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Lapshina KK, Nefedova VV, Nabiev SR, Roman SG, Shchepkin DV, Kopylova GV, Kochurova AM, Beldiia EA, Kleymenov SY, Levitsky DI, Matyushenko AM. Functional and Structural Properties of Cytoplasmic Tropomyosin Isoforms Tpm1.8 and Tpm1.9. Int J Mol Sci 2024; 25:6873. [PMID: 38999987 PMCID: PMC11240984 DOI: 10.3390/ijms25136873] [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: 05/14/2024] [Revised: 06/11/2024] [Accepted: 06/19/2024] [Indexed: 07/14/2024] Open
Abstract
The actin cytoskeleton is one of the most important players in cell motility, adhesion, division, and functioning. The regulation of specific microfilament formation largely determines cellular functions. The main actin-binding protein in animal cells is tropomyosin (Tpm). The unique structural and functional diversity of microfilaments is achieved through the diversity of Tpm isoforms. In our work, we studied the properties of the cytoplasmic isoforms Tpm1.8 and Tpm1.9. The results showed that these isoforms are highly thermostable and differ in the stability of their central and C-terminal fragments. The properties of these isoforms were largely determined by the 6th exons. Thus, the strength of the end-to-end interactions, as well as the affinity of the Tpm molecule for F-actin, differed between the Tpm1.8 and Tpm1.9 isoforms. They were determined by whether an alternative internal exon, 6a or 6b, was included in the Tpm isoform structure. The strong interactions of the Tpm1.8 and Tpm1.9 isoforms with F-actin led to the formation of rigid actin filaments, the stiffness of which was measured using an optical trap. It is quite possible that the structural and functional features of the Tpm isoforms largely determine the appearance of these isoforms in the rigid actin structures of the cell cortex.
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Affiliation(s)
- Ksenia K. Lapshina
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; (K.K.L.); (V.V.N.); (S.G.R.); (S.Y.K.); (D.I.L.)
- Department of Biophysics, Faculty of Physics, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Victoria V. Nefedova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; (K.K.L.); (V.V.N.); (S.G.R.); (S.Y.K.); (D.I.L.)
| | - Salavat R. Nabiev
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 620049 Yekaterinburg, Russia; (S.R.N.); (D.V.S.); (G.V.K.); (A.M.K.); (E.A.B.)
| | - Svetlana G. Roman
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; (K.K.L.); (V.V.N.); (S.G.R.); (S.Y.K.); (D.I.L.)
| | - Daniil V. Shchepkin
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 620049 Yekaterinburg, Russia; (S.R.N.); (D.V.S.); (G.V.K.); (A.M.K.); (E.A.B.)
| | - Galina V. Kopylova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 620049 Yekaterinburg, Russia; (S.R.N.); (D.V.S.); (G.V.K.); (A.M.K.); (E.A.B.)
| | - Anastasia M. Kochurova
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 620049 Yekaterinburg, Russia; (S.R.N.); (D.V.S.); (G.V.K.); (A.M.K.); (E.A.B.)
| | - Evgenia A. Beldiia
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 620049 Yekaterinburg, Russia; (S.R.N.); (D.V.S.); (G.V.K.); (A.M.K.); (E.A.B.)
| | - Sergey Y. Kleymenov
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; (K.K.L.); (V.V.N.); (S.G.R.); (S.Y.K.); (D.I.L.)
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia
| | - Dmitrii I. Levitsky
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; (K.K.L.); (V.V.N.); (S.G.R.); (S.Y.K.); (D.I.L.)
| | - Alexander M. Matyushenko
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; (K.K.L.); (V.V.N.); (S.G.R.); (S.Y.K.); (D.I.L.)
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Dhar A, Bagyashree VT, Biswas S, Kumari J, Sridhara A, Jeevan Subodh B, Shekhar S, Palani S. Functional redundancy and formin-independent localization of tropomyosin isoforms in Saccharomyces cerevisiae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.587703. [PMID: 38617342 PMCID: PMC11014519 DOI: 10.1101/2024.04.04.587703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Tropomyosin is an actin binding protein which protects actin filaments from cofilin-mediated disassembly. Distinct tropomyosin isoforms have long been hypothesized to differentially sort to subcellular actin networks and impart distinct functionalities. Nevertheless, a mechanistic understanding of the interplay between Tpm isoforms and their functional contributions to actin dynamics has been lacking. In this study, we present acetylation-mimic engineered mNeonGreen-Tpm fusion proteins that exhibit complete functionality as a sole copy, surpassing limitations of existing probes and enabling real-time dynamic tracking of Tpm-actin filaments in vivo. Using these functional Tpm fusion proteins, we find that both Tpm1 and Tpm2 indiscriminately bind to actin filaments nucleated by either formin isoform- Bnr1 and Bni1 in vivo, in contrast to the long-held paradigm of Tpm-formin pairing. We also show that Tpm2 can protect and organize functional actin cables in absence of Tpm1. Overall, our work supports a concentration-dependent and formin-independent model of Tpm-actin binding and demonstrates for the first time, the functional redundancy of the paralog Tpm2 in actin cable maintenance in S. cerevisiae.
