1
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Kubitscheck U, Siebrasse JP. Pre-ribosomal particles from nucleoli to cytoplasm. Nucleus 2024; 15:2373052. [PMID: 38940456 PMCID: PMC11216097 DOI: 10.1080/19491034.2024.2373052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 06/21/2024] [Indexed: 06/29/2024] Open
Abstract
The analysis of nucleocytoplasmic transport of proteins and messenger RNA has been the focus of advanced microscopic approaches. Recently, it has been possible to identify and visualize individual pre-ribosomal particles on their way through the nuclear pore complex using both electron and light microscopy. In this review, we focused on the transport of pre-ribosomal particles in the nucleus on their way to and through the pores.
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Affiliation(s)
- Ulrich Kubitscheck
- Clausius Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
| | - Jan Peter Siebrasse
- Clausius Institute of Physical and Theoretical Chemistry, University of Bonn, Bonn, Germany
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2
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Fare CM, Rothstein JD. Nuclear pore dysfunction and disease: a complex opportunity. Nucleus 2024; 15:2314297. [PMID: 38383349 PMCID: PMC10883112 DOI: 10.1080/19491034.2024.2314297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/30/2024] [Indexed: 02/23/2024] Open
Abstract
The separation of genetic material from bulk cytoplasm has enabled the evolution of increasingly complex organisms, allowing for the development of sophisticated forms of life. However, this complexity has created new categories of dysfunction, including those related to the movement of material between cellular compartments. In eukaryotic cells, nucleocytoplasmic trafficking is a fundamental biological process, and cumulative disruptions to nuclear integrity and nucleocytoplasmic transport are detrimental to cell survival. This is particularly true in post-mitotic neurons, where nuclear pore injury and errors to nucleocytoplasmic trafficking are strongly associated with neurodegenerative disease. In this review, we summarize the current understanding of nuclear pore biology in physiological and pathological contexts and discuss potential therapeutic approaches for addressing nuclear pore injury and dysfunctional nucleocytoplasmic transport.
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Affiliation(s)
- Charlotte M Fare
- Department of Neurology and Brain Science Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Jeffrey D Rothstein
- Department of Neurology and Brain Science Institute, Johns Hopkins University, Baltimore, MD, USA
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3
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Matsuda A, Mansour A, Mofrad MRK. Deciphering the intrinsically disordered characteristics of the FG-Nups through the lens of polymer physics. Nucleus 2024; 15:2399247. [PMID: 39282864 PMCID: PMC11407397 DOI: 10.1080/19491034.2024.2399247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024] Open
Abstract
The nuclear pore complex (NPC) is a critical gateway regulating molecular transport between the nucleus and cytoplasm. It allows small molecules to pass freely, while larger molecules require nuclear transport receptors to traverse the barrier. This selective permeability is maintained by phenylalanine-glycine-rich nucleoporins (FG-Nups), intrinsically disordered proteins that fill the NPC's central channel. The disordered and flexible nature of FG-Nups complicates their spatial characterization with conventional structural biology techniques. To address this challenge, polymer physics offers a valuable framework for describing FG-Nup behavior, reducing their complex structures to a few key parameters. In this review, we explore how polymer physics models FG-Nups using these parameters and discuss experimental efforts to quantify them in various contexts, providing insights into the conformational properties of FG-Nups.
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Affiliation(s)
- Atsushi Matsuda
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA
| | - Abdullah Mansour
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA
- Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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4
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Mallik S, Poch D, Burick S, Schlieker C. Protein folding and quality control during nuclear transport. Curr Opin Cell Biol 2024; 90:102407. [PMID: 39142062 DOI: 10.1016/j.ceb.2024.102407] [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: 05/24/2024] [Revised: 07/06/2024] [Accepted: 07/16/2024] [Indexed: 08/16/2024]
Abstract
The spatial separation of protein synthesis from the compartmental destiny of proteins led to the evolution of transport systems that are efficient and yet highly specific. Co-translational transport has emerged as a strategy to avoid cytosolic aggregation of folding intermediates and the need for energy-consuming unfolding strategies to enable transport through narrow conduits connecting compartments. While translation and compartmental translocation are at times tightly coordinated, we know very little about the temporal coordination of translation, protein folding, and nuclear import. Here, we consider the implications of co-translational engagement of nuclear import machinery. We propose that the dynamic interplay of karyopherins and intrinsically disordered nucleoporins create a favorable protein folding environment for cargo en route to the nuclear compartment while maintaining a barrier function of the nuclear pore complex. Our model is discussed in the context of neurological disorders that are tied to defects in nuclear transport and protein quality control.
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Affiliation(s)
- Sunanda Mallik
- Yale University, Department of Molecular Biophysics and Biochemistry, New Haven, CT, USA
| | - Dylan Poch
- Yale University, Department of Molecular Biophysics and Biochemistry, New Haven, CT, USA
| | - Sophia Burick
- Yale University, Department of Molecular Biophysics and Biochemistry, New Haven, CT, USA
| | - Christian Schlieker
- Yale University, Department of Molecular Biophysics and Biochemistry, New Haven, CT, USA; Yale School of Medicine, Department of Cell Biology, New Haven, CT, USA.
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5
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Jann C, Giofré S, Bhattacharjee R, Lemke EA. Cracking the Code: Reprogramming the Genetic Script in Prokaryotes and Eukaryotes to Harness the Power of Noncanonical Amino Acids. Chem Rev 2024; 124:10281-10362. [PMID: 39120726 DOI: 10.1021/acs.chemrev.3c00878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
Over 500 natural and synthetic amino acids have been genetically encoded in the last two decades. Incorporating these noncanonical amino acids into proteins enables many powerful applications, ranging from basic research to biotechnology, materials science, and medicine. However, major challenges remain to unleash the full potential of genetic code expansion across disciplines. Here, we provide an overview of diverse genetic code expansion methodologies and systems and their final applications in prokaryotes and eukaryotes, represented by Escherichia coli and mammalian cells as the main workhorse model systems. We highlight the power of how new technologies can be first established in simple and then transferred to more complex systems. For example, whole-genome engineering provides an excellent platform in bacteria for enabling transcript-specific genetic code expansion without off-targets in the transcriptome. In contrast, the complexity of a eukaryotic cell poses challenges that require entirely new approaches, such as striving toward establishing novel base pairs or generating orthogonally translating organelles within living cells. We connect the milestones in expanding the genetic code of living cells for encoding novel chemical functionalities to the most recent scientific discoveries, from optimizing the physicochemical properties of noncanonical amino acids to the technological advancements for their in vivo incorporation. This journey offers a glimpse into the promising developments in the years to come.
