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Delarue M, Brittingham GP, Pfeffer S, Surovtsev IV, Pinglay S, Kennedy KJ, Schaffer M, Gutierrez JI, Sang D, Poterewicz G, Chung JK, Plitzko JM, Groves JT, Jacobs-Wagner C, Engel BD, Holt LJ. mTORC1 Controls Phase Separation and the Biophysical Properties of the Cytoplasm by Tuning Crowding. Cell 2018. [PMID: 29937223 DOI: 10.1016/j.cell.2018.1005.1042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Macromolecular crowding has a profound impact on reaction rates and the physical properties of the cell interior, but the mechanisms that regulate crowding are poorly understood. We developed genetically encoded multimeric nanoparticles (GEMs) to dissect these mechanisms. GEMs are homomultimeric scaffolds fused to a fluorescent protein that self-assemble into bright, stable particles of defined size and shape. By combining tracking of GEMs with genetic and pharmacological approaches, we discovered that the mTORC1 pathway can modulate the effective diffusion coefficient of particles ≥20 nm in diameter more than 2-fold by tuning ribosome concentration, without any discernable effect on the motion of molecules ≤5 nm. This change in ribosome concentration affected phase separation both in vitro and in vivo. Together, these results establish a role for mTORC1 in controlling both the mesoscale biophysical properties of the cytoplasm and biomolecular condensation.
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Affiliation(s)
- M Delarue
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - G P Brittingham
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - S Pfeffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - I V Surovtsev
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Microbial Sciences Institute, Yale West Campus, West Haven, CT 06516, USA
| | - S Pinglay
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - K J Kennedy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 95720, USA
| | - M Schaffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - J I Gutierrez
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 95720, USA
| | - D Sang
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - G Poterewicz
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - J K Chung
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 95720, USA
| | - J M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - J T Groves
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 95720, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - C Jacobs-Wagner
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Microbial Sciences Institute, Yale West Campus, West Haven, CT 06516, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06511, USA
| | - B D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany.
| | - L J Holt
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA.
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Delarue M, Brittingham GP, Pfeffer S, Surovtsev IV, Pinglay S, Kennedy KJ, Schaffer M, Gutierrez JI, Sang D, Poterewicz G, Chung JK, Plitzko JM, Groves JT, Jacobs-Wagner C, Engel BD, Holt LJ. mTORC1 Controls Phase Separation and the Biophysical Properties of the Cytoplasm by Tuning Crowding. Cell 2018; 174:338-349.e20. [PMID: 29937223 PMCID: PMC10080728 DOI: 10.1016/j.cell.2018.05.042] [Citation(s) in RCA: 229] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/26/2018] [Accepted: 05/17/2018] [Indexed: 12/14/2022]
Abstract
Macromolecular crowding has a profound impact on reaction rates and the physical properties of the cell interior, but the mechanisms that regulate crowding are poorly understood. We developed genetically encoded multimeric nanoparticles (GEMs) to dissect these mechanisms. GEMs are homomultimeric scaffolds fused to a fluorescent protein that self-assemble into bright, stable particles of defined size and shape. By combining tracking of GEMs with genetic and pharmacological approaches, we discovered that the mTORC1 pathway can modulate the effective diffusion coefficient of particles ≥20 nm in diameter more than 2-fold by tuning ribosome concentration, without any discernable effect on the motion of molecules ≤5 nm. This change in ribosome concentration affected phase separation both in vitro and in vivo. Together, these results establish a role for mTORC1 in controlling both the mesoscale biophysical properties of the cytoplasm and biomolecular condensation.
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Affiliation(s)
- M Delarue
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - G P Brittingham
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - S Pfeffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - I V Surovtsev
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Microbial Sciences Institute, Yale West Campus, West Haven, CT 06516, USA
| | - S Pinglay
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - K J Kennedy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 95720, USA
| | - M Schaffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - J I Gutierrez
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 95720, USA
| | - D Sang
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - G Poterewicz
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - J K Chung
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 95720, USA
| | - J M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - J T Groves
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 95720, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - C Jacobs-Wagner
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Microbial Sciences Institute, Yale West Campus, West Haven, CT 06516, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06511, USA
| | - B D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany.
| | - L J Holt
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA.