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Affiliation(s)
- Anubhav Dhar
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India
- equal contribution
| | - VT Bagyashree
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India
- equal contribution
| | - Sudipta Biswas
- Departments of Physics, Cell Biology and Biochemistry, Emory University, Atlanta, GA, 30322, USA
| | - Jayanti Kumari
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Amruta Sridhara
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - B Jeevan Subodh
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Shashank Shekhar
- Departments of Physics, Cell Biology and Biochemistry, Emory University, Atlanta, GA, 30322, USA
| | - Saravanan Palani
- Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India
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3
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Ono S, Watabe E, Morisaki K, Ono K, Kuroyanagi H. Alternative splicing of a single exon causes a major impact on the affinity of Caenorhabditis elegans tropomyosin isoforms for actin filaments. Front Cell Dev Biol 2023; 11:1208913. [PMID: 37745299 PMCID: PMC10512467 DOI: 10.3389/fcell.2023.1208913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/29/2023] [Indexed: 09/26/2023] Open
Abstract
Tropomyosin is generally known as an actin-binding protein that regulates actomyosin interaction and actin filament stability. In metazoans, multiple tropomyosin isoforms are expressed, and some of them are involved in generating subpopulations of actin cytoskeleton in an isoform-specific manner. However, functions of many tropomyosin isoforms remain unknown. Here, we report identification of a novel alternative exon in the Caenorhabditis elegans tropomyosin gene and characterization of the effects of alternative splicing on the properties of tropomyosin isoforms. Previous studies have reported six tropomyosin isoforms encoded by the C. elegans lev-11 tropomyosin gene. We identified a seventh isoform, LEV-11U, that contained a novel alternative exon, exon 7c (E7c). LEV-11U is a low-molecular-weight tropomyosin isoform that differs from LEV-11T only at the exon 7-encoded region. In silico analyses indicated that the E7c-encoded peptide sequence was unfavorable for coiled-coil formation and distinct from other tropomyosin isoforms in the pattern of electrostatic surface potentials. In vitro, LEV-11U bound poorly to actin filaments, whereas LEV-11T bound to actin filaments in a saturable manner. When these isoforms were transgenically expressed in the C. elegans striated muscle, LEV-11U was present in the diffuse cytoplasm with tendency to form aggregates, whereas LEV-11T co-localized with sarcomeric actin filaments. Worms with a mutation in E7c showed reduced motility and brood size, suggesting that this exon is important for the optimal health. These results indicate that alternative splicing of a single exon can produce biochemically diverged tropomyosin isoforms and suggest that a tropomyosin isoform with poor actin affinity has a novel biological function.
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Affiliation(s)
- Shoichiro Ono
- Departments of Pathology and Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, United States
| | - Eichi Watabe
- Laboratory of Gene Expression, Graduate School of Biomedical Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keita Morisaki
- Departments of Pathology and Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Kanako Ono
- Departments of Pathology and Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, United States
| | - Hidehito Kuroyanagi
- Laboratory of Gene Expression, Graduate School of Biomedical Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Biochemistry, University of the Ryukyus Graduate School of Medicine, Okinawa, Japan
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Liu B, Shen H, He J, Jin B, Tian Y, Li W, Hou L, Zhao W, Nan J, Zhao J, Shen J, Yu H, Wang Y, Shan G, Shi L, Cai X. Cytoskeleton remodeling mediated by circRNA-YBX1 phase separation suppresses the metastasis of liver cancer. Proc Natl Acad Sci U S A 2023; 120:e2220296120. [PMID: 37459535 PMCID: PMC10372620 DOI: 10.1073/pnas.2220296120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 05/22/2023] [Indexed: 07/20/2023] Open
Abstract
Metastasis, especially intrahepatic, is a major challenge for hepatocellular carcinoma (HCC) treatment. Cytoskeleton remodeling has been identified as a vital process mediating intrahepatic spreading. Previously, we reported that HCC tumor adhesion and invasion were modulated by circular RNA (circRNA), which has emerged as an important regulator of various cellular processes and has been implicated in cancer progression. Here, we uncovered a nuclear circRNA, circASH2, which is preferentially lost in HCC tissues and inhibits HCC metastasis by altering tumor cytoskeleton structure. Tropomyosin 4 (TPM4), a critical binding protein of actin, turned out to be the major target of circASH2 and was posttranscriptionally suppressed. Such regulation is based on messenger RNA (mRNA)/precursormRNA splicing and degradation process. Furthermore, liquid-liquid phase separation of nuclear Y-box binding protein 1 (YBX1) enhanced by circASH2 augments TPM4 transcripts decay. Together, our data have revealed a tumor-suppressive circRNA and, more importantly, uncovered a fine regulation mechanism for HCC progression.
