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Nickaeen M, Berro J, Pollard TD, Slepchenko BM. A model of actin-driven endocytosis explains differences of endocytic motility in budding and fission yeast. Mol Biol Cell 2022; 33:ar16. [PMID: 34910589 PMCID: PMC9250386 DOI: 10.1091/mbc.e21-07-0362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/23/2021] [Accepted: 12/10/2021] [Indexed: 11/15/2022] Open
Abstract
A comparative study (Sun et al., 2019) showed that the abundance of proteins at sites of endocytosis in fission and budding yeast is more similar in the two species than previously thought, yet membrane invaginations in fission yeast elongate twofold faster and are nearly twice as long as in budding yeast. Here we use a three-dimensional model of a motile endocytic invagination (Nickaeen et al., 2019) to investigate factors affecting elongation of the invaginations. We found that differences in turgor pressure in the two yeast species can largely explain the paradoxical differences observed experimentally in endocytic motility.
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Affiliation(s)
- Masoud Nickaeen
- Richard D. Berlin Center for Cell Analysis and Modeling, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, and Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06511, and
- Nanobiology Institute, Yale University, New Haven, CT 06520
| | - Thomas D. Pollard
- Department of Molecular Cellular and Developmental Biology, Yale University
- Department of Molecular Biophysics and Biochemistry, Yale University, and Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06511, and
| | - Boris M. Slepchenko
- Richard D. Berlin Center for Cell Analysis and Modeling, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030
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2
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Bergeron-Sandoval LP, Kumar S, Heris HK, Chang CLA, Cornell CE, Keller SL, François P, Hendricks AG, Ehrlicher AJ, Pappu RV, Michnick SW. Endocytic proteins with prion-like domains form viscoelastic condensates that enable membrane remodeling. Proc Natl Acad Sci U S A 2021; 118:e2113789118. [PMID: 34887356 PMCID: PMC8685726 DOI: 10.1073/pnas.2113789118] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2021] [Indexed: 11/18/2022] Open
Abstract
Membrane invagination and vesicle formation are key steps in endocytosis and cellular trafficking. Here, we show that endocytic coat proteins with prion-like domains (PLDs) form hemispherical puncta in the budding yeast, Saccharomyces cerevisiae These puncta have the hallmarks of biomolecular condensates and organize proteins at the membrane for actin-dependent endocytosis. They also enable membrane remodeling to drive actin-independent endocytosis. The puncta, which we refer to as endocytic condensates, form and dissolve reversibly in response to changes in temperature and solution conditions. We find that endocytic condensates are organized around dynamic protein-protein interaction networks, which involve interactions among PLDs with high glutamine contents. The endocytic coat protein Sla1 is at the hub of the protein-protein interaction network. Using active rheology, we inferred the material properties of endocytic condensates. These experiments show that endocytic condensates are akin to viscoelastic materials. We use these characterizations to estimate the interfacial tension between endocytic condensates and their surroundings. We then adapt the physics of contact mechanics, specifically modifications of Hertz theory, to develop a quantitative framework for describing how interfacial tensions among condensates, the membrane, and the cytosol can deform the plasma membrane to enable actin-independent endocytosis.
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Affiliation(s)
| | - Sandeep Kumar
- Département de Biochimie, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | | | - Catherine L A Chang
- Department of Chemistry, University of Washington, Seattle, Seattle, WA 98195-1700
| | - Caitlin E Cornell
- Department of Chemistry, University of Washington, Seattle, Seattle, WA 98195-1700
| | - Sarah L Keller
- Department of Chemistry, University of Washington, Seattle, Seattle, WA 98195-1700
| | - Paul François
- Ernest Rutherford Physics Building, McGill University, Montreal, QC H3A 2T8, Canada
| | - Adam G Hendricks
- Department of Bioengineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Allen J Ehrlicher
- Department of Bioengineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130;
| | - Stephen W Michnick
- Département de Biochimie, Université de Montréal, Montréal, QC H3C 3J7, Canada;
- Centre Robert-Cedergren, Bio-Informatique et Génomique, Université de Montréal, Montréal, QC H3C 3J7, Canada
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3
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Nickaeen M, Berro J, Pollard TD, Slepchenko BM. Actin assembly produces sufficient forces for endocytosis in yeast. Mol Biol Cell 2019; 30:2014-2024. [PMID: 31242058 PMCID: PMC6727779 DOI: 10.1091/mbc.e19-01-0059] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We formulated a spatially resolved model to estimate forces exerted by a polymerizing actin meshwork on an invagination of the plasma membrane during endocytosis in yeast cells. The model, which approximates the actin meshwork as a visco-active gel exerting forces on a rigid spherocylinder representing the endocytic invagination, is tightly constrained by experimental data. Simulations of the model produce forces that can overcome resistance of turgor pressure in yeast cells. Strong forces emerge due to the high density of polymerized actin in the vicinity of the invagination and because of entanglement of the meshwork due to its dendritic structure and cross-linking. The model predicts forces orthogonal to the invagination that are consistent with formation of a flask shape, which would diminish the net force due to turgor pressure. Simulations of the model with either two rings of nucleation-promoting factors (NPFs) as in fission yeast or a single ring of NPFs as in budding yeast produce enough force to elongate the invagination against the turgor pressure.
