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Eddington C, Schwartz JK, Titus MA. filoVision - using deep learning and tip markers to automate filopodia analysis. J Cell Sci 2024; 137:jcs261274. [PMID: 38264939 PMCID: PMC10941656 DOI: 10.1242/jcs.261274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 01/09/2024] [Indexed: 01/25/2024] Open
Abstract
Filopodia are slender, actin-filled membrane projections used by various cell types for environment exploration. Analyzing filopodia often involves visualizing them using actin, filopodia tip or membrane markers. Due to the diversity of cell types that extend filopodia, from amoeboid to mammalian, it can be challenging for some to find a reliable filopodia analysis workflow suited for their cell type and preferred visualization method. The lack of an automated workflow capable of analyzing amoeboid filopodia with only a filopodia tip label prompted the development of filoVision. filoVision is an adaptable deep learning platform featuring the tools filoTips and filoSkeleton. filoTips labels filopodia tips and the cytosol using a single tip marker, allowing information extraction without actin or membrane markers. In contrast, filoSkeleton combines tip marker signals with actin labeling for a more comprehensive analysis of filopodia shafts in addition to tip protein analysis. The ZeroCostDL4Mic deep learning framework facilitates accessibility and customization for different datasets and cell types, making filoVision a flexible tool for automated analysis of tip-marked filopodia across various cell types and user data.
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Affiliation(s)
- Casey Eddington
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
- Graduate Program in Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jessica K. Schwartz
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Margaret A. Titus
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
- Graduate Program in Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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Chen X, Arciola JM, Lee YI, Wong PHP, Yin H, Tao Q, Jin Y, Qin X, Sweeney HL, Park H. Myo10 tail is crucial for promoting long filopodia. J Biol Chem 2024; 300:105523. [PMID: 38043799 PMCID: PMC10790087 DOI: 10.1016/j.jbc.2023.105523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/22/2023] [Accepted: 11/24/2023] [Indexed: 12/05/2023] Open
Abstract
Filopodia are slender cellular protrusions containing parallel actin bundles involved in environmental sensing and signaling, cell adhesion and migration, and growth cone guidance and extension. Myosin 10 (Myo10), an unconventional actin-based motor protein, was reported to induce filopodial initiation with its motor domain. However, the roles of the multifunctional tail domain of Myo10 in filopodial formation and elongation remain elusive. Herein, we generated several constructs of Myo10-full-length Myo10, Myo10 with a truncated tail (Myo10 HMM), and Myo10 containing four mutations to disrupt its coiled-coil domain (Myo10 CC mutant). We found that the truncation of the tail domain decreased filopodial formation and filopodial length, while four mutations in the coiled-coil domain disrupted the motion of Myo10 toward filopodial tips and the elongation of filopodia. Furthermore, we found that filopodia elongated through multiple elongation cycles, which was supported by the Myo10 tail. These findings suggest that Myo10 tail is crucial for promoting long filopodia.
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Affiliation(s)
- Xingxiang Chen
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | | | - Young Il Lee
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, USA
| | - Pak Hung Philip Wong
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Haoran Yin
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Quanqing Tao
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Yuqi Jin
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Xianan Qin
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - H Lee Sweeney
- Department of Pharmacology & Therapeutics, University of Florida College of Medicine, Gainesville, USA; Myology Institute, University of Florida College of Medicine, Gainesville, Florida, USA.
| | - Hyokeun Park
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China; Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China.