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Affiliation(s)
- Boqiang Liu
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Hao Shen
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Jing He
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Binghan Jin
- Department of Endocrinology, The Children's Hospital, School of Medicine, National Clinical Research Center for Child Health, Zhejiang University, Hangzhou310053, China
| | - Yuanshi Tian
- Department of Diagnostic Ultrasound & Echocardiography, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
| | - Weiqi Li
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Lidan Hou
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Weijun Zhao
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Junjie Nan
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Jia Zhao
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
| | - Jiliang Shen
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Hong Yu
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Yifan Wang
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Ge Shan
- Zhejiang University Cancer Center, Zhejiang University, Hangzhou310030, China
- Department of Pulmonary and Critical Care Medicine, Regional medical center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Division of Life Science and Medicine, Department of Clinical Laboratory, First Affiliated Hospital of the University of Science and Technology of China, Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, University of Science and Technology of China, Hefei230027, China
| | - Liang Shi
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
| | - Xiujun Cai
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou310016, China
- Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Zhejiang University, Hangzhou310016, China
- Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Hangzhou310016, China
- Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Hangzhou310016, China
- Zhejiang University Cancer Center, Zhejiang University, Hangzhou310030, China
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Logvinov AS, Nefedova VV, Yampolskaya DS, Kleymenov SY, Levitsky DI, Matyushenko AM. Structural and Functional Properties of Tropomyosin Isoforms Tpm4.1 and Tpm2.1. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:801-809. [PMID: 37748876 DOI: 10.1134/s0006297923060081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/05/2023] [Accepted: 05/10/2023] [Indexed: 09/27/2023]
Abstract
Tropomyosin (Tpm) is one of the most important partners of actin filament that largely determines its properties. In animal organisms, there are different isoforms of Tpm, which are believed to be involved in the regulation of various cellular functions. However, molecular mechanisms by which various Tpm cytoplasmic regulate of the functioning of actin filaments are still poorly understood. Here, we investigated the properties of Tpm2.1 and Tpm4.1 isoforms and compared them to each other and to more extensively studied Tpm isoforms. Tpm2.1 and Tpm4.1 were very similar in their affinity to F-actin, thermal stability, and resistance to limited proteolysis by trypsin, but differed markedly in the viscosity of their solutions and thermal stability of their complexes with F-actin. The main difference of Tpm2.1 and Tpm4.1 from other Tpm isoforms (e.g., Tpm1.6 and Tpm1.7) was their extremely low thermal stability as measured by the CD and DSC methods. We suggested the possible causes of this instability based on comparing the amino acid sequences of Tpm4.1 and Tpm2.1 with the sequences of Tpm1.6 and Tpm1.7 isoforms, respectively, that have similar exon structure.
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Affiliation(s)
- Andrey S Logvinov
- Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Victoria V Nefedova
- Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Daria S Yampolskaya
- Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Sergey Y Kleymenov
- Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Dmitrii I Levitsky
- Research Centre of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
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Abood A, Mesner LD, Jeffery ED, Murali M, Lehe M, Saquing J, Farber CR, Sheynkman GM. Long-read proteogenomics to connect disease-associated sQTLs to the protein isoform effectors of disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.17.531557. [PMID: 36993769 PMCID: PMC10055087 DOI: 10.1101/2023.03.17.531557] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
A major fraction of loci identified by genome-wide association studies (GWASs) lead to alterations in alternative splicing, but interpretation of how such alterations impact proteins is hindered by the technical limitations of short-read RNA-seq, which cannot directly link splicing events to full-length transcript or protein isoforms. Long-read RNA-seq represents a powerful tool to define and quantify transcript isoforms, and recently, infer protein isoform existence. Here we present a novel approach that integrates information from GWAS, splicing QTL (sQTL), and PacBio long-read RNA-seq in a disease-relevant model to infer the effects of sQTLs on the ultimate protein isoform products they encode. We demonstrate the utility of our approach using bone mineral density (BMD) GWAS data. We identified 1,863 sQTLs from the Genotype-Tissue Expression (GTEx) project in 732 protein-coding genes which colocalized with BMD associations (H 4 PP ≥ 0.75). We generated deep coverage PacBio long-read RNA-seq data (N=∼22 million full-length reads) on human osteoblasts, identifying 68,326 protein-coding isoforms, of which 17,375 (25%) were novel. By casting the colocalized sQTLs directly onto protein isoforms, we connected 809 sQTLs to 2,029 protein isoforms from 441 genes expressed in osteoblasts. Using these data, we created one of the first proteome-scale resources defining full-length isoforms impacted by colocalized sQTLs. Overall, we found that 74 sQTLs influenced isoforms likely impacted by nonsense mediated decay (NMD) and 190 that potentially resulted in the expression of new protein isoforms. Finally, we identified colocalizing sQTLs in TPM2 for splice junctions between two mutually exclusive exons, and two different transcript termination sites, making it impossible to interpret without long-read RNA-seq data. siRNA mediated knockdown in osteoblasts showed two TPM2 isoforms with opposing effects on mineralization. We expect our approach to be widely generalizable across diverse clinical traits and accelerate system-scale analyses of protein isoform activities modulated by GWAS loci.
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Selvaraj M, Kokate SB, Reggiano G, Kogan K, Kotila T, Kremneva E, DiMaio F, Lappalainen P, Huiskonen JT. Structural basis underlying specific biochemical activities of non-muscle tropomyosin isoforms. Cell Rep 2023; 42:111900. [PMID: 36586407 DOI: 10.1016/j.celrep.2022.111900] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 11/03/2022] [Accepted: 12/07/2022] [Indexed: 12/31/2022] Open
Abstract
The actin cytoskeleton is critical for cell migration, morphogenesis, endocytosis, organelle dynamics, and cytokinesis. To support diverse cellular processes, actin filaments form a variety of structures with specific architectures and dynamic properties. Key proteins specifying actin filaments are tropomyosins. Non-muscle cells express several functionally non-redundant tropomyosin isoforms, which differentially control the interactions of other proteins, including myosins and ADF/cofilin, with actin filaments. However, the underlying molecular mechanisms have remained elusive. By determining the cryogenic electron microscopy structures of actin filaments decorated by two functionally distinct non-muscle tropomyosin isoforms, Tpm1.6 and Tpm3.2, we reveal that actin filament conformation remains unaffected upon binding. However, Tpm1.6 and Tpm3.2 follow different paths along the actin filament major groove, providing an explanation for their incapability to co-polymerize on actin filaments. We also elucidate the molecular basis underlying specific roles of Tpm1.6 and Tpm3.2 in myosin II activation and protecting actin filaments from ADF/cofilin-catalyzed severing.