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Affiliation(s)
- Cosimo Jann
- Biocenter, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- IMB Postdoc Programme (IPPro), 55128 Mainz, Germany
| | - Sabrina Giofré
- Biocenter, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- IMB Postdoc Programme (IPPro), 55128 Mainz, Germany
| | - Rajanya Bhattacharjee
- Biocenter, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- IMB International PhD Programme (IPP), 55128 Mainz, Germany
| | - Edward A Lemke
- Biocenter, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany
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6
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Larizza L, Colombo EA. Interdependence between Nuclear Pore Gatekeepers and Genome Caretakers: Cues from Genome Instability Syndromes. Int J Mol Sci 2024; 25:9387. [PMID: 39273335 PMCID: PMC11394955 DOI: 10.3390/ijms25179387] [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: 08/01/2024] [Revised: 08/24/2024] [Accepted: 08/27/2024] [Indexed: 09/15/2024] Open
Abstract
This review starts off with the first germline homozygous variants of the Nucleoporin 98 gene (NUP98) in siblings whose clinical presentation recalls Rothmund-Thomson (RTS) and Werner (WS) syndromes. The progeroid phenotype caused by a gene associated with haematological malignancies and neurodegenerative disorders primed the search for interplay between caretakers involved in genome instability syndromes and Nuclear Pore Complex (NPC) components. In the context of basic information on NPC architecture and functions, we discuss the studies on the interdependence of caretakers and gatekeepers in WS and Hereditary Fibrosing Poikiloderma (POIKTMP), both entering in differential diagnosis with RTS. In WS, the WRN/WRNIP complex interacts with nucleoporins of the Y-complex and NDC1 altering NPC architecture. In POIKTMP, the mutated FAM111B, recruited by the Y-complex's SEC13 and NUP96, interacts with several Nups safeguarding NPC structure. The linkage of both defective caretakers to the NPC highlights the attempt to activate a repair hub at the nuclear periphery to restore the DNA damage. The two separate WS and POIKTMP syndromes are drawn close by the interaction of their damage sensors with the NPC and by the shared hallmark of short fragile telomeres disclosing a major role of both caretakers in telomere maintenance.
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Affiliation(s)
- Lidia Larizza
- Experimental Research Laboratory of Medical Cytogenetics and Molecular Genetics, IRCCS Istituto Auxologico Italiano, Via Ariosto 13, 20145 Milan, Italy
| | - Elisa Adele Colombo
- Genetica Medica, Dipartimento di Scienze Della Salute, Università Degli Studi di Milano, 20142 Milano, Italy
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7
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Fuxreiter M. Context-dependent, fuzzy protein interactions: Towards sequence-based insights. Curr Opin Struct Biol 2024; 87:102834. [PMID: 38759297 DOI: 10.1016/j.sbi.2024.102834] [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: 01/25/2024] [Revised: 04/11/2024] [Accepted: 04/22/2024] [Indexed: 05/19/2024]
Abstract
Predicting protein interactions in the cellular environment still remains a challenge in the AlphaFold era. Protein interactions, similarly to their structures, sample a continuum from ordered to disordered states, with specific partners in many bound configurations. A multiplicity of binding modes (MBM) enables transition between these states under different cellular conditions. This review focuses on how the cellular environment affects protein interactions, highlighting the molecular mechanisms, biophysical origin, and sequence-based principles of context-dependent, fuzzy interactions. It summarises experimental and computational approaches to address the challenge of interaction heterogeneity and its contribution to a wide range of biological functions. These insights will help in understanding complex cellular processes, involving conversions between protein assembly states, such as from liquid-like droplet state to the amyloid state.
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Affiliation(s)
- Monika Fuxreiter
- Department of Biomedical Sciences, University of Padova, Padova, Italy; Department of Physics and Astronomy, University of Padova, Padova, Italy.
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8
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Joshi A, Avni A, Walimbe A, Rai SK, Sarkar S, Mukhopadhyay S. Hydrogen-Bonded Network of Water in Phase-Separated Biomolecular Condensates. J Phys Chem Lett 2024; 15:7724-7734. [PMID: 39042834 DOI: 10.1021/acs.jpclett.4c01153] [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: 07/25/2024]
Abstract
Biomolecular condensates formed via phase separation of intrinsically disordered proteins/regions (IDPs/IDRs) and nucleic acids are associated with cell physiology and disease. Water makes up for ∼60-70% of the condensate volume and is thought to influence the complex interplay of chain-chain and chain-solvent interactions, modulating the mesoscale properties of condensates. The behavior of water in condensates and the key roles of protein hydration water in driving the phase separation remain elusive. Here, we employ single-droplet vibrational Raman spectroscopy to illuminate the structural redistribution within protein hydration water during the phase separation of neuronal IDPs. Our Raman measurements reveal the changes in the water hydrogen bonding network during homotypic and heterotypic phase separation governed by various molecular drivers. Such single-droplet water Raman measurements offer a potent generic tool to unmask the intriguing interplay of sequence-encoded chain-chain and chain-solvent interactions governing macromolecular phase separation into membraneless organelles, synthetic condensates, and protocells.
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9
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Ravindran R, Michnick SW. Biomolecular condensates as drivers of membrane trafficking and remodelling. Curr Opin Cell Biol 2024; 89:102393. [PMID: 38936257 DOI: 10.1016/j.ceb.2024.102393] [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: 04/01/2024] [Revised: 06/04/2024] [Accepted: 06/06/2024] [Indexed: 06/29/2024]
Abstract
Membrane remodelling is essential for the trafficking of macromolecules throughout the cell, a process that regulates various aspects of cellular health and pathology. Recent studies implicate the role of biomolecular condensates in regulating multiple steps of the membrane trafficking pathway including but not limited to the organization of the trafficking machinery, dynamic remodeling of membranes, spatial and functional regulation, and response to cellular signals. The implicated proteins contain key structural elements, most notably prion-like domains within intrinsically disordered regions that are necessary for biomolecular condensate formation at fusion sites in processes like endocytic assembly, autophagy, organelle biosynthesis and synaptic vesicle fusion. Experimental and theoretical advances in the field continue to demonstrate that protein condensates can perform mechanical work, the implications of which can be extrapolated to diverse areas of membrane biology.
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Affiliation(s)
- Rini Ravindran
- Département de Biochimie, Université de Montréal, Montreal, Quebec, Canada
| | - Stephen W Michnick
- Département de Biochimie, Université de Montréal, Montreal, Quebec, Canada.
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10
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Sushkin ME, Jung M, Lemke EA. Tuning the Functionality of Designer Translating Organelles with Orthogonal tRNA Synthetase/tRNA Pairs. J Mol Biol 2024:168728. [PMID: 39089364 DOI: 10.1016/j.jmb.2024.168728] [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: 06/08/2024] [Revised: 07/22/2024] [Accepted: 07/25/2024] [Indexed: 08/03/2024]
Abstract
Site-specific incorporation of noncanonical amino acids (ncAAs) can be realized by genetic code expansion (GCE) technology. Different orthogonal tRNA synthetase/tRNA (RS/tRNA) pairs have been developed to introduce a ncAA at the desired site, delivering a wide variety of functionalities that can be installed into selected proteins. Cytoplasmic expression of RS/tRNA pairs can cause a problem with background ncAA incorporation into host proteins. The application of orthogonally translating organelles (OTOs), inspired by the concept of phase separation, provides a solution for this issue in mammalian cells, allowing site-specific and protein-selective ncAA incorporation. So far, only Methanosarcina mazei (Mm) pyrrolysyl-tRNA synthetase (PylRS) has been used within OTOs, limiting the method's potential. Here, we explored the implementation of four other widely used orthogonal RS/tRNA pairs with OTOs, which, to our surprise, were unsuccessful in generating mRNA-selective GCE. Next, we tested several experimental solutions and developed a new chimeric phenylalanyl-RS/tRNA pair that enables ncAA incorporation in OTOs in a site-specific and protein-selective manner. Our work reveals unaccounted design constraints in the spatial engineering of enzyme functions using designer organelles and presents a strategy to overcome those in vivo. We then discuss current limitations and future directions of in-cell engineering in general and protein engineering using GCE specifically.
