macromolecular clusters, which were proposed to be formed by a liquid-liquid phase separation mechanism. How such a phase separation mechanism relates to the interaction of Pol II with DNA during recruitment and transcription, however, remains poorly understood. Here, we use live and super-resolution microscopy in zebrafish embryos to reveal Pol II clusters with a large variety of shapes, which can be explained by a theoretical model in which regulatory chromatin regions provide surfaces for liquid-phase condensation at concentrations that are too low for canonical liquid-liquid phase separation. Model simulations and chemical perturbation experiments indicate that recruited Pol II contributes to the formation of these surface-associated condensates, whereas elongating Pol II is excluded from these condensates and thereby drives their unfolding.
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Affiliation(s)
- Agnieszka Pancholi
- Zoological InstituteDepartment of Systems Biology and BioinformaticsKarlsruhe Institute of TechnologyKarlsruheGermany
- Institute of Biological and Chemical Systems—Biological Information ProcessingKarlsruhe Institute of TechnologyEggenstein‐LeopoldshafenGermany
| | - Tim Klingberg
- Department of BiologyFriedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
- Max‐Planck‐Zentrum für Physik und MedizinErlangenGermany
| | - Weichun Zhang
- Institute of Applied PhysicsKarlsruhe Institute of TechnologyKarlsruheGermany
- Institute of NanotechnologyKarlsruhe Institute of TechnologyEggenstein‐LeopoldshafenGermany
| | - Roshan Prizak
- Institute of Biological and Chemical Systems—Biological Information ProcessingKarlsruhe Institute of TechnologyEggenstein‐LeopoldshafenGermany
| | - Irina Mamontova
- Institute of Biological and Chemical Systems—Biological Information ProcessingKarlsruhe Institute of TechnologyEggenstein‐LeopoldshafenGermany
| | - Amra Noa
- Institute of Biological and Chemical Systems—Biological Information ProcessingKarlsruhe Institute of TechnologyEggenstein‐LeopoldshafenGermany
| | - Marcel Sobucki
- Institute of Biological and Chemical Systems—Biological Information ProcessingKarlsruhe Institute of TechnologyEggenstein‐LeopoldshafenGermany
| | - Andrei Yu Kobitski
- Institute of Applied PhysicsKarlsruhe Institute of TechnologyKarlsruheGermany
| | - Gerd Ulrich Nienhaus
- Institute of Biological and Chemical Systems—Biological Information ProcessingKarlsruhe Institute of TechnologyEggenstein‐LeopoldshafenGermany
- Institute of Applied PhysicsKarlsruhe Institute of TechnologyKarlsruheGermany
- Institute of NanotechnologyKarlsruhe Institute of TechnologyEggenstein‐LeopoldshafenGermany
- Department of PhysicsUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
| | - Vasily Zaburdaev
- Department of BiologyFriedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
- Max‐Planck‐Zentrum für Physik und MedizinErlangenGermany
| | - Lennart Hilbert
- Zoological InstituteDepartment of Systems Biology and BioinformaticsKarlsruhe Institute of TechnologyKarlsruheGermany
- Institute of Biological and Chemical Systems—Biological Information ProcessingKarlsruhe Institute of TechnologyEggenstein‐LeopoldshafenGermany
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45
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The multiscale and multiphase organization of the transcriptome. Emerg Top Life Sci 2021; 4:265-280. [PMID: 32542380 DOI: 10.1042/etls20190187] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/08/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023]
Abstract
Gene expression must be co-ordinated to cellular activity. From transcription to decay, the expression of millions of RNA molecules is highly synchronized. RNAs are covered by proteins that regulate every aspect of their cellular life: expression, storage, translational status, localization, and decay. Many RNAs and their associated regulatory proteins can coassemble to condense into liquid droplets, viscoelastic hydrogels, freeze into disorganized glass-like aggregates, or harden into quasi-crystalline solids. Phase separations provide a framework for transcriptome organization where the single functional unit is no longer a transcript but instead an RNA regulon. Here, we will analyze the interaction networks that underlie RNA super-assemblies, assess the complex multiscale, multiphase architecture of the transcriptome, and explore how the biophysical state of an RNA molecule can define its fate. Phase separations are emerging as critical routes for the epitranscriptomic control of gene expression.
