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Neininger-Castro AC, Hayes JB, Sanchez ZC, Taneja N, Fenix AM, Moparthi S, Vassilopoulos S, Burnette DT. Independent regulation of Z-lines and M-lines during sarcomere assembly in cardiac myocytes revealed by the automatic image analysis software sarcApp. eLife 2023; 12:RP87065. [PMID: 37921850 PMCID: PMC10624428 DOI: 10.7554/elife.87065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023] Open
Abstract
Sarcomeres are the basic contractile units within cardiac myocytes, and the collective shortening of sarcomeres aligned along myofibrils generates the force driving the heartbeat. The alignment of the individual sarcomeres is important for proper force generation, and misaligned sarcomeres are associated with diseases, including cardiomyopathies and COVID-19. The actin bundling protein, α-actinin-2, localizes to the 'Z-Bodies" of sarcomere precursors and the 'Z-Lines' of sarcomeres, and has been used previously to assess sarcomere assembly and maintenance. Previous measurements of α-actinin-2 organization have been largely accomplished manually, which is time-consuming and has hampered research progress. Here, we introduce sarcApp, an image analysis tool that quantifies several components of the cardiac sarcomere and their alignment in muscle cells and tissue. We first developed sarcApp to utilize deep learning-based segmentation and real space quantification to measure α-actinin-2 structures and determine the organization of both precursors and sarcomeres/myofibrils. We then expanded sarcApp to analyze 'M-Lines' using the localization of myomesin and a protein that connects the Z-Lines to the M-Line (titin). sarcApp produces 33 distinct measurements per cell and 24 per myofibril that allow for precise quantification of changes in sarcomeres, myofibrils, and their precursors. We validated this system with perturbations to sarcomere assembly. We found perturbations that affected Z-Lines and M-Lines differently, suggesting that they may be regulated independently during sarcomere assembly.
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Affiliation(s)
- Abigail C Neininger-Castro
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic SciencesNashvilleUnited States
| | - James B Hayes
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic SciencesNashvilleUnited States
| | - Zachary C Sanchez
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic SciencesNashvilleUnited States
| | - Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic SciencesNashvilleUnited States
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic SciencesNashvilleUnited States
| | - Satish Moparthi
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en MyologieParisFrance
| | - Stéphane Vassilopoulos
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en MyologieParisFrance
| | - Dylan Tyler Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic SciencesNashvilleUnited States
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2
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Neininger-Castro AC, Hayes JB, Sanchez ZC, Taneja N, Fenix AM, Moparthi S, Vassilopoulos S, Burnette DT. Independent regulation of Z-lines and M-lines during sarcomere assembly in cardiac myocytes revealed by the automatic image analysis software sarcApp. bioRxiv 2023:2023.01.11.523681. [PMID: 36711995 PMCID: PMC9882215 DOI: 10.1101/2023.01.11.523681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Sarcomeres are the basic contractile units within cardiac myocytes, and the collective shortening of sarcomeres aligned along myofibrils generates the force driving the heartbeat. The alignment of the individual sarcomeres is important for proper force generation, and misaligned sarcomeres are associated with diseases including cardiomyopathies and COVID-19. The actin bundling protein, α-actinin-2, localizes to the "Z-Bodies" of sarcomere precursors and the "Z-Lines" of sarcomeres, and has been used previously to assess sarcomere assembly and maintenance. Previous measurements of α-actinin-2 organization have been largely accomplished manually, which is time-consuming and has hampered research progress. Here, we introduce sarcApp, an image analysis tool that quantifies several components of the cardiac sarcomere and their alignment in muscle cells and tissue. We first developed sarcApp to utilize deep learning-based segmentation and real space quantification to measure α-actinin-2 structures and determine the organization of both precursors and sarcomeres/myofibrils. We then expanded sarcApp to analyze "M-Lines" using the localization of myomesin and a protein that connects the Z-Lines to the M-Line (titin). sarcApp produces 33 distinct measurements per cell and 24 per myofibril that allow for precise quantification of changes in sarcomeres, myofibrils, and their precursors. We validated this system with perturbations to sarcomere assembly. We found perturbations that affected Z-Lines and M-Lines differently, suggesting that they may be regulated independently during sarcomere assembly.
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Affiliation(s)
- Abigail C. Neininger-Castro
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - James B. Hayes
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - Zachary C. Sanchez
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - Aidan M. Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
| | - Satish Moparthi
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Stéphane Vassilopoulos
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, Paris, France
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine Basic Sciences, Nashville, TN
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Friedman CE, Fayer S, Pendyala S, Chien WM, Loiben A, Tran L, Chao LS, Mckinstry A, Ahmed D, Karbassi E, Fenix AM, Murry CE, Starita LM, Fowler DM, Yang KC. CRaTER enrichment for on-target gene editing enables generation of variant libraries in hiPSCs. J Mol Cell Cardiol 2023; 179:60-71. [PMID: 37019277 PMCID: PMC10208587 DOI: 10.1016/j.yjmcc.2023.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/14/2023] [Accepted: 03/29/2023] [Indexed: 04/07/2023]
Abstract
Standard transgenic cell line generation requires screening 100-1000s of colonies to isolate correctly edited cells. We describe CRISPRa On-Target Editing Retrieval (CRaTER) which enriches for cells with on-target knock-in of a cDNA-fluorescent reporter transgene by transient activation of the targeted locus followed by flow sorting to recover edited cells. We show CRaTER recovers rare cells with heterozygous, biallelic-editing of the transcriptionally-inactive MYH7 locus in human induced pluripotent stem cells (hiPSCs), enriching on average 25-fold compared to standard antibiotic selection. We leveraged CRaTER to enrich for heterozygous knock-in of a library of variants in MYH7, a gene in which missense mutations cause cardiomyopathies, and recovered hiPSCs with 113 different variants. We differentiated these hiPSCs to cardiomyocytes and show MHC-β fusion proteins can localize as expected. Additionally, single-cell contractility analyses revealed cardiomyocytes with a pathogenic, hypertrophic cardiomyopathy-associated MYH7 variant exhibit salient HCM physiology relative to isogenic controls. Thus, CRaTER substantially reduces screening required for isolation of gene-edited cells, enabling generation of functional transgenic cell lines at unprecedented scale.