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Affiliation(s)
- Mikhail E Sushkin
- Biocenter, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany; International PhD Programme of the Institute of Molecular Biology (IMB) gGmbH, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Marius Jung
- Biocenter, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany; Biocenter, IMPRS on Cellular Biophysics, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Edward A Lemke
- Biocenter, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany; Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, 55128 Mainz, Germany.
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11
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Shi S, Zhao L, Lu ZY. Coarse-Grained Modeling of Liquid-Liquid Phase Separation in Cells: Challenges and Opportunities. J Phys Chem Lett 2024; 15:7280-7287. [PMID: 38979955 DOI: 10.1021/acs.jpclett.4c01261] [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: 07/10/2024]
Abstract
Liquid-liquid phase separation (LLPS) within cells gives rise to membraneless organelles, which play pivotal roles in numerous cellular functions. A comprehensive understanding of the functional aspects of intrinsically disordered protein (IDP) condensates necessitates elucidating their inherent structures and establishing correlations with biological functions. Coarse-grained (CG) molecular dynamics (MD) simulations present a promising avenue for gaining insights into LLPS mechanisms of biomacromolecules. Essential to this endeavor is the development of tailored CG force fields for MD simulations, incorporating the full spectrum of biomolecules involved in the formation of condensates and accounting for real-time biochemical reactions coupled to the LLPS. Moreover, developing accurate theoretical frameworks and establishing links between condensate structure and its function are imperative for a thorough comprehension of LLPS of biological systems.
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Affiliation(s)
- Shaokang Shi
- College of Chemistry, Jilin University, Changchun 130012, China
| | - Li Zhao
- School of Life Sciences, Jilin University, Changchun 130012, China
| | - Zhong-Yuan Lu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
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12
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Ikliptikawati DK, Makiyama K, Hazawa M, Wong RW. Unlocking the Gateway: The Spatio-Temporal Dynamics of the p53 Family Driven by the Nuclear Pores and Its Implication for the Therapeutic Approach in Cancer. Int J Mol Sci 2024; 25:7465. [PMID: 39000572 PMCID: PMC11242911 DOI: 10.3390/ijms25137465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 07/03/2024] [Accepted: 07/04/2024] [Indexed: 07/16/2024] Open
Abstract
The p53 family remains a captivating focus of an extensive number of current studies. Accumulating evidence indicates that p53 abnormalities rank among the most prevalent in cancer. Given the numerous existing studies, which mostly focus on the mutations, expression profiles, and functional perturbations exhibited by members of the p53 family across diverse malignancies, this review will concentrate more on less explored facets regarding p53 activation and stabilization by the nuclear pore complex (NPC) in cancer, drawing on several studies. p53 integrates a broad spectrum of signals and is subject to diverse regulatory mechanisms to enact the necessary cellular response. It is widely acknowledged that each stage of p53 regulation, from synthesis to degradation, significantly influences its functionality in executing specific tasks. Over recent decades, a large body of data has established that mechanisms of regulation, closely linked with protein activation and stabilization, involve intricate interactions with various cellular components. These often transcend canonical regulatory pathways. This new knowledge has expanded from the regulation of genes themselves to epigenomics and proteomics, whereby interaction partners increase in number and complexity compared with earlier paradigms. Specifically, studies have recently shown the involvement of the NPC protein in such complex interactions, underscoring the further complexity of p53 regulation. Furthermore, we also discuss therapeutic strategies based on recent developments in this field in combination with established targeted therapies.
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Affiliation(s)
- Dini Kurnia Ikliptikawati
- Cell-Bionomics Research Unit, Innovative Integrated Bio-Research Core, Institute for Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa 9201192, Japan;
| | - Kei Makiyama
- Laboratory of Molecular Cell Biology, Division of Transdisciplinary Sciences, Graduate School of Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa 9201192, Japan
| | - Masaharu Hazawa
- Cell-Bionomics Research Unit, Innovative Integrated Bio-Research Core, Institute for Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa 9201192, Japan;
- Laboratory of Molecular Cell Biology, Division of Transdisciplinary Sciences, Graduate School of Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa 9201192, Japan
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 9201192, Japan
| | - Richard W. Wong
- Cell-Bionomics Research Unit, Innovative Integrated Bio-Research Core, Institute for Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa 9201192, Japan;
- Laboratory of Molecular Cell Biology, Division of Transdisciplinary Sciences, Graduate School of Frontier Science Initiative, Kanazawa University, Kakuma-machi, Kanazawa 9201192, Japan
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 9201192, Japan
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13
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Modak A, Kilic Z, Chattrakun K, Terry DS, Kalathur RC, Blanchard SC. Single-Molecule Imaging of Integral Membrane Protein Dynamics and Function. Annu Rev Biophys 2024; 53:427-453. [PMID: 39013028 DOI: 10.1146/annurev-biophys-070323-024308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Integral membrane proteins (IMPs) play central roles in cellular physiology and represent the majority of known drug targets. Single-molecule fluorescence and fluorescence resonance energy transfer (FRET) methods have recently emerged as valuable tools for investigating structure-function relationships in IMPs. This review focuses on the practical foundations required for examining polytopic IMP function using single-molecule FRET (smFRET) and provides an overview of the technical and conceptual frameworks emerging from this area of investigation. In this context, we highlight the utility of smFRET methods to reveal transient conformational states critical to IMP function and the use of smFRET data to guide structural and drug mechanism-of-action investigations. We also identify frontiers where progress is likely to be paramount to advancing the field.
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Affiliation(s)
- Arnab Modak
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA; , , , , ,
| | - Zeliha Kilic
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA; , , , , ,
| | - Kanokporn Chattrakun
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA; , , , , ,
| | - Daniel S Terry
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA; , , , , ,
| | - Ravi C Kalathur
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA; , , , , ,
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA; , , , , ,
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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14
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Ibáñez de Opakua A, Pantoja CF, Cima-Omori MS, Dienemann C, Zweckstetter M. Impact of distinct FG nucleoporin repeats on Nup98 self-association. Nat Commun 2024; 15:3797. [PMID: 38714656 PMCID: PMC11076500 DOI: 10.1038/s41467-024-48194-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 04/24/2024] [Indexed: 05/10/2024] Open
Abstract
Nucleoporins rich in phenylalanine/glycine (FG) residues form the permeability barrier within the nuclear pore complex and are implicated in several pathological cellular processes, including oncogenic fusion condensates. The self-association of FG-repeat proteins and interactions between FG-repeats play a critical role in these activities by forming hydrogel-like structures. Here we show that mutation of specific FG repeats of Nup98 can strongly decrease the protein's self-association capabilities. We further present a cryo-electron microscopy structure of a Nup98 peptide fibril with higher stability per residue compared with previous Nup98 fibril structures. The high-resolution structure reveals zipper-like hydrophobic patches which contain a GLFG motif and are less compatible for binding to nuclear transport receptors. The identified distinct molecular properties of different regions of the nucleoporin may contribute to spatial variations in the self-association of FG-repeats, potentially influencing transport processes through the nuclear pore.