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46
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Intrinsic disorder and phase transitions: Pieces in the puzzling role of the prion protein in health and disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 183:1-43. [PMID: 34656326 DOI: 10.1016/bs.pmbts.2021.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
After four decades of prion protein research, the pressing questions in the literature remain similar to the common existential dilemmas. Who am I? Some structural characteristics of the cellular prion protein (PrPC) and scrapie PrP (PrPSc) remain unknown: there are no high-resolution atomic structures for either full-length endogenous human PrPC or isolated infectious PrPSc particles. Why am I here? It is not known why PrPC and PrPSc are found in specific cellular compartments such as the nucleus; while the physiological functions of PrPC are still being uncovered, the misfolding site remains obscure. Where am I going? The subcellular distribution of PrPC and PrPSc is wide (reported in 10 different locations in the cell). This complexity is further exacerbated by the eight different PrP fragments yielded from conserved proteolytic cleavages and by reversible post-translational modifications, such as glycosylation, phosphorylation, and ubiquitination. Moreover, about 55 pathological mutations and 16 polymorphisms on the PrP gene (PRNP) have been described. Prion diseases also share unique, challenging features: strain phenomenon (associated with the heterogeneity of PrPSc conformations) and the possible transmissibility between species, factors which contribute to PrP undruggability. However, two recent concepts in biochemistry-intrinsically disordered proteins and phase transitions-may shed light on the molecular basis of PrP's role in physiology and disease.
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47
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Klenerman D, Sanchez SE, Whiten DR, Meisl G, Ruggeri FS, Hidari E. Alpha synuclein only forms fibrils in vitro when larger than its critical size of 70 monomers. Chembiochem 2021; 22:2867-2871. [PMID: 34383993 PMCID: PMC8518629 DOI: 10.1002/cbic.202100285] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/10/2021] [Indexed: 12/03/2022]
Abstract
The aggregation of α‐synuclein into small soluble aggregates and then fibrils is important in the development and spreading of aggregates through the brain in Parkinson's disease. Fibrillar aggregates can grow by monomer addition and then break into fragments that could spread into neighboring cells. The rate constants for fibril elongation and fragmentation have been measured but it is not known how large an aggregate needs to be before fibril formation is thermodynamically favorable. This critical size is an important parameter controlling at what stage in an aggregation reaction fibrils can form and replicate. We determined this value to be approximately 70 monomers using super‐resolution and atomic force microscopy imaging of individual α‐synuclein aggregates formed in solution over long time periods. This represents the minimum size for a stable α‐synuclein fibril and we hypothesis the formation of aggregates of this size in a cell represents a tipping point at which rapid replication occurs.
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Affiliation(s)
- David Klenerman
- University of Cambridge, Department of Chemistry, Lensfield Road, CB2 1EW, Cambridge, UNITED KINGDOM
| | | | - Daniel R Whiten
- Kolling Institute of Medical Research, Kolling Institute, AUSTRALIA
| | - Georg Meisl
- University of Cambridge, Chemistry, UNITED KINGDOM
| | - Francesco Simone Ruggeri
- Wageningen UR PRI: Wageningen University and Research Wageningen Plant Research, organic and physical chemistry Laboratories, NETHERLANDS
| | - Eric Hidari
- University of Cambridge, Chemistry, UNITED KINGDOM
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48
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Martin EW, Harmon TS, Hopkins JB, Chakravarthy S, Incicco JJ, Schuck P, Soranno A, Mittag T. A multi-step nucleation process determines the kinetics of prion-like domain phase separation. Nat Commun 2021; 12:4513. [PMID: 34301955 PMCID: PMC8302766 DOI: 10.1038/s41467-021-24727-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 06/30/2021] [Indexed: 11/08/2022] Open
Abstract
Compartmentalization by liquid-liquid phase separation (LLPS) has emerged as a ubiquitous mechanism underlying the organization of biomolecules in space and time. Here, we combine rapid-mixing time-resolved small-angle X-ray scattering (SAXS) approaches to characterize the assembly kinetics of a prototypical prion-like domain with equilibrium techniques that characterize its phase boundaries and the size distribution of clusters prior to phase separation. We find two kinetic regimes on the micro- to millisecond timescale that are distinguished by the size distribution of clusters. At the nanoscale, small complexes are formed with low affinity. After initial unfavorable complex assembly, additional monomers are added with higher affinity. At the mesoscale, assembly resembles classical homogeneous nucleation. Careful multi-pronged characterization is required for the understanding of condensate assembly mechanisms and will promote understanding of how the kinetics of biological phase separation is encoded in biomolecules.