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Affiliation(s)
- Clayton E Friedman
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA
| | - Shawn Fayer
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Sriram Pendyala
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Wei-Ming Chien
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA; Cardiology/Hospital Specialty Medicine, VA Puget Sound HCS, Seattle, WA 98108, USA
| | - Alexander Loiben
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA
| | - Linda Tran
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA
| | - Leslie S Chao
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA
| | - Ashley Mckinstry
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA
| | - Dania Ahmed
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA
| | - Elaheh Karbassi
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98109, USA
| | - Aidan M Fenix
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98109, USA
| | - Charles E Murry
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98109, USA; Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Lea M Starita
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Brotman Baty Institute for Precision Medicine, Seattle, WA 98195, USA
| | - Douglas M Fowler
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Brotman Baty Institute for Precision Medicine, Seattle, WA 98195, USA
| | - Kai-Chun Yang
- Institute for Stem Cell and Regenerative Medicine, University of Washington, School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA; Cardiology/Hospital Specialty Medicine, VA Puget Sound HCS, Seattle, WA 98108, USA.
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4
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Marchiano S, Nakamura K, Reinecke H, Neidig L, Lai M, Kadota S, Perbellini F, Yang X, Klaiman JM, Blakely LP, Karbassi E, Fields PA, Fenix AM, Beussman KM, Jayabalu A, Kalucki FA, Potter JC, Futakuchi-Tsuchida A, Weber GJ, Dupras S, Tsuchida H, Pabon L, Wang L, Knollmann BC, Kattman S, Thies RS, Sniadecki N, MacLellan WR, Bertero A, Murry CE. Gene editing to prevent ventricular arrhythmias associated with cardiomyocyte cell therapy. Cell Stem Cell 2023; 30:741. [PMID: 37146587 PMCID: PMC10286102 DOI: 10.1016/j.stem.2023.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
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5
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Marchiano S, Nakamura K, Reinecke H, Neidig L, Lai M, Kadota S, Perbellini F, Yang X, Klaiman JM, Blakely LP, Karbassi E, Fields PA, Fenix AM, Beussman KM, Jayabalu A, Kalucki FA, Potter JC, Futakuchi-Tsuchida A, Weber GJ, Dupras S, Tsuchida H, Pabon L, Wang L, Knollmann BC, Kattman S, Thies RS, Sniadecki N, MacLellan WR, Bertero A, Murry CE. Gene editing to prevent ventricular arrhythmias associated with cardiomyocyte cell therapy. Cell Stem Cell 2023; 30:396-414.e9. [PMID: 37028405 PMCID: PMC10283080 DOI: 10.1016/j.stem.2023.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/03/2023] [Accepted: 03/16/2023] [Indexed: 04/08/2023]
Abstract
Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) offer a promising cell-based therapy for myocardial infarction. However, the presence of transitory ventricular arrhythmias, termed engraftment arrhythmias (EAs), hampers clinical applications. We hypothesized that EA results from pacemaker-like activity of hPSC-CMs associated with their developmental immaturity. We characterized ion channel expression patterns during maturation of transplanted hPSC-CMs and used pharmacology and genome editing to identify those responsible for automaticity in vitro. Multiple engineered cell lines were then transplanted in vivo into uninjured porcine hearts. Abolishing depolarization-associated genes HCN4, CACNA1H, and SLC8A1, along with overexpressing hyperpolarization-associated KCNJ2, creates hPSC-CMs that lack automaticity but contract when externally stimulated. When transplanted in vivo, these cells engrafted and coupled electromechanically with host cardiomyocytes without causing sustained EAs. This study supports the hypothesis that the immature electrophysiological prolife of hPSC-CMs mechanistically underlies EA. Thus, targeting automaticity should improve the safety profile of hPSC-CMs for cardiac remuscularization.
