1
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Shen Y, Ori-McKenney KM. Microtubule-associated protein MAP7 promotes tubulin posttranslational modifications and cargo transport to enable osmotic adaptation. Dev Cell 2024; 59:1553-1570.e7. [PMID: 38574732 DOI: 10.1016/j.devcel.2024.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/11/2023] [Accepted: 03/12/2024] [Indexed: 04/06/2024]
Abstract
Cells remodel their cytoskeletal networks to adapt to their environment. Here, we analyze the mechanisms utilized by the cell to tailor its microtubule landscape in response to changes in osmolarity that alter macromolecular crowding. By integrating live-cell imaging, ex vivo enzymatic assays, and in vitro reconstitution, we probe the impact of cytoplasmic density on microtubule-associated proteins (MAPs) and tubulin posttranslational modifications (PTMs). We find that human epithelial cells respond to fluctuations in cytoplasmic density by modulating microtubule acetylation, detyrosination, or MAP7 association without differentially affecting polyglutamylation, tyrosination, or MAP4 association. These MAP-PTM combinations alter intracellular cargo transport, enabling the cell to respond to osmotic challenges. We further dissect the molecular mechanisms governing tubulin PTM specification and find that MAP7 promotes acetylation and inhibits detyrosination. Our data identify MAP7 in modulating the tubulin code, resulting in microtubule cytoskeleton remodeling and alteration of intracellular transport as an integrated mechanism of cellular adaptation.
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Affiliation(s)
- Yusheng Shen
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Kassandra M Ori-McKenney
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA.
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2
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Monterroso B, Margolin W, Boersma AJ, Rivas G, Poolman B, Zorrilla S. Macromolecular Crowding, Phase Separation, and Homeostasis in the Orchestration of Bacterial Cellular Functions. Chem Rev 2024; 124:1899-1949. [PMID: 38331392 PMCID: PMC10906006 DOI: 10.1021/acs.chemrev.3c00622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/01/2023] [Accepted: 01/10/2024] [Indexed: 02/10/2024]
Abstract
Macromolecular crowding affects the activity of proteins and functional macromolecular complexes in all cells, including bacteria. Crowding, together with physicochemical parameters such as pH, ionic strength, and the energy status, influences the structure of the cytoplasm and thereby indirectly macromolecular function. Notably, crowding also promotes the formation of biomolecular condensates by phase separation, initially identified in eukaryotic cells but more recently discovered to play key functions in bacteria. Bacterial cells require a variety of mechanisms to maintain physicochemical homeostasis, in particular in environments with fluctuating conditions, and the formation of biomolecular condensates is emerging as one such mechanism. In this work, we connect physicochemical homeostasis and macromolecular crowding with the formation and function of biomolecular condensates in the bacterial cell and compare the supramolecular structures found in bacteria with those of eukaryotic cells. We focus on the effects of crowding and phase separation on the control of bacterial chromosome replication, segregation, and cell division, and we discuss the contribution of biomolecular condensates to bacterial cell fitness and adaptation to environmental stress.
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Affiliation(s)
- Begoña Monterroso
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
| | - William Margolin
- Department
of Microbiology and Molecular Genetics, McGovern Medical School, UTHealth-Houston, Houston, Texas 77030, United States
| | - Arnold J. Boersma
- Cellular
Protein Chemistry, Bijvoet Centre for Biomolecular Research, Faculty
of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Germán Rivas
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
| | - Bert Poolman
- Department
of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Silvia Zorrilla
- Department
of Structural and Chemical Biology, Centro de Investigaciones Biológicas
Margarita Salas, Consejo Superior de Investigaciones
Científicas (CSIC), 28040 Madrid, Spain
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3
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Majumdar S, Rastogi H, Chowdhury PK. Bridging Soft Interaction and Excluded Volume in Crowded Milieu through Subtle Protein Dynamics. J Phys Chem B 2024; 128:716-730. [PMID: 38226816 DOI: 10.1021/acs.jpcb.3c07266] [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: 01/17/2024]
Abstract
The impact of macromolecular crowding on biological macromolecules has been elucidated through the excluded volume phenomenon and soft interactions. However, it has often been difficult to provide a clear demarcation between the two regions. Here, using temperature-dependent dynamics (local and global) of the multidomain protein human serum albumin (HSA) in the presence of commonly used synthetic crowders (Dextran 40, PEG 8, Ficoll 70, and Dextran 70), we have shown the presence of a transition that serves as a bridge between the soft and hard regimes. The bridging region is independent of the crowder identity and displays no apparent correlation with the critical overlap concentration of the polymeric crowding agents. Moreover, the dynamics of domains I and II and the protein gating motion respond differently, thereby bringing to the fore the asymmetry underlying the crowder influence on HSA. In addition, solvent-coupled and decoupled protein motions indicate the heterogeneity of the dynamic landscape in the crowded milieu. We also propose an intriguing correlation between protein stability and dynamics, with increased global stability being accompanied by eased local domain motion.