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Affiliation(s)
- Alain Ibáñez de Opakua
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, Göttingen, Germany
| | - Christian F Pantoja
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, Göttingen, Germany
| | - Maria-Sol Cima-Omori
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, Göttingen, Germany
| | - Christian Dienemann
- Max Planck Institute for Multidisciplinary Sciences, Department of Molecular Biology, Am Fassberg 11, Göttingen, Germany
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, Göttingen, Germany.
- Max Planck Institute for Multidisciplinary Sciences, Department of NMR-based Structural Biology, Am Fassberg 11, Göttingen, Germany.
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15
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Bergeron JJM. Proteomics Impact on Cell Biology to Resolve Cell Structure and Function. Mol Cell Proteomics 2024; 23:100758. [PMID: 38574860 PMCID: PMC11070594 DOI: 10.1016/j.mcpro.2024.100758] [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: 02/07/2024] [Revised: 03/23/2024] [Accepted: 03/26/2024] [Indexed: 04/06/2024] Open
Abstract
The acceleration of advances in proteomics has enabled integration with imaging at the EM and light microscopy levels, cryo-EM of protein structures, and artificial intelligence with proteins comprehensively and accurately resolved for cell structures at nanometer to subnanometer resolution. Proteomics continues to outpace experimentally based structural imaging, but their ultimate integration is a path toward the goal of a compendium of all proteins to understand mechanistically cell structure and function.
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Affiliation(s)
- John J M Bergeron
- Department of Medicine, McGill University Hospital Research Institute, Montreal, Quebec, Canada.
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16
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Sun C. Single-Molecule-Resolution Approaches in Synaptic Biology. J Phys Chem B 2024; 128:3061-3068. [PMID: 38513216 DOI: 10.1021/acs.jpcb.3c08026] [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: 03/23/2024]
Abstract
Synapses between neurons are the primary loci for information transfer and storage in the brain. An individual neuron, alone, can make over 10000 synaptic contacts. It is, however, not easy to investigate what goes on locally within a synapse because many synaptic compartments are only a few hundred nanometers wide in size─close to the diffraction limit of light. To observe the biomolecular machinery and processes within synapses, in situ single-molecule techniques are emerging as powerful tools. Guided by important biological questions, this Perspective will highlight recent advances in using these techniques to obtain in situ measurements of synaptic molecules in three aspects: the cell-biological machinery within synapses, the synaptic architecture, and the synaptic neurotransmitter receptors. These advances showcase the increasing importance of single-molecule-resolution techniques for accessing subcellular biophysical and biomolecular information related to the brain.
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Affiliation(s)
- Chao Sun
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, 8000 Aarhus C, Denmark
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17
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Fischer AAM, Robertson HB, Kong D, Grimm MM, Grether J, Groth J, Baltes C, Fliegauf M, Lautenschläger F, Grimbacher B, Ye H, Helms V, Weber W. Engineering Material Properties of Transcription Factor Condensates to Control Gene Expression in Mammalian Cells and Mice. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2311834. [PMID: 38573961 DOI: 10.1002/smll.202311834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/22/2024] [Indexed: 04/06/2024]
Abstract
Phase separation of biomolecules into condensates is a key mechanism in the spatiotemporal organization of biochemical processes in cells. However, the impact of the material properties of biomolecular condensates on important processes, such as the control of gene expression, remains largely elusive. Here, the material properties of optogenetically induced transcription factor condensates are systematically tuned, and probed for their impact on the activation of target promoters. It is demonstrated that transcription factors in rather liquid condensates correlate with increased gene expression levels, whereas stiffer transcription factor condensates correlate with the opposite effect, reduced activation of gene expression. The broad nature of these findings is demonstrated in mammalian cells and mice, as well as by using different synthetic and natural transcription factors. These effects are observed for both transgenic and cell-endogenous promoters. The findings provide a novel materials-based layer in the control of gene expression, which opens novel opportunities in optogenetic engineering and synthetic biology.
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Affiliation(s)
- Alexandra A M Fischer
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Albertstraße 21a, 79104, Freiburg, Germany
- INM - Leibniz Institute for New Materials, Campus D2 2, 66123, Saarbrücken, Germany
| | - Hanah B Robertson
- Center for Bioinformatics, Saarland Informatics Campus, Saarland University, 66123, Saarbrücken, Germany
| | - Deqiang Kong
- Synthetic Biology and Biomedical Engineering Laboratory, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai, 200241, China
| | - Merlin M Grimm
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
| | - Jakob Grether
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
- Biberach University of Applied Sciences, Karlstraße 6-11, 88400, Biberach an der Riß, Germany
| | - Johanna Groth
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
| | - Carsten Baltes
- Department of Experimental Physics and Center for Biophysics, Saarland University, 66123, Saarbrücken, Germany
| | - Manfred Fliegauf
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), Medical Center, Faculty of Medicine, University of Freiburg, Breisacherstr. 115, 79106, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
| | - Franziska Lautenschläger
- Department of Experimental Physics and Center for Biophysics, Saarland University, 66123, Saarbrücken, Germany
| | - Bodo Grimbacher
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency (CCI), Medical Center, Faculty of Medicine, University of Freiburg, Breisacherstr. 115, 79106, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
- DZIF - German Center for Infection Research, Deutsches Zentrum für Infektionsforschung e.V., Inhoffenstr. 7, 38124, Braunschweig, Germany
- RESIST - Cluster of Excellence 2155 to Hanover Medical School, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Haifeng Ye
- Synthetic Biology and Biomedical Engineering Laboratory, Biomedical Synthetic Biology Research Center, Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Dongchuan Road 500, Shanghai, 200241, China
| | - Volkhard Helms
- Center for Bioinformatics, Saarland Informatics Campus, Saarland University, 66123, Saarbrücken, Germany
| | - Wilfried Weber
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Albertstraße 21a, 79104, Freiburg, Germany
- INM - Leibniz Institute for New Materials, Campus D2 2, 66123, Saarbrücken, Germany
- Department of Materials Science and Engineering, Campus D2 2, Saarland University, 66123, Saarbrücken, Germany
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18
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Lemke EA, Babu MM, Kriwacki RW, Mittag T, Pappu RV, Wright PE, Forman-Kay JD. Intrinsic disorder: A term to define the specific physicochemical characteristic of protein conformational heterogeneity. Mol Cell 2024; 84:1188-1190. [PMID: 38579677 DOI: 10.1016/j.molcel.2024.02.024] [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: 02/19/2024] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 04/07/2024]
Abstract
In his commentary in this issue of Molecular Cell,1 Struhl reasons that the term "intrinsically disordered regions" represents a vague and confusing concept for protein function. However, the term "intrinsically disordered" highlights the important physicochemical characteristic of conformational heterogeneity. Thus, "intrinsically disordered" is the counterpart to the term "folded, " with neither term having specific functional implications.