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Affiliation(s)
- Silvia Marchiano
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Kenta Nakamura
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Hans Reinecke
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Lauren Neidig
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Comparative Medicine, University of Washington, Seattle, WA 98195, USA
| | | | - Shin Kadota
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Department of Regenerative Science and Medicine, Shinshu University, Matsumoto 390-8621, Japan
| | | | - Xiulan Yang
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Jordan M Klaiman
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Leslie P Blakely
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Elaheh Karbassi
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Paul A Fields
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Adaptive Biotechnologies, Seattle, WA 98102, USA
| | - Aidan M Fenix
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Kevin M Beussman
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Mechanical Engineering, University of Washington, 3720 15(th) Avenue NE, Seattle, WA 98105, USA
| | - Anu Jayabalu
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Faith A Kalucki
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Jennifer C Potter
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Akiko Futakuchi-Tsuchida
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Gerhard J Weber
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Sarah Dupras
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Hiroshi Tsuchida
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Lil Pabon
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Lili Wang
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Björn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Steven Kattman
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - R Scott Thies
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA
| | - Nathan Sniadecki
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Department of Mechanical Engineering, University of Washington, 3720 15(th) Avenue NE, Seattle, WA 98105, USA; Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - W Robb MacLellan
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Alessandro Bertero
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA
| | - Charles E Murry
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Brotman Building Room 453, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA 98195, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Sana Biotechnology, Seattle, WA 98102, USA; Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
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6
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Friedman CE, Fayer S, Pendyala S, Chien WM, Tran L, Chao L, Mckinstry A, Karbassi E, Fenix AM, Loiben A, Murry CE, Starita LM, Fowler DM, Yang KC. CRaTER enrichment for on-target gene-editing enables generation of variant libraries in hiPSCs. bioRxiv 2023:2023.01.25.525582. [PMID: 36747685 PMCID: PMC9900876 DOI: 10.1101/2023.01.25.525582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
Standard transgenic cell line generation requires screening 100-1000s of colonies to isolate correctly edited cells. We describe CR ISPR a On- T arget E diting R etrieval (CRaTER) which enriches for cells with on-target knock-in of a cDNA-fluorescent reporter transgene by transient activation of the targeted locus followed by flow sorting to recover edited cells. We show CRaTER recovers rare cells with heterozygous, biallelic-editing of the transcriptionally-inactive MYH7 locus in human induced pluripotent stem cells (hiPSCs), enriching on average 25-fold compared to standard antibiotic selection. We leveraged CRaTER to enrich for heterozygous knock-in of a library of single nucleotide variants (SNVs) in MYH7 , a gene in which missense mutations cause cardiomyopathies, and recovered hiPSCs with 113 different MYH7 SNVs. We differentiated these hiPSCs to cardiomyocytes and show MYH7 fusion proteins can localize as expected. Thus, CRaTER substantially reduces screening required for isolation of gene-edited cells, enabling generation of transgenic cell lines at unprecedented scale.
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7
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Fenix AM, Miyaoka Y, Bertero A, Blue SM, Spindler MJ, Tan KKB, Perez-Bermejo JA, Chan AH, Mayerl SJ, Nguyen TD, Russell CR, Lizarraga PP, Truong A, So PL, Kulkarni A, Chetal K, Sathe S, Sniadecki NJ, Yeo GW, Murry CE, Conklin BR, Salomonis N. Gain-of-function cardiomyopathic mutations in RBM20 rewire splicing regulation and re-distribute ribonucleoprotein granules within processing bodies. Nat Commun 2021; 12:6324. [PMID: 34732726 PMCID: PMC8566601 DOI: 10.1038/s41467-021-26623-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 09/22/2021] [Indexed: 12/16/2022] Open
Abstract
Mutations in the cardiac splicing factor RBM20 lead to malignant dilated cardiomyopathy (DCM). To understand the mechanism of RBM20-associated DCM, we engineered isogenic iPSCs with DCM-associated missense mutations in RBM20 as well as RBM20 knockout (KO) iPSCs. iPSC-derived engineered heart tissues made from these cell lines recapitulate contractile dysfunction of RBM20-associated DCM and reveal greater dysfunction with missense mutations than KO. Analysis of RBM20 RNA binding by eCLIP reveals a gain-of-function preference of mutant RBM20 for 3' UTR sequences that are shared with amyotrophic lateral sclerosis (ALS) and processing-body associated RNA binding proteins (FUS, DDX6). Deep RNA sequencing reveals that the RBM20 R636S mutant has unique gene, splicing, polyadenylation and circular RNA defects that differ from RBM20 KO. Super-resolution microscopy verifies that mutant RBM20 maintains very limited nuclear localization potential; rather, the mutant protein associates with cytoplasmic processing bodies (DDX6) under basal conditions, and with stress granules (G3BP1) following acute stress. Taken together, our results highlight a pathogenic mechanism in cardiac disease through splicing-dependent and -independent pathways.
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Affiliation(s)
- Aidan M Fenix
- Department of Laboratory Medicine and Pathology, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
- Center for Cardiovascular Biology, University of Washington, 850 Republican Street, Brotman Building, Seattle, WA, 98109, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Seattle, WA, 98109, USA
| | - Yuichiro Miyaoka
- Regenerative Medicine Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, 156-8506, Japan
- Gladstone Institutes, 1650 Owens St, San Francisco, CA, 94158, USA
| | - Alessandro Bertero
- Department of Laboratory Medicine and Pathology, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
- Center for Cardiovascular Biology, University of Washington, 850 Republican Street, Brotman Building, Seattle, WA, 98109, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Seattle, WA, 98109, USA
| | - Steven M Blue
- Department of Cellular and Molecular Medicine, Stem Cell Program, and Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | | | - Kenneth K B Tan
- Gladstone Institutes, 1650 Owens St, San Francisco, CA, 94158, USA
| | | | - Amanda H Chan
- Gladstone Institutes, 1650 Owens St, San Francisco, CA, 94158, USA
| | - Steven J Mayerl
- Gladstone Institutes, 1650 Owens St, San Francisco, CA, 94158, USA
| | - Trieu D Nguyen
- Gladstone Institutes, 1650 Owens St, San Francisco, CA, 94158, USA
| | | | | | - Annie Truong
- Gladstone Institutes, 1650 Owens St, San Francisco, CA, 94158, USA
| | - Po-Lin So
- Gladstone Institutes, 1650 Owens St, San Francisco, CA, 94158, USA
| | - Aishwarya Kulkarni
- Department of Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, 45221, USA
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Kashish Chetal
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Shashank Sathe
- Department of Cellular and Molecular Medicine, Stem Cell Program, and Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Nathan J Sniadecki
- Department of Laboratory Medicine and Pathology, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
- Center for Cardiovascular Biology, University of Washington, 850 Republican Street, Brotman Building, Seattle, WA, 98109, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Seattle, WA, 98109, USA
- Department of Mechanical Engineering, University of Washington, 3720 15th Avenue NE, Seattle, WA, 98105, USA
- Department of Bioengineering, University of Washington, 3720 15th Avenue NE, Seattle, WA, 98105, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, Stem Cell Program, and Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Charles E Murry
- Department of Laboratory Medicine and Pathology, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.