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Affiliation(s)
- Shubhangi Majumdar
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Harshita Rastogi
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Pramit K Chowdhury
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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4
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Holt LJ, Delarue M. Macromolecular crowding: Sensing without a sensor. Curr Opin Cell Biol 2023; 85:102269. [PMID: 37897928 DOI: 10.1016/j.ceb.2023.102269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/28/2023] [Accepted: 10/01/2023] [Indexed: 10/30/2023]
Abstract
All living cells are crowded with macromolecules. Crowding can directly modulate biochemical reactions to various degrees depending on the sizes, shapes, and binding affinities of the reactants. Here, we explore the possibility that cells can sense and adapt to changes in crowding through the widespread modulation of biochemical reactions without the need for a dedicated sensor. Additionally, we explore phase separation as a general physicochemical response to changes in crowding, and a mechanism to both transduce information and physically restore crowding homeostasis.
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Affiliation(s)
- Liam J Holt
- New York University Grossman School of Medicine, Institute for Systems Genetics, New York, NY, USA
| | - Morgan Delarue
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France.
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5
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Arjona MI, Najafi J, Minc N. Cytoplasm mechanics and cellular organization. Curr Opin Cell Biol 2023; 85:102278. [PMID: 37979412 DOI: 10.1016/j.ceb.2023.102278] [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: 07/13/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 11/20/2023]
Abstract
As cells organize spatially or divide, they translocate many micron-scale organelles in their cytoplasm. These include endomembrane vesicles, nuclei, microtubule asters, mitotic spindles, or chromosomes. Organelle motion is powered by cytoskeleton forces but is opposed by viscoelastic forces imparted by the surrounding crowded cytoplasm medium. These resistive forces associated to cytoplasm physcial properties remain generally underappreciated, yet reach significant values to slow down organelle motion or even limit their displacement by springing them back towards their original position. The cytoplasm may also be itself organized in time and space, being for example stiffer or more fluid at certain locations or during particular cell cycle phases. Thus, cytoplasm mechanics may be viewed as a labile module that contributes to organize cells. We here review emerging methods, mechanisms, and concepts to study cytoplasm mechanical properties and their function in organelle positioning, cellular organization and division.
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Affiliation(s)
- María Isabel Arjona
- Université de Paris, CNRS, Institut Jacques Monod, F-75006 Paris, France; Equipe Labellisée LIGUE Contre le Cancer, France
| | - Javad Najafi
- Université de Paris, CNRS, Institut Jacques Monod, F-75006 Paris, France; Equipe Labellisée LIGUE Contre le Cancer, France
| | - Nicolas Minc
- Université de Paris, CNRS, Institut Jacques Monod, F-75006 Paris, France; Equipe Labellisée LIGUE Contre le Cancer, France.
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6
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Emenecker RJ, Guadalupe K, Shamoon NM, Sukenik S, Holehouse AS. Sequence-ensemble-function relationships for disordered proteins in live cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.29.564547. [PMID: 37961106 PMCID: PMC10634935 DOI: 10.1101/2023.10.29.564547] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Intrinsically disordered protein regions (IDRs) are ubiquitous across all kingdoms of life and play a variety of essential cellular roles. IDRs exist in a collection of structurally distinct conformers known as an ensemble. An IDR's amino acid sequence determines its ensemble, which in turn can play an important role in dictating molecular function. Yet a clear link connecting IDR sequence, its ensemble properties, and its molecular function in living cells has not been directly established. Here, we set out to test this sequence-ensemble-function paradigm using a novel computational method (GOOSE) that enables the rational design of libraries of IDRs by systematically varying specific sequence properties. Using ensemble FRET, we measured the ensemble dimensions of a library of rationally designed IDRs in human-derived cell lines, revealing how IDR sequence influences ensemble dimensions in situ. Furthermore, we show that the interplay between sequence and ensemble can tune an IDR's ability to sense changes in cell volume - a de novo molecular function for these synthetic sequences. Our results establish biophysical rules for intracellular sequence-ensemble relationships, enable a new route for understanding how IDR sequences map to function in live cells, and set the ground for the design of synthetic IDRs with de novo function.