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Affiliation(s)
- Edward A Lemke
- Biocenter, Johannes Gutenberg University, Hanns-Dieter-Hüsch Weg 17, 55128 Mainz, Germany; Institute for Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.
| | - M Madan Babu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA; Center of Excellence for Data Driven Discovery, Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - Richard W Kriwacki
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA; Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN, USA.
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Biomolecular Condensates, Washington University in St. Louis, St. Louis, MO 63130, USA.
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Julie D Forman-Kay
- Molecular Medicine Program, Hospital for Sick Children, Toronto ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto ON M5S 1A8, Canada.
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19
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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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20
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Holehouse AS, Kragelund BB. The molecular basis for cellular function of intrinsically disordered protein regions. Nat Rev Mol Cell Biol 2024; 25:187-211. [PMID: 37957331 DOI: 10.1038/s41580-023-00673-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2023] [Indexed: 11/15/2023]
Abstract
Intrinsically disordered protein regions exist in a collection of dynamic interconverting conformations that lack a stable 3D structure. These regions are structurally heterogeneous, ubiquitous and found across all kingdoms of life. Despite the absence of a defined 3D structure, disordered regions are essential for cellular processes ranging from transcriptional control and cell signalling to subcellular organization. Through their conformational malleability and adaptability, disordered regions extend the repertoire of macromolecular interactions and are readily tunable by their structural and chemical context, making them ideal responders to regulatory cues. Recent work has led to major advances in understanding the link between protein sequence and conformational behaviour in disordered regions, yet the link between sequence and molecular function is less well defined. Here we consider the biochemical and biophysical foundations that underlie how and why disordered regions can engage in productive cellular functions, provide examples of emerging concepts and discuss how protein disorder contributes to intracellular information processing and regulation of cellular function.
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Affiliation(s)
- Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, MO, USA.
- Center for Biomolecular Condensates, Washington University in St Louis, St Louis, MO, USA.
| | - Birthe B Kragelund
- REPIN, Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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21
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Kozma E, Kele P. Bioorthogonal Reactions in Bioimaging. Top Curr Chem (Cham) 2024; 382:7. [PMID: 38400853 PMCID: PMC10894152 DOI: 10.1007/s41061-024-00452-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/22/2024] [Indexed: 02/26/2024]
Abstract
Visualization of biomolecules in their native environment or imaging-aided understanding of more complex biomolecular processes are one of the focus areas of chemical biology research, which requires selective, often site-specific labeling of targets. This challenging task is effectively addressed by bioorthogonal chemistry tools in combination with advanced synthetic biology methods. Today, the smart combination of the elements of the bioorthogonal toolbox allows selective installation of multiple markers to selected targets, enabling multicolor or multimodal imaging of biomolecules. Furthermore, recent developments in bioorthogonally applicable probe design that meet the growing demands of superresolution microscopy enable more complex questions to be addressed. These novel, advanced probes enable highly sensitive, low-background, single- or multiphoton imaging of biological species and events in live organisms at resolutions comparable to the size of the biomolecule of interest. Herein, the latest developments in bioorthogonal fluorescent probe design and labeling schemes will be discussed in the context of in cellulo/in vivo (multicolor and/or superresolved) imaging schemes. The second part focuses on the importance of genetically engineered minimal bioorthogonal tags, with a particular interest in site-specific protein tagging applications to answer biological questions.
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Affiliation(s)
- Eszter Kozma
- Chemical Biology Research Group, Institute of Organic Chemistry, HUN-REN Research Centre for Natural Sciences, Magyar Tudósok Krt. 2, Budapest, 1117, Hungary
| | - Péter Kele
- Chemical Biology Research Group, Institute of Organic Chemistry, HUN-REN Research Centre for Natural Sciences, Magyar Tudósok Krt. 2, Budapest, 1117, Hungary.
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22
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Dickson CF, Hertel S, Tuckwell AJ, Li N, Ruan J, Al-Izzi SC, Ariotti N, Sierecki E, Gambin Y, Morris RG, Towers GJ, Böcking T, Jacques DA. The HIV capsid mimics karyopherin engagement of FG-nucleoporins. Nature 2024; 626:836-842. [PMID: 38267582 PMCID: PMC10881392 DOI: 10.1038/s41586-023-06969-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 12/13/2023] [Indexed: 01/26/2024]
Abstract
HIV can infect non-dividing cells because the viral capsid can overcome the selective barrier of the nuclear pore complex and deliver the genome directly into the nucleus1,2. Remarkably, the intact HIV capsid is more than 1,000 times larger than the size limit prescribed by the diffusion barrier of the nuclear pore3. This barrier in the central channel of the nuclear pore is composed of intrinsically disordered nucleoporin domains enriched in phenylalanine-glycine (FG) dipeptides. Through multivalent FG interactions, cellular karyopherins and their bound cargoes solubilize in this phase to drive nucleocytoplasmic transport4. By performing an in vitro dissection of the nuclear pore complex, we show that a pocket on the surface of the HIV capsid similarly interacts with FG motifs from multiple nucleoporins and that this interaction licences capsids to penetrate FG-nucleoporin condensates. This karyopherin mimicry model addresses a key conceptual challenge for the role of the HIV capsid in nuclear entry and offers an explanation as to how an exogenous entity much larger than any known cellular cargo may be able to non-destructively breach the nuclear envelope.
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Affiliation(s)
- C F Dickson
- Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - S Hertel
- Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - A J Tuckwell
- Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - N Li
- Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - J Ruan
- Electron Microscope Unit, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - S C Al-Izzi
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- School of Physics, University of New South Wales, Sydney, New South Wales, Australia
| | - N Ariotti
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - E Sierecki
- Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Y Gambin
- Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - R G Morris
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- School of Physics, University of New South Wales, Sydney, New South Wales, Australia
| | - G J Towers
- Infection and Immunity, University College London, London, UK
| | - T Böcking
- Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - D A Jacques
- Department of Molecular Medicine, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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23
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Beck M, Covino R, Hänelt I, Müller-McNicoll M. Understanding the cell: Future views of structural biology. Cell 2024; 187:545-562. [PMID: 38306981 DOI: 10.1016/j.cell.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/05/2023] [Accepted: 12/11/2023] [Indexed: 02/04/2024]
Abstract
Determining the structure and mechanisms of all individual functional modules of cells at high molecular detail has often been seen as equal to understanding how cells work. Recent technical advances have led to a flush of high-resolution structures of various macromolecular machines, but despite this wealth of detailed information, our understanding of cellular function remains incomplete. Here, we discuss present-day limitations of structural biology and highlight novel technologies that may enable us to analyze molecular functions directly inside cells. We predict that the progression toward structural cell biology will involve a shift toward conceptualizing a 4D virtual reality of cells using digital twins. These will capture cellular segments in a highly enriched molecular detail, include dynamic changes, and facilitate simulations of molecular processes, leading to novel and experimentally testable predictions. Transferring biological questions into algorithms that learn from the existing wealth of data and explore novel solutions may ultimately unveil how cells work.