- Center for Cardiovascular Biology, University of Washington, 850 Republican Street, Brotman Building, Seattle, WA, 98109, USA.
- Institute for Stem Cell and Regenerative Medicine, University of Washington, 850 Republican Street, Seattle, WA, 98109, USA.
- Department of Bioengineering, University of Washington, 3720 15th Avenue NE, Seattle, WA, 98105, USA.
- Department of Medicine/Cardiology, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.
- Sana Biotechnology, 188 E Blaine Street, Seattle, WA, 98102, USA.
| | - Bruce R Conklin
- Gladstone Institutes, 1650 Owens St, San Francisco, CA, 94158, USA.
- Department of Medicine, Cellular and Molecular Pharmacology, and Ophthalmology, University of California San Francisco, San Francisco, CA, 94158, USA.
| | - Nathan Salomonis
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45229, USA.
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8
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Taneja N, Bersi MR, Baillargeon SM, Fenix AM, Cooper JA, Ohi R, Gama V, Merryman WD, Burnette DT. Precise Tuning of Cortical Contractility Regulates Cell Shape during Cytokinesis. Cell Rep 2021; 31:107477. [PMID: 32268086 DOI: 10.1016/j.celrep.2020.03.041] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/27/2020] [Accepted: 03/13/2020] [Indexed: 01/30/2023] Open
Abstract
The mechanical properties of the actin cortex regulate shape changes during cell division, cell migration, and tissue morphogenesis. We show that modulation of myosin II (MII) filament composition allows tuning of surface tension at the cortex to maintain cell shape during cytokinesis. Our results reveal that MIIA generates cortex tension, while MIIB acts as a stabilizing motor and its inclusion in MII hetero-filaments reduces cortex tension. Tension generation by MIIA drives faster cleavage furrow ingression and bleb formation. We also show distinct roles for the motor and tail domains of MIIB in maintaining cytokinetic fidelity. Maintenance of cortical stability by the motor domain of MIIB safeguards against shape instability-induced chromosome missegregation, while its tail domain mediates cortical localization at the terminal stages of cytokinesis to mediate cell abscission. Because most non-muscle contractile systems are cortical, this tuning mechanism will likely be applicable to numerous processes driven by myosin-II contractility.
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Affiliation(s)
- Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Matthew R Bersi
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
| | - Sophie M Baillargeon
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - James A Cooper
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Ryoma Ohi
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vivian Gama
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - W David Merryman
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.
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9
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Wan KY, Hürlimann SK, Fenix AM, McGillivary RM, Makushok T, Burns E, Sheung JY, Marshall WF. Reorganization of complex ciliary flows around regenerating Stentor coeruleus. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190167. [PMID: 31884915 PMCID: PMC7017328 DOI: 10.1098/rstb.2019.0167] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The phenomenon of ciliary coordination has garnered increasing attention in recent decades and multiple theories have been proposed to explain its occurrence in different biological systems. While hydrodynamic interactions are thought to dictate the large-scale coordinated activity of epithelial cilia for fluid transport, it is rather basal coupling that accounts for synchronous swimming gaits in model microeukaryotes such as Chlamydomonas. Unicellular ciliates present a fascinating yet understudied context in which coordination is found to persist in ciliary arrays positioned across millimetre scales on the same cell. Here, we focus on the ciliate Stentor coeruleus, chosen for its large size, complex ciliary organization, and capacity for cellular regeneration. These large protists exhibit ciliary differentiation between cortical rows of short body cilia used for swimming, and an anterior ring of longer, fused cilia called the membranellar band (MB). The oral cilia in the MB beat metachronously to produce strong feeding currents. Remarkably, upon injury, the MB can be shed and regenerated de novo. Here, we follow and track this developmental sequence in its entirety to elucidate the emergence of coordinated ciliary beating: from band formation, elongation, curling and final migration towards the cell anterior. We reveal a complex interplay between hydrodynamics and ciliary restructuring in Stentor, and highlight for the first time the importance of a ring-like topology for achieving long-range metachronism in ciliated structures. This article is part of the Theo Murphy meeting issue ‘Unity and diversity of cilia in locomotion and transport’.