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Liu PJ, Gunther LK, Garone ME, Zhang C, Perez D, Bi-Karchin J, Pellenz CD, Chase SE, Presti MF, Plante EL, Martin CE, Lovric S, Yengo CM, Hildebrandt F, Krendel M. Steroid-Resistant Nephrotic Syndrome-Associated MYO1E Mutations Have Differential Effects on Myosin 1e Localization, Dynamics, and Activity. J Am Soc Nephrol 2022; 33:1989-2007. [PMID: 36316095 PMCID: PMC9678034 DOI: 10.1681/asn.2021111505] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 08/22/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Myo1e is a nonmuscle motor protein enriched in podocytes. Mutations in MYO1E are associated with steroid-resistant nephrotic syndrome (SRNS). Most of the MYO1E variants identified by genomic sequencing have not been functionally characterized. Here, we set out to analyze two mutations in the Myo1e motor domain, T119I and D388H, which were selected on the basis of protein sequence conservation. METHODS EGFP-tagged human Myo1e constructs were delivered into the Myo1e-KO mouse podocyte-derived cells via adenoviral infection to analyze Myo1e protein stability, Myo1e localization, and clathrin-dependent endocytosis, which is known to involve Myo1e activity. Furthermore, truncated Myo1e constructs were expressed using the baculovirus expression system and used to measure Myo1e ATPase and motor activity in vitro. RESULTS Both mutants were expressed as full-length proteins in the Myo1e-KO cells. However, unlike wild-type (WT) Myo1e, the T119I variant was not enriched at the cell junctions or clathrin-coated vesicles (CCVs). In contrast, D388H variant localization was similar to that of WT. The rate of dissociation of the D388H variant from cell-cell junctions and CCVs was decreased, suggesting this mutation affects Myo1e interactions with binding partners. ATPase activity and ability to translocate actin filaments were drastically reduced for the D388H mutant, supporting findings from cell-based experiments. CONCLUSIONS T119I and D388H mutations are deleterious to Myo1e functions. The experimental approaches used in this study can be applied to future characterization of novel MYO1E variants associated with SRNS.
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Affiliation(s)
- Pei-Ju Liu
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Laura K. Gunther
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, Pennsylvania
| | - Michael E. Garone
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Chunling Zhang
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, New York
| | - Diana Perez
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Jing Bi-Karchin
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Christopher D. Pellenz
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Sharon E. Chase
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Maria F. Presti
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Eric L. Plante
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
| | - Claire E. Martin
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, Ontario, Canada
| | - Svjetlana Lovric
- Divison of Nephrology, Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Christopher M. Yengo
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, Pennsylvania
| | - Friedhelm Hildebrandt
- Divison of Nephrology, Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Mira Krendel
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York
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Qin J, Xia PF, Yuan XZ, Wang SG. Chlorine disinfection elevates the toxicity of polystyrene microplastics to human cells by inducing mitochondria-dependent apoptosis. JOURNAL OF HAZARDOUS MATERIALS 2022; 425:127842. [PMID: 34875417 DOI: 10.1016/j.jhazmat.2021.127842] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/08/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
Microplastics (MPs) are ubiquitous in drinking water and pose potential threats to human health. Despite increasingly attentions on the toxicity of MPs, the deleterious effects of MPs after chlorine disinfection, which might be a more accessible form of MPs, has rarely been considered. Here, we first treated pristine polystyrene microplastics (PS-MPs) with chlorine to simulate the reactions that occur during drinking water treatment, and investigated and compared the cytotoxicity of chlorinated PS-MPs to those of pristine PS-MPs. Chlorine disinfection did not change the size of pristine PS-MPs, but increased the surface roughness. In addition, abundant carbon-chlorine bonds and persistent free radicals were generated on the surface of chlorinated PS-MPs. Compared with pristine PS-MPs, chlorinated PS-MPs markedly inhibited the cell proliferation, changed cellular morphology, destroyed cell membrane integrity, induced cell inflammatory response and apoptosis. Proteomics confirmed the difference in interactions with intracellular proteins between these particles. Furthermore, we found that the regulation of PI3K/AKT and Bcl-2/Bax pathways, oxidative stress-triggered mitochondrial depolarization, and the activation of caspase cascade were identified as the underlying mechanisms for the enhanced apoptosis ratio in GES-1 cells when exposed to chlorinated PS-MPs. This exacerbated cytotoxicity could be explained by the enhanced surface roughness and changed surface chemistry of these PS-MPs after chlorine disinfection. This work discloses the impacts of chlorine disinfection on the cytotoxicity of PS-MPs, which provides new insights for a more systematic risk assessment of MPs.