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Affiliation(s)
- Martin Beck
- Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany; Goethe University Frankfurt, Frankfurt, Germany.
| | - Roberto Covino
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany.
| | - Inga Hänelt
- Goethe University Frankfurt, Frankfurt, Germany.
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24
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Sipko EL, Chappell GF, Berlow RB. Multivalency emerges as a common feature of intrinsically disordered protein interactions. Curr Opin Struct Biol 2024; 84:102742. [PMID: 38096754 DOI: 10.1016/j.sbi.2023.102742] [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: 09/18/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 02/09/2024]
Abstract
Intrinsically disordered proteins (IDPs) use their unique molecular properties and conformational plasticity to interact with cellular partners in a wide variety of biological contexts. Multivalency is an important feature of IDPs that allows for utilization of an expanded toolkit for interactions with other macromolecules and confers additional complexity to molecular recognition processes. Recent studies have offered insights into how multivalent interactions of IDPs enable responsive and sensitive regulation in the context of transcription and cellular signaling. Multivalency is also widely recognized as an important feature of IDP interactions that mediate formation of biomolecular condensates. We highlight recent examples of multivalent interactions of IDPs across diverse contexts to illustrate the breadth of biological processes that utilize multivalency in molecular interactions.
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Affiliation(s)
- Emily L Sipko
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Garrett F Chappell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rebecca B Berlow
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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25
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Hudait A, Voth GA. HIV-1 capsid shape, orientation, and entropic elasticity regulate translocation into the nuclear pore complex. Proc Natl Acad Sci U S A 2024; 121:e2313737121. [PMID: 38241438 PMCID: PMC10823262 DOI: 10.1073/pnas.2313737121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 12/06/2023] [Indexed: 01/21/2024] Open
Abstract
Nuclear import and uncoating of the viral capsid are critical steps in the HIV-1 life cycle that serve to transport and release genomic material into the nucleus. Viral core import involves translocating the HIV-1 capsid at the nuclear pore complex (NPC). Notably, the central channel of the NPC appears to often accommodate and allow passage of intact HIV-1 capsid, though mechanistic details of the process remain to be fully understood. Here, we investigate the molecular interactions that operate in concert between the HIV-1 capsid and the NPC that regulate capsid translocation through the central channel. To this end, we develop a "bottom-up" coarse-grained (CG) model of the human NPC from recently released cryo-electron tomography structure and then construct composite membrane-embedded CG NPC models. We find that successful translocation from the cytoplasmic side to the NPC central channel is contingent on the compatibility of the capsid morphology and channel dimension and the proper orientation of the capsid approach to the channel from the cytoplasmic side. The translocation dynamics is driven by maximizing the contacts between phenylalanine-glycine nucleoporins at the central channel and the capsid. For the docked intact capsids, structural analysis reveals correlated striated patterns of lattice disorder likely related to the intrinsic capsid elasticity. Uncondensed genomic material inside the docked capsid augments the overall lattice disorder of the capsid. Our results suggest that the intrinsic "elasticity" can also aid the capsid to adapt to the stress and remain structurally intact during translocation.
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Affiliation(s)
- Arpa Hudait
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, IL60637
| | - Gregory A. Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, IL60637
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26
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Khalil B, Linsenmeier M, Smith CL, Shorter J, Rossoll W. Nuclear-import receptors as gatekeepers of pathological phase transitions in ALS/FTD. Mol Neurodegener 2024; 19:8. [PMID: 38254150 PMCID: PMC10804745 DOI: 10.1186/s13024-023-00698-1] [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: 06/05/2023] [Accepted: 12/13/2023] [Indexed: 01/24/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative disorders on a disease spectrum that are characterized by the cytoplasmic mislocalization and aberrant phase transitions of prion-like RNA-binding proteins (RBPs). The common accumulation of TAR DNA-binding protein-43 (TDP-43), fused in sarcoma (FUS), and other nuclear RBPs in detergent-insoluble aggregates in the cytoplasm of degenerating neurons in ALS/FTD is connected to nuclear pore dysfunction and other defects in the nucleocytoplasmic transport machinery. Recent advances suggest that beyond their canonical role in the nuclear import of protein cargoes, nuclear-import receptors (NIRs) can prevent and reverse aberrant phase transitions of TDP-43, FUS, and related prion-like RBPs and restore their nuclear localization and function. Here, we showcase the NIR family and how they recognize cargo, drive nuclear import, and chaperone prion-like RBPs linked to ALS/FTD. We also discuss the promise of enhancing NIR levels and developing potentiated NIR variants as therapeutic strategies for ALS/FTD and related neurodegenerative proteinopathies.
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Affiliation(s)
- Bilal Khalil
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, U.S.A
| | - Miriam Linsenmeier
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, U.S.A
| | - Courtney L Smith
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, U.S.A
- Mayo Clinic Graduate School of Biomedical Sciences, Neuroscience Track, Mayo Clinic, Jacksonville, FL, 32224, U.S.A
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, U.S.A..
| | - Wilfried Rossoll
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, U.S.A..
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27
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Raveh B, Eliasian R, Rashkovits S, Russel D, Hayama R, Sparks SE, Singh D, Lim R, Villa E, Rout MP, Cowburn D, Sali A. Integrative spatiotemporal map of nucleocytoplasmic transport. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.31.573409. [PMID: 38260487 PMCID: PMC10802240 DOI: 10.1101/2023.12.31.573409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The Nuclear Pore Complex (NPC) facilitates rapid and selective nucleocytoplasmic transport of molecules as large as ribosomal subunits and viral capsids. It is not clear how key emergent properties of this transport arise from the system components and their interactions. To address this question, we constructed an integrative coarse-grained Brownian dynamics model of transport through a single NPC, followed by coupling it with a kinetic model of Ran-dependent transport in an entire cell. The microscopic model parameters were fitted to reflect experimental data and theoretical information regarding the transport, without making any assumptions about its emergent properties. The resulting reductionist model is validated by reproducing several features of transport not used for its construction, such as the morphology of the central transporter, rates of passive and facilitated diffusion as a function of size and valency, in situ radial distributions of pre-ribosomal subunits, and active transport rates for viral capsids. The model suggests that the NPC functions essentially as a virtual gate whose flexible phenylalanine-glycine (FG) repeat proteins raise an entropy barrier to diffusion through the pore. Importantly, this core functionality is greatly enhanced by several key design features, including 'fuzzy' and transient interactions, multivalency, redundancy in the copy number of FG nucleoporins, exponential coupling of transport kinetics and thermodynamics in accordance with the transition state theory, and coupling to the energy-reliant RanGTP concentration gradient. These design features result in the robust and resilient rate and selectivity of transport for a wide array of cargo ranging from a few kilodaltons to megadaltons in size. By dissecting these features, our model provides a quantitative starting point for rationally modulating the transport system and its artificial mimics.