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Affiliation(s)
- Kirsty Y Wan
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.,Marine Biological Laboratory, Physiology Course, Woods Hole, MA 02543, USA
| | - Sylvia K Hürlimann
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.,Marine Biological Laboratory, Physiology Course, Woods Hole, MA 02543, USA
| | - Aidan M Fenix
- Department of Pathology, University of Washington, WA 98109, USA.,Center for Cardiovascular Biology, University of Washington, WA 98109, USA.,Marine Biological Laboratory, Physiology Course, Woods Hole, MA 02543, USA
| | - Rebecca M McGillivary
- Department of Biochemistry and Biophysics, UCSF, San Francisco, CA 94143, USA.,Marine Biological Laboratory, Physiology Course, Woods Hole, MA 02543, USA
| | - Tatyana Makushok
- Department of Biochemistry and Biophysics, UCSF, San Francisco, CA 94143, USA.,Marine Biological Laboratory, Physiology Course, Woods Hole, MA 02543, USA
| | - Evan Burns
- Department of Biology, Vassar College, NY 12604, USA.,Marine Biological Laboratory, Whitman Center, Woods Hole, MA 02543, USA
| | - Janet Y Sheung
- Department of Physics and Astronomy, Vassar College, NY 12604, USA.,Marine Biological Laboratory, Whitman Center, Woods Hole, MA 02543, USA
| | - Wallace F Marshall
- Department of Biochemistry and Biophysics, UCSF, San Francisco, CA 94143, USA.,Marine Biological Laboratory, Physiology Course, Woods Hole, MA 02543, USA
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10
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Burnette DT, Fenix AM, Neininger AC, Taneja N, Hyde K, Visetsouk MR, Garde R, Liu B, Nixon BR, Manalo AE, Becker JR, Crawley SW, Bader DM, Tyska MJ, Liu Q, Gutzman JH. Abstract 901: Muscle-specific Stress Fibers Give Rise to Sarcomeres in Cardiomyocytes. Circ Res 2019. [DOI: 10.1161/res.125.suppl_1.901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The sarcomere is the contractile unit that drives muscle contraction. Despite its importance, little is understood about how a disordered acto-myosin distribution converts into an ordered contractile array during sarcomere assembly. Here, we take advantage of a sarcomere assembly assay we developed using human induced pluripotent stem cell derived cardiomycytes to image the formation of sarcomeres, using live-cell high resolution microscopy. Our data show that a population of muscle specific stress fibers (MSFs) are essential sarcomere precursors. Interestingly, MSFs are formed at the leading edge of cells, undergo retrograde flow, and transition into sarcomere-containing myofibrils on the dorsal surface of cardiomyocytes. This is in direct contradiction to a recent report claiming sarcomeres are formed from adhesions on the ventral surface of cardiomyocytes. We have been able to recapitulate this other group's published experiments and definitively show that sarcomeres are not forming from the bottom of the cells or streaming out of adhesions. Instead, our 3D microscopy data shows that this group was imaging sarcomeres which were already formed on the dorsal surface and were traveling to the ventral surface of the cells. After this important clarification, we used our assay to show that the transition of MSFs to sarcomere-containing myofibrils requires formin-mediated actin polymerization and the non-muscle myosin IIA and myosin IIB. We conclude that sarcomeres form by a "templating" mechanism similar to that originally postulated by Howard Holtzer >30 years ago. Furthermore, our data show short β cardiac myosin II filaments are themselves templated by "non-muscle" myosin II filaments. Subsequently, the short β cardiac myosin II filaments grow to form ~1.5 μm long filaments that then “stitch” together to form the stack of filaments at the core of the sarcomere (i.e., the A-band). Taken together, our data show that the differentiation of cardiomyocytes from stem cells is a powerful tool for dissecting the mechanisms controlling sarcomere assembly.
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Affiliation(s)
| | | | | | | | | | | | - Ryan Garde
- Vanderbilt Sch of Medicine, Nashville, TN
| | | | | | | | | | | | | | | | - Qi Liu
- Vanderbilt Sch of Medicine, Nashville, TN
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11
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Howard AM, LaFever KS, Fenix AM, Scurrah CR, Lau KS, Burnette DT, Bhave G, Ferrell N, Page-McCaw A. DSS-induced damage to basement membranes is repaired by matrix replacement and crosslinking. J Cell Sci 2019; 132:jcs.226860. [PMID: 30837285 DOI: 10.1242/jcs.226860] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [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: 10/22/2018] [Accepted: 02/22/2019] [Indexed: 12/12/2022] Open
Abstract
Basement membranes are an ancient form of animal extracellular matrix. As important structural and functional components of tissues, basement membranes are subject to environmental damage and must be repaired while maintaining functions. Little is known about how basement membranes get repaired. This paucity stems from a lack of suitable in vivo models for analyzing such repair. Here, we show that dextran sodium sulfate (DSS) directly damages the gut basement membrane when fed to adult Drosophila DSS becomes incorporated into the basement membrane, promoting its expansion while decreasing its stiffness, which causes morphological changes to the underlying muscles. Remarkably, two days after withdrawal of DSS, the basement membrane is repaired by all measures of analysis. We used this new damage model to determine that repair requires collagen crosslinking and replacement of damaged components. Genetic and biochemical evidence indicates that crosslinking is required to stabilize the newly incorporated repaired Collagen IV rather than to stabilize the damaged Collagen IV. These results suggest that basement membranes are surprisingly dynamic.