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Affiliation(s)
- Jing Qin
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China
| | - Peng-Fei Xia
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China
| | - Xian-Zheng Yuan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China
| | - Shu-Guang Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China.
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Matoo S, Graves MJ, Acharya P, Choi MS, Storad ZA, Idris RAES, Pickles BK, Arvay TO, Shinder PE, Gerts A, Papish JP, Crawley SW. Comparative analysis of the MyTH4-FERM myosins reveals insights into the determinants of actin track selection in polarized epithelia. Mol Biol Cell 2021; 32:ar30. [PMID: 34473561 PMCID: PMC8693963 DOI: 10.1091/mbc.e20-07-0494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
MyTH4-FERM (MF) myosins evolved to play a role in the creation and function of a variety of actin-based membrane protrusions that extend from cells. Here we performed an analysis of the MF myosins, Myo7A, Myo7B, and Myo10, to gain insight into how they select for their preferred actin networks. Using enterocytes that create spatially separated actin tracks in the form of apical microvilli and basal filopodia, we show that actin track selection is principally guided by the mode of oligomerization of the myosin along with the identity of the motor domain, with little influence from the specific composition of the lever arm. Chimeric variants of Myo7A and Myo7B fused to a leucine zipper parallel dimerization sequence in place of their native tails both selected apical microvilli as their tracks, while a truncated Myo10 used its native antiparallel coiled-coil to traffic to the tips of filopodia. Swapping lever arms between the Class 7 and 10 myosins did not change actin track preference. Surprisingly, fusing the motor-neck region of Myo10 to a leucine zipper or oligomerization sequences derived from the Myo7A and Myo7B cargo proteins USH1G and ANKS4B, respectively, re-encoded the actin track usage of Myo10 to apical microvilli with significant efficiency.
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Affiliation(s)
- Samaneh Matoo
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Maura J Graves
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Prashun Acharya
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Myoung Soo Choi
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Zachary A Storad
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | | | - Brooke K Pickles
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Taylen O Arvay
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Paula E Shinder
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Andrew Gerts
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Jacob P Papish
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Scott W Crawley
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
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Myosin-X and talin modulate integrin activity at filopodia tips. Cell Rep 2021; 36:109716. [PMID: 34525374 PMCID: PMC8456781 DOI: 10.1016/j.celrep.2021.109716] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 07/06/2021] [Accepted: 08/24/2021] [Indexed: 11/20/2022] Open
Abstract
Filopodia assemble unique integrin-adhesion complexes to sense the extracellular matrix. However, the mechanisms of integrin regulation in filopodia are poorly defined. Here, we report that active integrins accumulate at the tip of myosin-X (MYO10)-positive filopodia, while inactive integrins are uniformly distributed. We identify talin and MYO10 as the principal integrin activators in filopodia. In addition, deletion of MYO10's FERM domain, or mutation of its β1-integrin-binding residues, reveals MYO10 as facilitating integrin activation, but not transport, in filopodia. However, MYO10's isolated FERM domain alone cannot activate integrins, potentially because of binding to both integrin tails. Finally, because a chimera construct generated by swapping MYO10-FERM by talin-FERM enables integrin activation in filopodia, our data indicate that an integrin-binding FERM domain coupled to a myosin motor is a core requirement for integrin activation in filopodia. Therefore, we propose a two-step integrin activation model in filopodia: receptor tethering by MYO10 followed by talin-mediated integrin activation.