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Affiliation(s)
- Muniyandi Selvaraj
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Shrikant B Kokate
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Gabriella Reggiano
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Konstantin Kogan
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Tommi Kotila
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Elena Kremneva
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Pekka Lappalainen
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
| | - Juha T Huiskonen
- Institute of Biotechnology, Helsinki Institute of Life Science HiLIFE, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
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Clostridium novyi’s Alpha-Toxin Changes Proteome and Phosphoproteome of HEp-2 Cells. Int J Mol Sci 2022; 23:ijms23179939. [PMID: 36077344 PMCID: PMC9456407 DOI: 10.3390/ijms23179939] [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] [Received: 07/20/2022] [Revised: 08/17/2022] [Accepted: 08/27/2022] [Indexed: 11/16/2022] Open
Abstract
C. novyi type A produces the alpha-toxin (TcnA) that belongs to the large clostridial glucosylating toxins (LCGTs) and is able to modify small GTPases by N-acetylglucosamination on conserved threonine residues. In contrast, other LCGTs including Clostridioides difficile toxin A and toxin B (TcdA; TcdB) modify small GTPases by mono-o-glucosylation. Both modifications inactivate the GTPases and cause strong effects on GTPase-dependent signal transduction pathways and the consequent reorganization of the actin cytoskeleton leading to cell rounding and finally cell death. However, the effect of TcnA on target cells is largely unexplored. Therefore, we performed a comprehensive screening approach of TcnA treated HEp-2 cells and analyzed their proteome and their phosphoproteome using LC-MS-based methods. With this data-dependent acquisition (DDA) approach, 5086 proteins and 9427 phosphosites could be identified and quantified. Of these, 35 proteins were found to be significantly altered after toxin treatment, and 1832 phosphosites were responsive to TcnA treatment. By analyzing the TcnA-induced proteomic effects of HEp-2 cells, 23 common signaling pathways were identified to be altered, including Actin Cytoskeleton Signaling, Epithelial Adherens Junction Signaling, and Signaling by Rho Family GTPases. All these pathways are also regulated after application of TcdA or TcdB of C. difficile. After TcnA treatment the regulation on phosphorylation level was much stronger compared to the proteome level, in terms of both strength of regulation and the number of regulated phosphosites. Interestingly, various signaling pathways such as Signaling by Rho Family GTPases or Integrin Signaling were activated on proteome level while being inhibited on phosphorylation level or vice versa as observed for the Role of BRCA1 in DNA Damage Response. ZIP kinase, as well as Calmodulin-dependent protein kinases IV & II, were observed as activated while Aurora-A kinase and CDK kinases tended to be inhibited in cells treated with TcnA based on their substrate regulation pattern.
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Wang J, Yang Y, Du B. Clinical Characterization and Prognostic Value of TPM4 and Its Correlation with Epithelial–Mesenchymal Transition in Glioma. Brain Sci 2022; 12:brainsci12091120. [PMID: 36138856 PMCID: PMC9497136 DOI: 10.3390/brainsci12091120] [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] [Received: 07/26/2022] [Revised: 08/19/2022] [Accepted: 08/21/2022] [Indexed: 11/26/2022] Open
Abstract
Tropomyosin 4 (TPM4) has been reported as an oncogenic gene across different malignancies. However, the role of TPM4 in glioma remains unclear. This study aimed to determine the clinical characterization and prognostic value of TPM4 in gliomas. Transcriptome expression and clinical information were collected from the CGGA and TCGA datasets, which included 998 glioma patients. ScRNA-seq data were obtained from CGGA. R software was utilized for statistical analyses. There was a positive correlation between TPM4 and WHO grades. IDH-wildtype and mesenchymal subtype gliomas were accompanied by TPM4 upregulation. GO and GSEA analysis suggested that TPM4 was profoundly associated with epithelial-to-mesenchymal transition (EMT). Subsequent GSVA revealed a robust correlation between TPM4 and three signaling pathways of EMT (hypoxia, TGF-β, PI3K/AKT). Furthermore, TPM4 showed a synergistic effect with mesenchymal biomarkers, particularly with N-cadherin, Slug, Snail, TWIST1, and vimentin. ScRNA-seq analysis suggested that higher TPM4 was mainly attributed to tumor cells and macrophages and associated with tumor cell progression and macrophage polarization. Finally, high TPM4 was significantly associated with unfavorable outcomes. In conclusion, our findings indicate that TPM4 is significantly correlated with more malignant characteristics of gliomas, potentially through involvement in EMT. TPM4 could predict worse survival for patients with glioma.