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Affiliation(s)
- Angela M Howard
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kimberly S LaFever
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA
| | - Cherie' R Scurrah
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.,Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Ken S Lau
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.,Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Gautam Bhave
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA.,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Nicholas Ferrell
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235-1631, USA
| | - Andrea Page-McCaw
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7935, USA .,Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Program in Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.,Program in Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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12
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Jeppesen DK, Fenix AM, Franklin JL, Higginbotham JN, Zhang Q, Zimmerman LJ, Liebler DC, Ping J, Liu Q, Evans R, Fissell WH, Patton JG, Rome LH, Burnette DT, Coffey RJ. Reassessment of Exosome Composition. Cell 2019; 177:428-445.e18. [PMID: 30951670 PMCID: PMC6664447 DOI: 10.1016/j.cell.2019.02.029] [Citation(s) in RCA: 1567] [Impact Index Per Article: 313.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/08/2018] [Accepted: 02/15/2019] [Indexed: 12/13/2022]
Abstract
The heterogeneity of small extracellular vesicles and presence of non-vesicular extracellular matter have led to debate about contents and functional properties of exosomes. Here, we employ high-resolution density gradient fractionation and direct immunoaffinity capture to precisely characterize the RNA, DNA, and protein constituents of exosomes and other non-vesicle material. Extracellular RNA, RNA-binding proteins, and other cellular proteins are differentially expressed in exosomes and non-vesicle compartments. Argonaute 1-4, glycolytic enzymes, and cytoskeletal proteins were not detected in exosomes. We identify annexin A1 as a specific marker for microvesicles that are shed directly from the plasma membrane. We further show that small extracellular vesicles are not vehicles of active DNA release. Instead, we propose a new model for active secretion of extracellular DNA through an autophagy- and multivesicular-endosome-dependent but exosome-independent mechanism. This study demonstrates the need for a reassessment of exosome composition and offers a framework for a clearer understanding of extracellular vesicle heterogeneity.
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Affiliation(s)
- Dennis K Jeppesen
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Jeffrey L Franklin
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Veterans Affairs Medical Center, Nashville, TN 37232, USA
| | - James N Higginbotham
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Qin Zhang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Lisa J Zimmerman
- Jim Ayers Institute for Precancer Detection and Diagnosis, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Daniel C Liebler
- Jim Ayers Institute for Precancer Detection and Diagnosis, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jie Ping
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Qi Liu
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel Evans
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - William H Fissell
- Division of Nephrology and Hypertension, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - James G Patton
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Leonard H Rome
- Department of Biological Chemistry, David Geffen School of Medicine and the California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Robert J Coffey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Veterans Affairs Medical Center, Nashville, TN 37232, USA.
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13
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Fenix AM, Burnette DT. Cover Image, Volume 75, Issue 12. Cytoskeleton (Hoboken) 2019. [DOI: 10.1002/cm.21512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Aidan M. Fenix
- Department of Cell and Developmental Biology Vanderbilt University School of Medicine Nashville Tennessee
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology Vanderbilt University School of Medicine Nashville Tennessee
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14
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Jiu Y, Kumari R, Fenix AM, Schaible N, Liu X, Varjosalo M, Krishnan R, Burnette DT, Lappalainen P. Myosin-18B Promotes the Assembly of Myosin II Stacks for Maturation of Contractile Actomyosin Bundles. Curr Biol 2018; 29:81-92.e5. [PMID: 30581023 DOI: 10.1016/j.cub.2018.11.045] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [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: 06/08/2018] [Revised: 10/12/2018] [Accepted: 11/16/2018] [Indexed: 10/27/2022]
Abstract
Cell adhesion, morphogenesis, mechanosensing, and muscle contraction rely on contractile actomyosin bundles, where the force is produced through sliding of bipolar myosin II filaments along actin filaments. The assembly of contractile actomyosin bundles involves registered alignment of myosin II filaments and their subsequent fusion into large stacks. However, mechanisms underlying the assembly of myosin II stacks and their physiological functions have remained elusive. Here, we identified myosin-18B, an unconventional myosin, as a stable component of contractile stress fibers. Myosin-18B co-localized with myosin II motor domains in stress fibers and was enriched at the ends of myosin II stacks. Importantly, myosin-18B deletion resulted in drastic defects in the concatenation and persistent association of myosin II filaments with each other and thus led to severely impaired assembly of myosin II stacks. Consequently, lack of myosin-18B resulted in defective maturation of actomyosin bundles from their precursors in osteosarcoma cells. Moreover, myosin-18B knockout cells displayed abnormal morphogenesis, migration, and ability to exert forces to the environment. These results reveal a critical role for myosin-18B in myosin II stack assembly and provide evidence that myosin II stacks are important for a variety of vital processes in cells.
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Affiliation(s)
- Yaming Jiu
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland; CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Reena Kumari
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Niccole Schaible
- Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Xiaonan Liu
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland
| | - Ramaswamy Krishnan
- Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Pekka Lappalainen
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland.
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15
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Fenix AM, Neininger AC, Taneja N, Hyde K, Visetsouk MR, Garde RJ, Liu B, Nixon BR, Manalo AE, Becker JR, Crawley SW, Bader DM, Tyska MJ, Liu Q, Gutzman JH, Burnette DT. Muscle-specific stress fibers give rise to sarcomeres in cardiomyocytes. eLife 2018; 7:42144. [PMID: 30540249 PMCID: PMC6307863 DOI: 10.7554/elife.42144] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/11/2018] [Indexed: 11/13/2022] Open
Abstract
The sarcomere is the contractile unit within cardiomyocytes driving heart muscle contraction. We sought to test the mechanisms regulating actin and myosin filament assembly during sarcomere formation. Therefore, we developed an assay using human cardiomyocytes to monitor sarcomere assembly. We report a population of muscle stress fibers, similar to actin arcs in non-muscle cells, which are essential sarcomere precursors. We show sarcomeric actin filaments arise directly from muscle stress fibers. This requires formins (e.g., FHOD3), non-muscle myosin IIA and non-muscle myosin IIB. Furthermore, we show short cardiac myosin II filaments grow to form ~1.5 μm long filaments that then 'stitch' together to form the stack of filaments at the core of the sarcomere (i.e., the A-band). A-band assembly is dependent on the proper organization of actin filaments and, as such, is also dependent on FHOD3 and myosin IIB. We use this experimental paradigm to present evidence for a unifying model of sarcomere assembly.