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28
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Ching C, Maufront J, di Cicco A, Lévy D, Dezi M. C ool-contacts: Cryo-Electron Microscopy of Membrane Contact Sites and Their Components. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2024; 7:25152564241231364. [PMID: 38410695 PMCID: PMC10895918 DOI: 10.1177/25152564241231364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/23/2024] [Indexed: 02/28/2024]
Abstract
Electron microscopy has played a pivotal role in elucidating the ultrastructure of membrane contact sites between cellular organelles. The advent of cryo-electron microscopy has ushered in the ability to determine atomic models of constituent proteins or protein complexes within sites of membrane contact through single particle analysis. Furthermore, it enables the visualization of the three-dimensional architecture of membrane contact sites, encompassing numerous copies of proteins, whether in vitro reconstituted or directly observed in situ using cryo-electron tomography. Nevertheless, there exists a scarcity of cryo-electron microscopy studies focused on the site of membrane contact and their constitutive proteins. This review provides an overview of the contributions made by cryo-electron microscopy to our understanding of membrane contact sites, outlines the associated limitations, and explores prospects in this field.
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Affiliation(s)
- Cyan Ching
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Julien Maufront
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Aurélie di Cicco
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Daniel Lévy
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Manuela Dezi
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
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29
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Stankunas E, Köhler A. The interplay of nuclear pores and lipids. Curr Opin Cell Biol 2023; 85:102251. [PMID: 37804774 DOI: 10.1016/j.ceb.2023.102251] [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: 05/08/2023] [Revised: 08/24/2023] [Accepted: 09/07/2023] [Indexed: 10/09/2023]
Abstract
Nuclear pore complexes (NPCs) mediate the bidirectional transport of cargo across the nuclear envelope (NE). NPCs are also membrane remodeling machines with a capacity to curve and fuse the membranes of the NE. However, little is known about the interplay of NPCs and lipids at a mechanistic level. A full understanding of NPC structure and function needs to encompass how the NPC shapes membranes and is itself shaped by lipids. Here we attempt to connect recent findings in NPC research with the broader field of membrane biochemistry to illustrate how an interplay between NPCs and lipids may facilitate the conformational plasticity of NPCs and the generation of a unique pore membrane topology. We highlight the need to better understand the NPC's lipid environment and outline experimental avenues towards that goal.
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Affiliation(s)
- Edvinas Stankunas
- Max Perutz Labs, University of Vienna and Medical University of Vienna, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 9/3, 1030 Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, A-1030 Vienna, Austria
| | - Alwin Köhler
- Max Perutz Labs, University of Vienna and Medical University of Vienna, Vienna Biocenter Campus (VBC), Dr. Bohr-Gasse 9/3, 1030 Vienna, Austria.
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30
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Barrientos ECR, Otto TA, Mouton SN, Steen A, Veenhoff LM. A survey of the specificity and mechanism of 1,6 hexanediol-induced disruption of nuclear transport. Nucleus 2023; 14:2240139. [PMID: 37498221 PMCID: PMC10376917 DOI: 10.1080/19491034.2023.2240139] [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: 03/30/2023] [Revised: 07/17/2023] [Accepted: 07/19/2023] [Indexed: 07/28/2023] Open
Abstract
Selective transport through the nuclear pore complex (NPC) depends on the dynamic binding of FG-repeat containing nucleoporins, the FG-nups, with each other and with Karyopherins (Kaps). Here, we assessed the specificity and mechanism by which the aliphatic alcohol 1,6-hexanediol (1,6HD) disrupts the permeability barrier of NPCs in live baker's yeast cells. After a 10-minute exposure to 5% 1,6HD, no notable changes were observed in cell growth, cytosolic pH and ATP levels, or the appearance of organelles. However, effects on the cytoskeleton and Hsp104 were noted. 1,6HD clearly affected the NPC permeability barrier, allowing passive nuclear entry of a 177kDa reporter protein that is normally confined to the cytosol. Moreover, multiple Kaps were displaced from NPCs, and the displacement of Kap122-GFP correlated with the observed passive permeability changes. 1,6HD thus temporarily permeates NPCs, and in line with Kap-centric models, the mechanism includes the release of numerous Kaps from the NPCs.
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Affiliation(s)
- Elizabeth C Riquelme Barrientos
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
| | - Tegan A Otto
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
| | - Sara N Mouton
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
| | - Anton Steen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
| | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, Groningen, The Netherlands
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31
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Wang J, Devarajan DS, Nikoubashman A, Mittal J. Conformational Properties of Polymers at Droplet Interfaces as Model Systems for Disordered Proteins. ACS Macro Lett 2023; 12:1472-1478. [PMID: 37856873 PMCID: PMC10771815 DOI: 10.1021/acsmacrolett.3c00456] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 10/03/2023] [Indexed: 10/21/2023]
Abstract
Polymer models serve as useful tools for studying the formation and physical properties of biomolecular condensates. In recent years, the interface dividing the dense and dilute phases of condensates has been discovered to be closely related to their functionality, but the conformational preferences of the constituent proteins remain unclear. To elucidate this, we perform molecular simulations of a droplet formed by phase separation of homopolymers as a surrogate model for the prion-like low-complexity domains. By systematically analyzing the polymer conformations at different locations in the droplet, we find that the chains become compact at the droplet interface compared with the droplet interior. Further, segmental analysis revealed that the end sections of the chains are enriched at the interface to maximize conformational entropy and are more expanded than the middle sections of the chains. We find that the majority of chain segments lie tangential to the droplet surface, and only the chain ends tend to align perpendicular to the interface. These trends also hold for the natural proteins FUS LC and LAF-1 RGG, which exhibit more compact chain conformations at the interface compared to the droplet interior. Our findings provide important insights into the interfacial properties of biomolecular condensates and highlight the value of using simple polymer physics models to understand the underlying mechanisms.