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Affiliation(s)
- Jin Wang
- Department of Emergency, Shenzhen People’s Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University), Shenzhen 518020, China
| | - Ying Yang
- Department of Pediatrics, Futian Women and Children Health Institute, Shenzhen 518045, China
| | - Bo Du
- Department of Emergency, Shenzhen People’s Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University), Shenzhen 518020, China
- Correspondence: ; Tel.: +86-159-1414-1979
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10
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McAdow J, Yang S, Ou T, Huang G, Dobbs MB, Gurnett CA, Greenberg MJ, Johnson AN. A pathogenic mechanism associated with myopathies and structural birth defects involves TPM2-directed myogenesis. JCI Insight 2022; 7:152466. [PMID: 35579956 PMCID: PMC9309062 DOI: 10.1172/jci.insight.152466] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 05/13/2022] [Indexed: 11/18/2022] Open
Abstract
Nemaline myopathy (NM) is the most common congenital myopathy, characterized by extreme weakness of the respiratory, limb, and facial muscles. Pathogenic variants in Tropomyosin 2 (TPM2), which encodes a skeletal muscle-specific actin binding protein essential for sarcomere function, cause a spectrum of musculoskeletal disorders that include NM as well as cap myopathy, congenital fiber type disproportion, and distal arthrogryposis (DA). The in vivo pathomechanisms underlying TPM2-related disorders are unknown, so we expressed a series of dominant, pathogenic TPM2 variants in Drosophila embryos and found 4 variants significantly affected muscle development and muscle function. Transient overexpression of the 4 variants also disrupted the morphogenesis of mouse myotubes in vitro and negatively affected zebrafish muscle development in vivo. We used transient overexpression assays in zebrafish to characterize 2 potentially novel TPM2 variants and 1 recurring variant that we identified in patients with DA (V129A, E139K, A155T, respectively) and found these variants caused musculoskeletal defects similar to those of known pathogenic variants. The consistency of musculoskeletal phenotypes in our assays correlated with the severity of clinical phenotypes observed in our patients with DA, suggesting disrupted myogenesis is a potentially novel pathomechanism of TPM2 disorders and that our myogenic assays can predict the clinical severity of TPM2 variants.
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Affiliation(s)
- Jennifer McAdow
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Shuo Yang
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Tiffany Ou
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Gary Huang
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Matthew B Dobbs
- Paley Orthopedic and Spine Institute, West Palm Beach, Florida, USA
| | - Christina A Gurnett
- Department of Neurology.,Department of Orthopedic Surgery.,Department of Pediatrics, and
| | - Michael J Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Aaron N Johnson
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, Missouri, USA
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11
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Alternative splicing diversifies the skeletal muscle transcriptome during prolonged spaceflight. Skelet Muscle 2022; 12:11. [PMID: 35642060 PMCID: PMC9153194 DOI: 10.1186/s13395-022-00294-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/05/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As the interest in manned spaceflight increases, so does the requirement to understand the transcriptomic mechanisms that underlay the detrimental physiological adaptations of skeletal muscle to microgravity. While microgravity-induced differential gene expression (DGE) has been extensively investigated, the contribution of differential alternative splicing (DAS) to the plasticity and functional status of the skeletal muscle transcriptome has not been studied in an animal model. Therefore, by evaluating both DGE and DAS across spaceflight, we set out to provide the first comprehensive characterization of the transcriptomic landscape of skeletal muscle during exposure to microgravity. METHODS RNA-sequencing, immunohistochemistry, and morphological analyses were conducted utilizing total RNA and tissue sections isolated from the gastrocnemius and quadriceps muscles of 30-week-old female BALB/c mice exposed to microgravity or ground control conditions for 9 weeks. RESULTS In response to microgravity, the skeletal muscle transcriptome was remodeled via both DGE and DAS. Importantly, while DGE showed variable gene network enrichment, DAS was enriched in structural and functional gene networks of skeletal muscle, resulting in the expression of alternatively spliced transcript isoforms that have been associated with the physiological changes to skeletal muscle in microgravity, including muscle atrophy and altered fiber type function. Finally, RNA-binding proteins, which are required for regulation of pre-mRNA splicing, were themselves differentially spliced but not differentially expressed, an upstream event that is speculated to account for the downstream splicing changes identified in target skeletal muscle genes. CONCLUSIONS Our work serves as the first investigation of coordinate changes in DGE and DAS in large limb muscles across spaceflight. It opens up a new opportunity to understand (i) the molecular mechanisms by which splice variants of skeletal muscle genes regulate the physiological adaptations of skeletal muscle to microgravity and (ii) how small molecule splicing regulator therapies might thwart muscle atrophy and alterations to fiber type function during prolonged spaceflight.