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Affiliation(s)
- Ryan J. Emenecker
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO
- Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, MO
| | - Karina Guadalupe
- Department of Chemistry and Biochemistry, University of California, Merced, CA
- Center for Cellular and Biomolecular Machines, University of California, Merced, CA
| | - Nora M. Shamoon
- Center for Cellular and Biomolecular Machines, University of California, Merced, CA
- Quantitative Systems Biology Program, University of California, Merced, CA
| | - Shahar Sukenik
- Department of Chemistry and Biochemistry, University of California, Merced, CA
- Center for Cellular and Biomolecular Machines, University of California, Merced, CA
- Quantitative Systems Biology Program, University of California, Merced, CA
- Health Sciences Research Institute, University of California, Merced, CA
| | - Alex S. Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO
- Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, MO
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7
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Holehouse A, Emenecker R, Guadalupe K, Shamoon N, Sukenik S. Sequence-ensemble-function relationships for disordered proteins in live cells. RESEARCH SQUARE 2023:rs.3.rs-3501110. [PMID: 37986812 PMCID: PMC10659550 DOI: 10.21203/rs.3.rs-3501110/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Intrinsically disordered protein regions (IDRs) are ubiquitous across all kingdoms of life and play a variety of essential cellular roles. IDRs exist in a collection of structurally distinct conformers known as an ensemble. IDR amino acid sequence determines its ensemble, which in turn can play an important role in dictating molecular function. Yet a clear link connecting IDR sequence, its ensemble properties, and its molecular function in living cells has not been systematically established. Here, we set out to test this sequence-ensemble-function paradigm using a novel computational method (GOOSE) that enables the rational design of libraries of IDRs by systematically varying specific sequence properties. Using ensemble FRET, we measured the ensemble dimensions of a library of rationally designed IDRs in human-derived cell lines, revealing how IDR sequence influences ensemble dimensions in situ. Furthermore, we show that the interplay between sequence and ensemble can tune an IDR's ability to sense changes in cell volume - a de novomolecular function for these synthetic sequences. Our results establish biophysical rules for intracellular sequence-ensemble relationships, enable a new route for understanding how IDR sequences map to function in live cells, and set the ground for the design of synthetic IDRs with de novo function.
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8
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Shu T, Mitra G, Alberts J, Viana MP, Levy ED, Hocky GM, Holt LJ. Mesoscale molecular assembly is favored by the active, crowded cytoplasm. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558334. [PMID: 37781612 PMCID: PMC10541124 DOI: 10.1101/2023.09.19.558334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
The mesoscale organization of molecules into membraneless biomolecular condensates is emerging as a key mechanism of rapid spatiotemporal control in cells1. Principles of biomolecular condensation have been revealed through in vitro reconstitution2. However, intracellular environments are much more complex than test-tube environments: They are viscoelastic, highly crowded at the mesoscale, and are far from thermodynamic equilibrium due to the constant action of energy-consuming processes3. We developed synDrops, a synthetic phase separation system, to study how the cellular environment affects condensate formation. Three key features enable physical analysis: synDrops are inducible, bioorthogonal, and have well-defined geometry. This design allows kinetic analysis of synDrop assembly and facilitates computational simulation of the process. We compared experiments and simulations to determine that macromolecular crowding promotes condensate nucleation but inhibits droplet growth through coalescence. ATP-dependent cellular activities help overcome the frustration of growth. In particular, actomyosin dynamics potentiate droplet growth by reducing confinement and elasticity in the mammalian cytoplasm, thereby enabling synDrop coarsening. Our results demonstrate that mesoscale molecular assembly is favored by the combined effects of crowding and active matter in the cytoplasm. These results move toward a better predictive understanding of condensate formation in vivo.
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Affiliation(s)
- Tong Shu
- Institute for Systems Genetics, NYU Langone Medical Center, 435 E 30th Street, New York, NY 10016, USA
| | - Gaurav Mitra
- Department of Chemistry, New York University, New York, New York, USA
| | | | | | - Emmanuel D. Levy
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Glen M. Hocky
- Department of Chemistry, New York University, New York, New York, USA
- Simons Center for Computational Physical Chemistry, New York University, New York, New York, USA
| | - Liam J. Holt
- Institute for Systems Genetics, NYU Langone Medical Center, 435 E 30th Street, New York, NY 10016, USA
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