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Affiliation(s)
- Erik W Martin
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - Tyler S Harmon
- The Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Jesse B Hopkins
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL, USA
| | - J Jeremías Incicco
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO, USA
- Center for Science and Engineering of Living Cells (CSELS), Washington University in St. Louis, St. Louis, MO, USA
| | - Peter Schuck
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Andrea Soranno
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO, USA
- Center for Science and Engineering of Living Cells (CSELS), Washington University in St. Louis, St. Louis, MO, USA
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.
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Portz B, Lee BL, Shorter J. FUS and TDP-43 Phases in Health and Disease. Trends Biochem Sci 2021; 46:550-563. [PMID: 33446423 PMCID: PMC8195841 DOI: 10.1016/j.tibs.2020.12.005] [Citation(s) in RCA: 128] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 11/24/2020] [Accepted: 12/08/2020] [Indexed: 12/14/2022]
Abstract
The distinct prion-like domains (PrLDs) of FUS and TDP-43, modulate phase transitions that result in condensates with a range of material states. These assemblies are implicated in both health and disease. In this review, we examine how sequence, structure, post-translational modifications, and RNA can affect the self-assembly of these RNA-binding proteins (RBPs). We discuss how our emerging understanding of FUS and TDP-43 liquid-liquid phase separation (LLPS) and aggregation, could be leveraged to design new therapies for neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and limbic-predominant age-related TDP-43 encephalopathy (LATE).
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Affiliation(s)
- Bede Portz
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bo Lim Lee
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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50
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Posey AE, Ruff KM, Lalmansingh JM, Kandola TS, Lange JJ, Halfmann R, Pappu RV. Mechanistic Inferences From Analysis of Measurements of Protein Phase Transitions in Live Cells. J Mol Biol 2021; 433:166848. [PMID: 33539877 PMCID: PMC8561728 DOI: 10.1016/j.jmb.2021.166848] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/10/2021] [Accepted: 01/25/2021] [Indexed: 02/07/2023]
Abstract
The combination of phase separation and disorder-to-order transitions can give rise to ordered, semi-crystalline fibrillar assemblies that underlie prion phenomena namely, the non-Mendelian transfer of information across cells. Recently, a method known as Distributed Amphifluoric Förster Resonance Energy Transfer (DAmFRET) was developed to study the convolution of phase separation and disorder-to-order transitions in live cells. In this assay, a protein of interest is expressed to a broad range of concentrations and the acquisition of local density and order, measured by changes in FRET, is used to map phase transitions for different proteins. The high-throughput nature of this assay affords the promise of uncovering sequence-to-phase behavior relationships in live cells. Here, we report the development of a supervised method to obtain automated and accurate classifications of phase transitions quantified using the DAmFRET assay. Systems that we classify as undergoing two-state discontinuous transitions are consistent with prion-like behaviors, although the converse is not always true. We uncover well-established and surprising new sequence features that contribute to two-state phase behavior of prion-like domains. Additionally, our method enables quantitative, comparative assessments of sequence-specific driving forces for phase transitions in live cells. Finally, we demonstrate that a modest augmentation of DAmFRET measurements, specifically time-dependent protein expression profiles, can allow one to apply classical nucleation theory to extract sequence-specific lower bounds on the probability of nucleating ordered assemblies. Taken together, our approaches lead to a useful analysis pipeline that enables the extraction of mechanistic inferences regarding phase transitions in live cells.
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Affiliation(s)
- Ammon E Posey
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA.
| | - Kiersten M Ruff
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Jared M Lalmansingh
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Physics, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Tejbir S Kandola
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA; The Open University, Milton Keynes MK7 6AA, United Kingdom
| | - Jeffrey J Lange
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Randal Halfmann
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA.
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