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12
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Reindl T, Giese S, Greve JN, Reinke PY, Chizhov I, Latham SL, Mulvihill DP, Taft MH, Manstein DJ. Distinct actin–tropomyosin cofilament populations drive the functional diversification of cytoskeletal myosin motor complexes. iScience 2022; 25:104484. [PMID: 35720262 PMCID: PMC9204724 DOI: 10.1016/j.isci.2022.104484] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/02/2022] [Accepted: 05/24/2022] [Indexed: 11/02/2022] Open
Abstract
The effects of N-terminal acetylation of the high molecular weight tropomyosin isoforms Tpm1.6 and Tpm2.1 and the low molecular weight isoforms Tpm1.12, Tpm3.1, and Tpm4.2 on the actin affinity and the thermal stability of actin-tropomyosin cofilaments are described. Furthermore, we show how the exchange of cytoskeletal tropomyosin isoforms and their N-terminal acetylation affects the kinetic and chemomechanical properties of cytoskeletal actin-tropomyosin-myosin complexes. Our results reveal the extent to which the different actin-tropomyosin-myosin complexes differ in their kinetic and functional properties. The maximum sliding velocity of the actin filament as well as the optimal motor density for continuous unidirectional movement, parameters that were previously considered to be unique and invariant properties of each myosin isoform, are shown to be influenced by the exchange of the tropomyosin isoform and the N-terminal acetylation of tropomyosin. Tpm diversity is largely determined by sequences contributing to the overlap region Global sequence differences are of greater importance than variable exon 6 usage Tpm isoforms confer distinctly altered properties to cytoskeletal myosin motors Cytoskeletal myosins are differentially affected by N-terminal acetylation of Tpm
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13
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Dias C, Nita E, Faktor J, Tynan AC, Hernychova L, Vojtesek B, Nylandsted J, Hupp TR, Kunath T, Ball KL. CHIP-dependent regulation of the actin cytoskeleton is linked to neuronal cell membrane integrity. iScience 2021; 24:102878. [PMID: 34401662 PMCID: PMC8350547 DOI: 10.1016/j.isci.2021.102878] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 04/13/2021] [Accepted: 07/15/2021] [Indexed: 12/12/2022] Open
Abstract
CHIP is an E3-ubiquitin ligase that contributes to healthy aging and has been characterized as neuroprotective. To elucidate dominant CHIP-dependent changes in protein steady-state levels in a patient-derived human neuronal model, CHIP function was ablated using gene-editing and an unbiased proteomic analysis conducted to compare knock-out and wild-type isogenic induced pluripotent stem cell (iPSC)-derived cortical neurons. Rather than a broad effect on protein homeostasis, loss of CHIP function impacted on a focused cohort of proteins from actin cytoskeleton signaling and membrane integrity networks. In support of the proteomics, CHIP knockout cells had enhanced sensitivity to induced membrane damage. We conclude that the major readout of CHIP function in cortical neurons derived from iPSC of a patient with elevate α-synuclein, Parkinson's disease and dementia, is the modulation of substrates involved in maintaining cellular "health". Thus, regulation of the actin cytoskeletal and membrane integrity likely contributes to the neuroprotective function(s) of CHIP.
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Affiliation(s)
- Catarina Dias
- Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
- Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, The University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Erisa Nita
- Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Jakub Faktor
- Research Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, 656 53 Brno, Czech Republic
- University of Gdansk, International Centre for Cancer Vaccine Science, 80-822 Gdansk, Poland
| | - Ailish C. Tynan
- Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Lenka Hernychova
- Research Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, 656 53 Brno, Czech Republic
| | - Borivoj Vojtesek
- Research Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, 656 53 Brno, Czech Republic
| | - Jesper Nylandsted
- Membrane Integrity Group, Danish Cancer Society Research Center, Strandboulevarden 49, 2100, Copenhagen, Denmark
| | - Ted R. Hupp
- Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
- University of Gdansk, International Centre for Cancer Vaccine Science, 80-822 Gdansk, Poland
| | - Tilo Kunath
- Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, The University of Edinburgh, Edinburgh EH16 4UU, UK
| | - Kathryn L. Ball
- Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
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14
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Marchenko MA, Nefedova VV, Yampolskaya DS, Borzova VA, Kleymenov SY, Nabiev SR, Nikitina LV, Matyushenko AM, Levitsky DI. Comparative structural and functional studies of low molecular weight tropomyosin isoforms, the TPM3 gene products. Arch Biochem Biophys 2021; 710:108999. [PMID: 34339666 DOI: 10.1016/j.abb.2021.108999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/06/2021] [Accepted: 07/20/2021] [Indexed: 10/20/2022]
Abstract
Tropomyosin (Tpm) is an actin-associated protein and key regulator of actin filament structure and dynamics in muscle and non-muscle cells where it participates in many vital processes. Human non-muscle cells produce many Tpm isoforms; however, little is known yet about their structural and functional properties. In the present work, we have applied various methods to investigate the properties of five low molecular weight Tpm isoforms (Tpm3.1, Tpm3.2, Tpm3.4, Tpm3.5, and Tpm3.7), the products of TPM3 gene, which significantly differ by alternatively spliced internal exon 6 (6a or 6b) and C-terminal exon 9 (9a, 9c or 9d). Our results clearly demonstrate that the properties of these Tpm isoforms are quite different depending on sequence variations in alternatively spliced regions of their molecules. These differences can be important in further studies to explain why these Tpm isoforms play a key role in organization and dynamics of the cytoskeleton.
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Affiliation(s)
- Marina A Marchenko
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, 119071, Moscow, Russia; Department of Biochemistry, School of Biology, Moscow State University, Moscow, 119234, Russia
| | - Victoria V Nefedova
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, 119071, Moscow, Russia
| | - Daria S Yampolskaya
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, 119071, Moscow, Russia
| | - Vera A Borzova
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, 119071, Moscow, Russia
| | - Sergey Y Kleymenov
- Koltzov Institute of Developmental Biology of the Russian Academy of Sciences, 119334, Moscow, Russia
| | - Salavat R Nabiev
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Larisa V Nikitina
- Institute of Immunology and Physiology, Russian Academy of Sciences, Yekaterinburg, 620049, Russia
| | - Alexander M Matyushenko
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, 119071, Moscow, Russia
| | - Dmitrii I Levitsky
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, 119071, Moscow, Russia.