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Affiliation(s)
- Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Abigail C Neininger
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Karren Hyde
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Mike R Visetsouk
- Department of Biological Sciences, Cell and Molecular Biology, University of Wisconsin Milwaukee, Milwaukee, United States
| | - Ryan J Garde
- Department of Biological Sciences, Cell and Molecular Biology, University of Wisconsin Milwaukee, Milwaukee, United States
| | - Baohong Liu
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
| | - Benjamin R Nixon
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States
| | - Annabelle E Manalo
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Jason R Becker
- Department of Medicine, Vanderbilt University Medical Center, Nashville, United States
| | - Scott W Crawley
- Department of Biological Sciences, The University of Toledo, Toledo, United States
| | - David M Bader
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Qi Liu
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
| | - Jennifer H Gutzman
- Department of Biological Sciences, Cell and Molecular Biology, University of Wisconsin Milwaukee, Milwaukee, United States
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
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16
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Fenix AM, Burnette DT. Assembly of myosin II filament arrays: Network Contraction versus Expansion. Cytoskeleton (Hoboken) 2018; 75:545-549. [PMID: 30126071 DOI: 10.1002/cm.21487] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [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: 06/06/2018] [Revised: 07/31/2018] [Accepted: 08/13/2018] [Indexed: 12/18/2022]
Abstract
How cellular contractile systems assemble has fascinated scientists for generations. The major molecule responsible for cellular force generation is the molecular motor, non-muscle myosin II (NMII). NMII molecules are organized into single myosin filaments and larger arrays of filaments called NMII stacks, which are capable of generating increasing amounts of force. The textbook model of NMII stack assembly is the Network Contraction Model, where ensembles of distinct NMII filaments condense into a NMII stack by pulling on actin filaments. While this model has been widely accepted for ~20 years, it has been difficult to test inside cells due to the small size of NMII filaments. Recently, interest in how NMII stacks form has been reinvigorated by the advent of super-resolution microscopy techniques which have afforded unprecedented resolution of NMII filaments inside cells. A number of recent publications using these techniques have called into question key aspects of the Network Contraction Model, and our understanding of how NMII stacks assemble.
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Affiliation(s)
- Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
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17
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Lehtimäki JI, Fenix AM, Kotila TM, Balistreri G, Paavolainen L, Varjosalo M, Burnette DT, Lappalainen P. UNC-45a promotes myosin folding and stress fiber assembly. J Cell Biol 2017; 216:4053-4072. [PMID: 29055011 PMCID: PMC5716280 DOI: 10.1083/jcb.201703107] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 08/28/2017] [Accepted: 09/19/2017] [Indexed: 12/15/2022] Open
Abstract
Contractile actomyosin bundles, stress fibers, are crucial for adhesion, morphogenesis, and mechanosensing in nonmuscle cells. However, the mechanisms by which nonmuscle myosin II (NM-II) is recruited to those structures and assembled into functional bipolar filaments have remained elusive. We report that UNC-45a is a dynamic component of actin stress fibers and functions as a myosin chaperone in vivo. UNC-45a knockout cells display severe defects in stress fiber assembly and consequent abnormalities in cell morphogenesis, polarity, and migration. Experiments combining structured-illumination microscopy, gradient centrifugation, and proteasome inhibition approaches revealed that a large fraction of NM-II and myosin-1c molecules fail to fold in the absence of UNC-45a. The remaining properly folded NM-II molecules display defects in forming functional bipolar filaments. The C-terminal UNC-45/Cro1/She4p domain of UNC-45a is critical for NM-II folding, whereas the N-terminal tetratricopeptide repeat domain contributes to the assembly of functional stress fibers. Thus, UNC-45a promotes generation of contractile actomyosin bundles through synchronized NM-II folding and filament-assembly activities.
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Affiliation(s)
| | - Aidan M Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Tommi M Kotila
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Giuseppe Balistreri
- Department of Biosciences, Division of General Microbiology, University of Helsinki, Helsinki, Finland
| | - Lassi Paavolainen
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Dylan T Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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18
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Balikov DA, Crowder SW, Boire TC, Lee JB, Gupta MK, Fenix AM, Lewis HN, Ambrose CM, Short PA, Kim CS, Burnette DT, Reilly MA, Murthy NS, Kang ML, Kim WS, Sung HJ. Tunable Surface Repellency Maintains Stemness and Redox Capacity of Human Mesenchymal Stem Cells. ACS Appl Mater Interfaces 2017; 9:22994-23006. [PMID: 28621931 PMCID: PMC5687519 DOI: 10.1021/acsami.7b06103] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Human bone marrow derived mesenchymal stem cells (hMSCs) hold great promise for regenerative medicine due to their multipotent differentiation capacity and immunomodulatory capabilities. Substantial research has elucidated mechanisms by which extracellular cues regulate hMSC fate decisions, but considerably less work has addressed how material properties can be leveraged to maintain undifferentiated stem cells. Here, we show that synthetic culture substrates designed to exhibit moderate cell-repellency promote high stemness and low oxidative stress-two indicators of naïve, healthy stem cells-in commercial and patient-derived hMSCs. Furthermore, the material-mediated effect on cell behavior can be tuned by altering the molar percentage (mol %) and/or chain length of poly(ethylene glycol) (PEG), the repellant block linked to hydrophobic poly(ε-caprolactone) (PCL) in the copolymer backbone. Nano- and angstrom-scale characterization of the cell-material interface reveals that PEG interrupts the adhesive PCL domains in a chain-length-dependent manner; this prevents hMSCs from forming mature focal adhesions and subsequently promotes cell-cell adhesions that require connexin-43. This study is the first to demonstrate that intrinsic properties of synthetic materials can be tuned to regulate the stemness and redox capacity of hMSCs and provides new insight for designing highly scalable, programmable culture platforms for clinical translation.