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Affiliation(s)
- Jiahui Wang
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | | | - Arash Nikoubashman
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Institut für Theoretische Physik, Technische Universität Dresden, 01069 Dresden, Germany
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
- Interdisciplinary Graduate Program in Genetics and Genomics, Texas A&M University, College Station, Texas 77843, United States
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32
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Joshi A, Walimbe A, Avni A, Rai SK, Arora L, Sarkar S, Mukhopadhyay S. Single-molecule FRET unmasks structural subpopulations and crucial molecular events during FUS low-complexity domain phase separation. Nat Commun 2023; 14:7331. [PMID: 37957147 PMCID: PMC10643395 DOI: 10.1038/s41467-023-43225-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 11/03/2023] [Indexed: 11/15/2023] Open
Abstract
Biomolecular condensates formed via phase separation of proteins and nucleic acids are thought to be associated with a wide range of cellular functions and dysfunctions. We dissect critical molecular events associated with phase separation of an intrinsically disordered prion-like low-complexity domain of Fused in Sarcoma by performing single-molecule studies permitting us to access the wealth of molecular information that is skewed in conventional ensemble experiments. Our single-molecule FRET experiments reveal the coexistence of two conformationally distinct subpopulations in the monomeric form. Single-droplet single-molecule FRET studies coupled with fluorescence correlation spectroscopy, picosecond time-resolved fluorescence anisotropy, and vibrational Raman spectroscopy indicate that structural unwinding switches intramolecular interactions into intermolecular contacts allowing the formation of a dynamic network within condensates. A disease-related mutation introduces enhanced structural plasticity engendering greater interchain interactions that can accelerate pathological aggregation. Our findings provide key mechanistic underpinnings of sequence-encoded dynamically-controlled structural unzipping resulting in biological phase separation.
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Affiliation(s)
- Ashish Joshi
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Anuja Walimbe
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Anamika Avni
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Sandeep K Rai
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Lisha Arora
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Snehasis Sarkar
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India
| | - Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India.
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India.
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, SAS Nagar, Mohali, Punjab, 140306, India.
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33
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Boyle E, Wilfling F. Autophagy as a caretaker of nuclear integrity. FEBS Lett 2023; 597:2728-2738. [PMID: 37567863 DOI: 10.1002/1873-3468.14719] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023]
Abstract
Due to their essential functions, dysregulation of nuclear pore complexes (NPCs) is strongly associated with numerous human diseases, including neurodegeneration and cancer. On a cellular level, longevity of scaffold nucleoporins in postmitotic cells of both C. elegans and mammals renders them vulnerable to age-related damage, which is associated with an increase in pore leakiness and accumulation of intranuclear aggregates in rat brain cells. Thus, understanding the mechanisms which underpin the homeostasis of this complex, as well as other nuclear proteins, is essential. In this review, autophagy-mediated degradation pathways governing nuclear components in yeast will be discussed, with a particular focus on NPCs. Furthermore, the various nuclear degradation mechanisms identified thus far in diverse eukaryotes will also be highlighted.
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Affiliation(s)
- Emily Boyle
- Mechanisms of Cellular Quality Control, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Florian Wilfling
- Mechanisms of Cellular Quality Control, Max Planck Institute of Biophysics, Frankfurt, Germany
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34
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Sushkin ME, Koehler C, Lemke EA. Remodeling the cellular stress response for enhanced genetic code expansion in mammalian cells. Nat Commun 2023; 14:6931. [PMID: 37903771 PMCID: PMC10616097 DOI: 10.1038/s41467-023-42689-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/18/2023] [Indexed: 11/01/2023] Open
Abstract
Genetic code expansion (GCE) reprograms the translational machinery to site-specifically incorporate noncanonical amino acids (ncAAs) into a selected protein. The efficiency of GCE in mammalian cells might be compromised by cellular stress responses, among which, the protein kinase R(PKR)-dependent eIF2α phosphorylation pathway can reduce translation rates. Here we test several strategies to engineer the eIF2α pathway and boost the rate of translation and show that such interventions increase GCE efficiency in mammalian cells. In particular, addition of the N-terminal PKR fragment (1-174) provides a substantial enhancement in cytoplasmic GCE and also in GCE realized by OTOs (orthogonally translating designer organelles), which built on the principle of 2D phase separation to enable mRNA-selective ncAA incorporation. Our study demonstrates an approach for improving the efficiency of GCE and provides a means by which the power of designer organelles can be further optimized to tune protein translation.
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Affiliation(s)
- Mikhail E Sushkin
- Biocenter, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany
- International PhD Programme of the Institute of Molecular Biology, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany
| | - Christine Koehler
- Biocenter, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany
- VERAXA Biotech GmbH, Carl-Friedrich-Gauß-Ring 5, 69124, Heidelberg, Germany
| | - Edward A Lemke
- Biocenter, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128, Mainz, Germany.
- Institute of Molecular Biology gGmbH, Ackermannweg 4, 55128, Mainz, Germany.
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35
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Kuiper EFE, Prophet SM, Schlieker C. Coordinating nucleoporin condensation and nuclear pore complex assembly. FEBS Lett 2023; 597:2534-2545. [PMID: 37620293 DOI: 10.1002/1873-3468.14725] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/24/2023] [Accepted: 08/10/2023] [Indexed: 08/26/2023]
Abstract
The nuclear pore complex (NPC) is among the most elaborate protein complexes in eukaryotes. While ribosomes and proteasomes are known to require dedicated assembly machinery, our understanding of NPC assembly is at a relatively early stage. Defects in NPC assembly or homeostasis are tied to movement disorders, including dystonia and amyotrophic lateral sclerosis (ALS), as well as aging, requiring a better understanding of these processes to enable therapeutic intervention. Here, we discuss recent progress in the understanding of NPC assembly and highlight how related defects in human disorders can shed light on NPC biogenesis. We propose that the condensation of phenylalanine-glycine repeat nucleoporins needs to be carefully controlled during NPC assembly to prevent aberrant condensation, aggregation, or amyloid formation.
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Affiliation(s)
- E F Elsiena Kuiper
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA
| | - Sarah M Prophet
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA
| | - Christian Schlieker
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
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36
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Wang J, Sundaravadivelu Devarajan D, Nikoubashman A, Mittal J. Conformational Properties of Polymers at Droplet Interfaces as Model Systems for Disordered Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.29.551102. [PMID: 37577555 PMCID: PMC10418094 DOI: 10.1101/2023.07.29.551102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Polymer models serve as useful tools for studying the formation and physical properties of biomolecular condensates. In recent years, the interface dividing the dense and dilute phases of condensates has been discovered to be closely related to their functionality, but the conformational preferences of the constituent proteins remain unclear. To elucidate this, we perform molecular simulations of a droplet formed by liquid‒liquid phase separation of homopolymers, as a surrogate model for the prion-like low-complexity domains. By systematically analyzing the polymer conformations at different locations in the droplet, we find that the chains become compact at the droplet interface compared to the droplet interior. Further, segmental analysis revealed that the end sections of the chains are enriched at the interface to maximize conformational entropy, and are more expanded than the middle sections of the chains. We find that the majority of chain segments lie tangential to the droplet surface and only the chain ends tend to align perpendicular to the interface. These trends also hold for the natural proteins FUC LC and LAF-1 RGG, which exhibit more compact chain conformations at the interface compared with the droplet interior. Our findings provide important insights into the interfacial properties of biomolecular condensates and highlight the value of using simple polymer physics models to understand the underlying mechanisms.
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Affiliation(s)
- Jiahui Wang
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, United States
| | | | - Arash Nikoubashman
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, United States
- Department of Chemistry, Texas A&M University, College Station, TX 77843, United States
- Interdisciplinary Graduate Program in Genetics and Genomics, Texas A&M University, College Station, TX 77843, United States
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