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15
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Marchenko M, Nefedova V, Artemova N, Kleymenov S, Levitsky D, Matyushenko A. Structural and Functional Peculiarities of Cytoplasmic Tropomyosin Isoforms, the Products of TPM1 and TPM4 Genes. Int J Mol Sci 2021; 22:ijms22105141. [PMID: 34067970 PMCID: PMC8152229 DOI: 10.3390/ijms22105141] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/30/2021] [Accepted: 05/09/2021] [Indexed: 12/26/2022] Open
Abstract
Tropomyosin (Tpm) is one of the major protein partners of actin. Tpm molecules are α-helical coiled-coil protein dimers forming a continuous head-to-tail polymer along the actin filament. Human cells produce a large number of Tpm isoforms that are thought to play a significant role in determining actin cytoskeletal functions. Even though the role of these Tpm isoforms in different non-muscle cells is more or less studied in many laboratories, little is known about their structural and functional properties. In the present work, we have applied various methods to investigate the properties of five cytoplasmic Tpm isoforms (Tpm1.5, Tpm 1.6, Tpm1.7, Tpm1.12, and Tpm 4.2), which are the products of two different genes, TPM1 and TPM4, and also significantly differ by alternatively spliced exons: N-terminal exons 1a2b or 1b, internal exons 6a or 6b, and C-terminal exons 9a, 9c or 9d. Our results demonstrate that structural and functional properties of these Tpm isoforms are quite different depending on sequence variations in alternatively spliced regions of their molecules. The revealed differences can be important in further studies to explain why various Tpm isoforms interact uniquely with actin filaments, thus playing an important role in the organization and dynamics of the cytoskeleton.
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Affiliation(s)
- Marina Marchenko
- Research Center of Biotechnology, A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, 119071 Moscow, Russia; (M.M.); (V.N.); (N.A.); (D.L.)
- Department of Biochemistry, School of Biology, Moscow State University, 119234 Moscow, Russia
| | - Victoria Nefedova
- Research Center of Biotechnology, A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, 119071 Moscow, Russia; (M.M.); (V.N.); (N.A.); (D.L.)
| | - Natalia Artemova
- Research Center of Biotechnology, A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, 119071 Moscow, Russia; (M.M.); (V.N.); (N.A.); (D.L.)
| | - Sergey Kleymenov
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia;
| | - Dmitrii Levitsky
- Research Center of Biotechnology, A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, 119071 Moscow, Russia; (M.M.); (V.N.); (N.A.); (D.L.)
| | - Alexander Matyushenko
- Research Center of Biotechnology, A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, 119071 Moscow, Russia; (M.M.); (V.N.); (N.A.); (D.L.)
- Correspondence: ; Tel.: +7-926-1654430
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16
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Li J, Zhu G, Kang X, Shen X, Chen S, Tang S, Gong Q, Li Y, Xu H. Association Between TPM1 Gene Polymorphisms and Idiopathic Congenital Talipes Equinovarus Risk in a Chinese Population. Genet Test Mol Biomarkers 2021; 25:355-360. [PMID: 33945307 DOI: 10.1089/gtmb.2020.0248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Idiopathic congenital talipes equinovarus (ICTEV) is one of the most common congenital deformities of children, and dysplasia of the striated muscle may be one of the causes of ICTEV. Previous studies have shown that polymorphisms of the rs4075583 SNP in the tropomyosin gene 1 (TPM1) were associated with ICTEV in Caucasian children. However, there are no studies investigating the correlations of TPM gene polymorphisms with the risk of ICTEV in Chinese children. Methods: We conducted a case-control study, including 430 children with ICTEV and 891 ICTEV-free children. We explored the potential correlations of three TPM gene polymorphisms (TPM1/rs4075583 G>A, tropomyosin gene 2 (TPM2)/rs2145925 C>T, and TPM2/rs2025126 G>A) with ICTEV risk. The three single nucleotide polymorphisms (SNPs) were genotyped using a TaqMan method. We calculated the odds ratios (ORs) and adjusted ORs and their 95% confidence intervals (CIs) to explore the associations between these selected SNP polymorphisms and ICTEV. Results: TPM1 rs4075583 A was found to be associated with an increased ICTEV risk (AA vs. GG: adjusted OR = 1.70, 95% CI = 1.15-2.49, p = 0.007; and GG/GA vs. AA: adjusted OR = 1.62, 95% CI = 1.14-2.31, p = 0.0071) after adjusting for age and sex. In addition, a risk effect of rs4075583 GA/AA with ICETV was observed for patients with affected right feet (adjusted OR = 1.62, 95% CI = 1.10-2.39, p = 0.014) in the stratified analysis. However, there were no significant differences in the risk for ICTEV associated with the rs2145925 and rs2025126 polymorphisms. Conclusion: These results indicate that the TPM1 rs4075583 G > A polymorphism is associated with ICTEV risk in a southern Chinese population; however, this finding needs to be confirmed in larger studies and through mechanistic studies.