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Affiliation(s)
- Masoud Nickaeen
- Richard D. Berlin Center for Cell Analysis and Modeling, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030
| | - Julien Berro
- Departments of Molecular Biophysics and Biochemistry and of Cell Biology.,Nanobiology Institute, Yale University, New Haven, CT 06520
| | - Thomas D Pollard
- Departments of Molecular Biophysics and Biochemistry and of Cell Biology.,Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Boris M Slepchenko
- Richard D. Berlin Center for Cell Analysis and Modeling, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030
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Lacy MM, Ma R, Ravindra NG, Berro J. Molecular mechanisms of force production in clathrin-mediated endocytosis. FEBS Lett 2018; 592:3586-3605. [PMID: 30006986 PMCID: PMC6231980 DOI: 10.1002/1873-3468.13192] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/21/2018] [Accepted: 07/12/2018] [Indexed: 01/21/2023]
Abstract
During clathrin-mediated endocytosis (CME), a flat patch of membrane is invaginated and pinched off to release a vesicle into the cytoplasm. In yeast CME, over 60 proteins-including a dynamic actin meshwork-self-assemble to deform the plasma membrane. Several models have been proposed for how actin and other molecules produce the forces necessary to overcome the mechanical barriers of membrane tension and turgor pressure, but the precise mechanisms and a full picture of their interplay are still not clear. In this review, we discuss the evidence for these force production models from a quantitative perspective and propose future directions for experimental and theoretical work that could clarify their various contributions.
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Affiliation(s)
- Michael M Lacy
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT, USA
| | - Rui Ma
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
| | - Neal G Ravindra
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
- Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT, USA
| | - Julien Berro
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Nanobiology Institute, Yale University, West Haven, CT, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
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Carlsson AE. Membrane bending by actin polymerization. Curr Opin Cell Biol 2018; 50:1-7. [PMID: 29207306 PMCID: PMC5911415 DOI: 10.1016/j.ceb.2017.11.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 11/20/2017] [Indexed: 01/22/2023]
Abstract
Actin polymerization provides driving force to aid several types of processes that involve pulling the plasma membrane into the cell, including phagocytosis, cellular entry of large viruses, and endocytosis. In endocytosis, actin polymerization is especially important under conditions of high membrane tension or high turgor pressure. Recent modeling efforts have shown how actin polymerization can give rise to a distribution of forces around the endocytic site, and explored how these forces affect the shape dynamics; experiments have revealed the structure of the endocytic machinery in increasing detail, and demonstrated key feedback interactions between actin assembly and membrane curvature. Here we provide a perspective on these findings and suggest avenues for future research.
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Affiliation(s)
- Anders E Carlsson
- Department of Physics, Washington University, One Brookings Drive, Campus Box 1105, St. Louis, MO 63130, United States.
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Abstract
Clathrin-mediated endocytosis in yeast is driven by a protein patch containing close to 100 different types of proteins. Among the proteins are 5000-10000 copies of polymerized actin, and successful endocytosis requires growth of the actin network. Since it is not known exactly how actin network growth drives endocytosis, we calculate the spatial distribution of actin growth required to generate the force that drives the process. First, we establish the force distribution that must be supplied by actin growth, by combining membrane-bending profiles obtained via electron microscopy with established theories of membrane mechanics. Next, we determine the profile of actin growth, using a continuum mechanics approach and an iterative procedure starting with an actin growth profile obtained from a linear analysis. The profile has fairly constant growth outside a central hole of radius 45-50 nm, but very little growth in this hole. This growth profile can reproduce the required forces if the actin shear modulus exceeds 80 kPa, and the growing filaments can exert very large polymerization forces. The growth profile prediction could be tested via electron-microscopy or super-resolution experiments in which the turgor pressure is suddenly turned off.
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Affiliation(s)
- D J Tweten
- Department of Mechanical Engineering, Washington University, St. Louis, Missouri 63130, USA
| | - P V Bayly
- Department of Mechanical Engineering, Washington University, St. Louis, Missouri 63130, USA
| | - A E Carlsson
- Department of Physics, Washington University, St. Louis, Missouri 63130, USA
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