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Affiliation(s)
- Daniel A. Balikov
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Spencer W. Crowder
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Timothy C. Boire
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jung Bok Lee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Mukesh K. Gupta
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Aidan M. Fenix
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Holley N. Lewis
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Caitlyn M. Ambrose
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Philip A. Short
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Chang Soo Kim
- Department of Materials Science and Engineering, University of Wisconsin, Milwaukee, Wisconsin 53211, United States
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Matthew A. Reilly
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - N. Sanjeeva Murthy
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Mi-Lan Kang
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul 120-752, Republic of Korea
| | - Won Shik Kim
- Department of Otorhinolaryngology, College of Medicine, Yonsei University, Seoul 120-752, Republic of Korea
| | - Hak-Joon Sung
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
- Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul 120-752, Republic of Korea
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19
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Taneja N, Fenix AM, Rathbun L, Millis BA, Tyska MJ, Hehnly H, Burnette DT. Focal adhesions control cleavage furrow shape and spindle tilt during mitosis. Sci Rep 2016; 6:29846. [PMID: 27432211 PMCID: PMC4949487 DOI: 10.1038/srep29846] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 06/24/2016] [Indexed: 01/01/2023] Open
Abstract
The geometry of the cleavage furrow during mitosis is often asymmetric in vivo and plays a critical role in stem cell differentiation and the relative positioning of daughter cells during development. Early observations of adhesive cell lines revealed asymmetry in the shape of the cleavage furrow, where the bottom (i.e., substrate attached side) of the cleavage furrow ingressed less than the top (i.e., unattached side). This data suggested substrate attachment could be regulating furrow ingression. Here we report a population of mitotic focal adhesions (FAs) controls the symmetry of the cleavage furrow. In single HeLa cells, stronger adhesion to the substrate directed less ingression from the bottom of the cell through a pathway including paxillin, focal adhesion kinase (FAK) and vinculin. Cell-cell contacts also direct ingression of the cleavage furrow in coordination with FAs in epithelial cells-MDCK-within monolayers and polarized cysts. In addition, mitotic FAs established 3D orientation of the mitotic spindle and the relative positioning of mother and daughter centrosomes. Therefore, our data reveals mitotic FAs as a key link between mitotic cell shape and spindle orientation, and may have important implications in our understanding stem cell homeostasis and tumorigenesis.
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Affiliation(s)
- Nilay Taneja
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Aidan M. Fenix
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lindsay Rathbun
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Bryan A. Millis
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Heidi Hehnly
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Dylan T. Burnette
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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20
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Fenix AM, Taneja N, Buttler CA, Lewis J, Van Engelenburg SB, Ohi R, Burnette DT. Expansion and concatenation of non-muscle myosin IIA filaments drive cellular contractile system formation during interphase and mitosis. Mol Biol Cell 2016; 27:mbc.E15-10-0725. [PMID: 26960797 PMCID: PMC4850034 DOI: 10.1091/mbc.e15-10-0725] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/25/2016] [Accepted: 03/01/2016] [Indexed: 11/19/2022] Open
Abstract
Cell movement and cytokinesis are facilitated by contractile forces generated by the molecular motor, non-muscle myosin II (NMII). NMII molecules form a filament (NMII-F) through interactions of their C-terminal rod domains, positioning groups of N-terminal motor domains on opposite sides. The NMII motors then bind and pull actin filaments toward the NMII-F, thus driving contraction. Inside of crawling cells, NMIIA-Fs form large macromolecular ensembles (i.e., NMIIA-F stacks) but how this occurs is unknown. Here we show NMIIA-F stacks are formed through two non-mutually exclusive mechanisms: expansion and concatenation. During expansion, NMIIA molecules within the NMIIA-F spread out concurrent with addition of new NMIIA molecules. Concatenation occurs when multiple NMIIA-F/NMIIA-F stacks move together and align. We found NMIIA-F stack formation was regulated by both motor-activity and the availability of surrounding actin filaments. Furthermore, our data showed expansion and concatenation also formed the contractile ring in dividing cells. Thus, interphase and mitotic cells share similar mechanisms for creating large contractile units, and these are likely to underlie how other myosin II-based contractile systems are assembled.
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Affiliation(s)
- Aidan M Fenix
- Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Nilay Taneja
- Vanderbilt University School of Medicine, Nashville, TN 37232
| | | | - John Lewis
- Vanderbilt University School of Medicine, Nashville, TN 37232 Kalamazoo College, Kalamazoo, MI 49008
| | | | - Ryoma Ohi
- Vanderbilt University School of Medicine, Nashville, TN 37232
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21
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Abstract
A migrating cell must establish front-to-back polarity in order to move. In this issue, Juanes-Garcia et al. (2015. J. Cell Biol.http://dx.doi.org/10.1083/jcb.201407059) report that a short serine-rich motif in nonmuscle myosin IIB is required to establish the cell’s rear. This motif represents a new paradigm for what determines directional cell migration.
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Affiliation(s)
- Aidan M Fenix
- Vanderbilt University School of Medicine, Nashville, TN 37232
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