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Arthur AL, Crawford A, Houdusse A, Titus MA. VASP-mediated actin dynamics activate and recruit a filopodia myosin. eLife 2021; 10:68082. [PMID: 34042588 PMCID: PMC8352590 DOI: 10.7554/elife.68082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/20/2021] [Indexed: 11/17/2022] Open
Abstract
Filopodia are thin, actin-based structures that cells use to interact with their environments. Filopodia initiation requires a suite of conserved proteins but the mechanism remains poorly understood. The actin polymerase VASP and a MyTH-FERM (MF) myosin, DdMyo7 in amoeba, are essential for filopodia initiation. DdMyo7 is localized to dynamic regions of the actin-rich cortex. Analysis of VASP mutants and treatment of cells with anti-actin drugs shows that myosin recruitment and activation in Dictyostelium requires localized VASP-dependent actin polymerization. Targeting of DdMyo7 to the cortex alone is not sufficient for filopodia initiation; VASP activity is also required. The actin regulator locally produces a cortical actin network that activates myosin and together they shape the actin network to promote extension of parallel bundles of actin during filopodia formation. This work reveals how filopodia initiation requires close collaboration between an actin-binding protein, the state of the actin cytoskeleton and MF myosin activity.
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Affiliation(s)
- Ashley L Arthur
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
| | - Amy Crawford
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
| | - Anne Houdusse
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, Paris, France
| | - Margaret A Titus
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
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Abstract
Filopodia, microvilli and stereocilia represent an important group of plasma membrane protrusions. These specialized projections are supported by parallel bundles of actin filaments and have critical roles in sensing the external environment, increasing cell surface area, and acting as mechanosensors. While actin-associated proteins are essential for actin-filament elongation and bundling in these protrusions, myosin motors have a surprising role in the formation and extension of filopodia and stereocilia and in the organization of microvilli. Actin regulators and specific myosins collaborate in controlling the length of these structures. Myosins can transport cargoes along the length of these protrusions, and, in the case of stereocilia and microvilli, interactions with adaptors and cargoes can also serve to anchor adhesion receptors to the actin-rich core via functionally conserved motor-adaptor complexes. This review highlights recent progress in understanding the diverse roles myosins play in filopodia, microvilli and stereocilia.
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Affiliation(s)
- Anne Houdusse
- Structural Motility, Institut Curie, Paris Université Sciences et Lettres, Sorbonne Université, CNRS UMR144, 75005 Paris, France.
| | - Margaret A Titus
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA.
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Liu R, Billington N, Yang Y, Bond C, Hong A, Siththanandan V, Takagi Y, Sellers JR. A binding protein regulates myosin-7a dimerization and actin bundle assembly. Nat Commun 2021; 12:563. [PMID: 33495456 PMCID: PMC7835385 DOI: 10.1038/s41467-020-20864-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 12/07/2020] [Indexed: 01/17/2023] Open
Abstract
Myosin-7a, despite being monomeric in isolation, plays roles in organizing actin-based cell protrusions such as filopodia, microvilli and stereocilia, as well as transporting cargoes within them. Here, we identify a binding protein for Drosophila myosin-7a termed M7BP, and describe how M7BP assembles myosin-7a into a motile complex that enables cargo translocation and actin cytoskeletal remodeling. M7BP binds to the autoinhibitory tail of myosin-7a, extending the molecule and activating its ATPase activity. Single-molecule reconstitution show that M7BP enables robust motility by complexing with myosin-7a as 2:2 translocation dimers in an actin-regulated manner. Meanwhile, M7BP tethers actin, enhancing complex’s processivity and driving actin-filament alignment during processive runs. Finally, we show that myosin-7a-M7BP complex assembles actin bundles and filopodia-like protrusions while migrating along them in living cells. Together, these findings provide insights into the mechanisms by which myosin-7a functions in actin protrusions. Myosin-7a is found in actin bundles, microvilli and stereocilia, and plays conserved roles in hearing and vision. Here the authors identify M7BP, a myosin-7a binding protein that activates and dimerizes myosin-7a, enabling cargo transport and assembly of actin bundles and filopodia-like protrusions
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Affiliation(s)
- Rong Liu
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Neil Billington
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yi Yang
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.,Laboratory of Functional Proteomics, College of Veterinary Medicine, Hunan Agricultural University, 410128, Changsha, Hunan, China
| | - Charles Bond
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Amy Hong
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Verl Siththanandan
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yasuharu Takagi
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - James R Sellers
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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