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Walker A, Dunlevy G, Rycroft D, Topley P, Holt LJ, Herbert T, Davies M, Cook F, Holmes S, Jespers L, Herring C. Anti-serum albumin domain antibodies in the development of highly potent, efficacious and long-acting interferon. Protein Eng Des Sel 2010; 23:271-8. [DOI: 10.1093/protein/gzp091] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Holt LJ, Anderson SF. Bilateral occipital lobe stroke with inferior altitudinal defects. Optometry 2000; 71:690-702. [PMID: 11101127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
BACKGROUND Cerebrovascular disease is the most common cause of neurological disability in Western countries. Patients who survive cerebrovascular accidents exclusive to the occipital lobe often have no significant neurological deficits other than visual-field loss. Visual-field defects from occipital lobe stroke typically include congruous homonymous hemianopsias or quadranopsias, with or without macular sparing. CASE REPORT A 61-year-old white man came to us with symptoms of sudden loss of vision and difficulty reading. Visual-field testing revealed a bilateral inferior altitudinal defect with normal optic nerve and fundus appearance in both eyes. On radiological examination, he was found to have had a bioccipital lobe cerebrovascular accident secondary to complete occlusion of the left vertebral artery. An embolic event causing the artery occlusion, in combination with bilaterally compromised cerebellar and posterior cerebral arteries, presumably caused the bilateral stroke. After appropriate medical and neurological consultation, optometric management consisted of maximizing the patient's remaining vision with a prismatic spectacle correction. DISCUSSION/CONCLUSION Patients with infarction exclusive to the occipital lobe typically have no other neurological deficits except visual-field loss and are often easier to manage than patients with infarctions to other areas of the cerebral cortex or multiple infarctions. Visual-field loss from occipital lobe damage can be successfully managed with optical systems and/or visual rehabilitation. Factors related to management include location and extent of visual-field damage, functional visual needs, and both personal and health concerns of the patient. A discussion is presented on cerebrovascular disease, occipital lobe infarction, imaging techniques, and visual rehabilitation.
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Affiliation(s)
- L J Holt
- VA Greater Los Angeles Healthcare System, Sepulveda Ambulatory Care Center and Nursing Home, Fullerton, California, USA
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Abstract
Recombinant antibodies are becoming increasingly important in the field of proteomics. Recent advances include the development of large phage-antibody libraries that contain high-affinity binders to almost any target protein, and new methods for high-throughput selection of antibody-antigen interactions. Coupled with a range of new screening technologies that use high-density antibody arrays to identify differentially expressed proteins, these antibody libraries can be applied to whole proteome analysis.
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Affiliation(s)
- L J Holt
- MRC Laboratory of Molecular Biology and MRC Centre for Protein Engineering, Hills Road, CB2 2QH, Cambridge, UK
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Holt LJ, Büssow K, Walter G, Tomlinson IM. By-passing selection: direct screening for antibody-antigen interactions using protein arrays. Nucleic Acids Res 2000; 28:E72. [PMID: 10908365 PMCID: PMC102691 DOI: 10.1093/nar/28.15.e72] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2000] [Revised: 06/16/2000] [Accepted: 06/16/2000] [Indexed: 01/09/2023] Open
Abstract
We have developed a system to identify highly specific antibody-antigen interactions by protein array screening. This removes the need for selection using animal immunisation or in vitro techniques such as phage or ribosome display. We screened an array of 27 648 human foetal brain proteins with 12 well-expressed antibody fragments that had not previously been exposed to any antigen. Four highly specific antibody-antigen pairs were identified, including three antibodies that bind proteins of unknown function. The target proteins were expressed at a very low copy number on the array, emphasising the unbiased nature of the screen. The specificity and sensitivity of binding demonstrates that this 'naive' screening approach could be applied to the high throughput isolation of specific antibodies against many different targets in the human proteome.
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Affiliation(s)
- L J Holt
- MRC Laboratory of Molecular Biology and MRC Centre for Protein Engineering, Hills Road, Cambridge CB2 2QH, UK
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Abstract
Biochemical surface modification of biomaterials utilizes immobilized biomolecules to induce preferred tissue responses. Although several techniques are available for immobilizing biomolecules on organic substrates, comparatively few are available for use with inorganic materials, such as those used in many orthopedic applications. The present study investigated the stability/elutability of a model enzyme immobilized on Co-Cr-Mo and Ti-6Al-4V alloys using p-nitrophenyl chloroformate (p-NPC). Trypsin-conjugated biomaterials were incubated in cell culture medium at 37 degrees C for up to 96 hr, and the residual immobilized activity was measured. Although all samples initially bound enzymatically active trypsin, significant decreases were observed within the first 2 hr of incubation. Immobilization of trypsin on Co-Cr-Mo treated with 0.65 mg p-NPC/cm2 of nominal surface area gave significantly higher residual activity than on untreated samples at 24-96 hr of incubation and prevented the nearly complete loss of enzymatic activity that was observed with free (not immobilized) enzyme. Derivatization of Ti-6Al-4V with p-NPC was not beneficial to the level of immobilized enzymatic activity after incubation in medium for longer than 6 hr.
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Affiliation(s)
- L J Holt
- Center for Biomedical Engineering University of Kentucky, Lexington 40506, USA
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