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Affiliation(s)
- Jingchun Li
- Department of Paediatric Orthopaedics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
| | - Guanghui Zhu
- Department of Pediatric Orthopedics, Hunan Children's Hospital, Changsha, China
| | - Xiaopeng Kang
- Department of Pediatric Orthopedics, Kunming Children's Hospital, Kunming, China
| | - Xiantao Shen
- Department of Pediatric Orthopedics, Wuhan Medical and Healthcare Center for Women and Children, Wuhan, China
| | - Shunyou Chen
- Department of Pediatric Orthopedics, Fuzhou second Hospital of Xiamen University, Fuzhou, China
| | - Shengping Tang
- Department of the First Orthopaedics, Shenzhen Children's Hospital, Shenzhen, China
| | - Qian Gong
- Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Yiqiang Li
- Department of Paediatric Orthopaedics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
| | - Hongwen Xu
- Department of Paediatric Orthopaedics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, China
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17
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Kostan J, Pavšič M, Puž V, Schwarz TC, Drepper F, Molt S, Graewert MA, Schreiner C, Sajko S, van der Ven PFM, Onipe A, Svergun DI, Warscheid B, Konrat R, Fürst DO, Lenarčič B, Djinović-Carugo K. Molecular basis of F-actin regulation and sarcomere assembly via myotilin. PLoS Biol 2021; 19:e3001148. [PMID: 33844684 PMCID: PMC8062120 DOI: 10.1371/journal.pbio.3001148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/22/2021] [Accepted: 02/16/2021] [Indexed: 12/25/2022] Open
Abstract
Sarcomeres, the basic contractile units of striated muscle cells, contain arrays of thin (actin) and thick (myosin) filaments that slide past each other during contraction. The Ig-like domain-containing protein myotilin provides structural integrity to Z-discs-the boundaries between adjacent sarcomeres. Myotilin binds to Z-disc components, including F-actin and α-actinin-2, but the molecular mechanism of binding and implications of these interactions on Z-disc integrity are still elusive. To illuminate them, we used a combination of small-angle X-ray scattering, cross-linking mass spectrometry, and biochemical and molecular biophysics approaches. We discovered that myotilin displays conformational ensembles in solution. We generated a structural model of the F-actin:myotilin complex that revealed how myotilin interacts with and stabilizes F-actin via its Ig-like domains and flanking regions. Mutant myotilin designed with impaired F-actin binding showed increased dynamics in cells. Structural analyses and competition assays uncovered that myotilin displaces tropomyosin from F-actin. Our findings suggest a novel role of myotilin as a co-organizer of Z-disc assembly and advance our mechanistic understanding of myotilin's structural role in Z-discs.
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Affiliation(s)
- Julius Kostan
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Vid Puž
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Thomas C. Schwarz
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Friedel Drepper
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Sibylle Molt
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | | | - Claudia Schreiner
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Sara Sajko
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Peter F. M. van der Ven
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Adekunle Onipe
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, Hamburg Unit, c/o DESY, Hamburg, Germany
| | - Bettina Warscheid
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Robert Konrat
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Dieter O. Fürst
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
- Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Kristina Djinović-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
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18
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Cancer type-specific alterations in actin genes: Worth a closer look? INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 360:133-184. [PMID: 33962749 DOI: 10.1016/bs.ircmb.2021.02.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Actins form a strongly conserved family of proteins that are central to the functioning of the actin cytoskeleton partaking in natural processes such as cell division, adhesion, contraction and migration. These processes, however, also occur during the various phases of cancer progression. Yet, surprisingly, alterations in the six human actin genes in cancer studies have received little attention and the focus was mostly on deregulated expression levels of actins and even more so of actin-binding or regulatory proteins. Starting from the early mutation work in the 1980s, we propose based on reviewing literature and data from patient cancer genomes that alterations in actin genes are different in distinct cancer subtypes, suggesting some specificity. These actin gene alterations include (missense) mutations, gene fusions and copy number alterations (deletions and amplifications) and we illustrate their occurrence for a limited number of examples including actin mutations in lymphoid cancers and nonmelanoma skin cancer and actin gene copy number alterations for breast, prostate and liver cancers. A challenge in the future will be to further sort out the specificity per actin gene, alteration type and cancer subtype. Even more challenging is (experimentally) distinguishing between cause and consequence: which alterations are passengers and which are involved in tumor progression of particular cancer subtypes?
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19
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Reticular Basement Membrane Thickness Is Associated with Growth- and Fibrosis-Promoting Airway Transcriptome Profile-Study in Asthma Patients. Int J Mol Sci 2021; 22:ijms22030998. [PMID: 33498209 PMCID: PMC7863966 DOI: 10.3390/ijms22030998] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/15/2021] [Accepted: 01/17/2021] [Indexed: 12/24/2022] Open
Abstract
Airway remodeling in asthma is characterized by reticular basement membrane (RBM) thickening, likely related to epithelial structural and functional changes. Gene expression profiling of the airway epithelium might identify genes involved in bronchial structural alterations. We analyzed bronchial wall geometry (computed tomography (CT)), RBM thickness (histology), and the bronchial epithelium transcriptome profile (gene expression array) in moderate to severe persistent (n = 21) vs. no persistent (n = 19) airflow limitation asthmatics. RBM thickness was similar in the two studied subgroups. Among the genes associated with increased RBM thickness, the most essential were those engaged in cell activation, proliferation, and growth (e.g., CDK20, TACC2, ORC5, and NEK5) and inhibiting apoptosis (e.g., higher mRNA expression of RFN34, BIRC3, NAA16, and lower of RNF13, MRPL37, CACNA1G). Additionally, RBM thickness correlated with the expression of genes encoding extracellular matrix (ECM) components (LAMA3, USH2A), involved in ECM remodeling (LTBP1), neovascularization (FGD5, HPRT1), nerve functioning (TPH1, PCDHGC4), oxidative stress adaptation (RIT1, HSP90AB1), epigenetic modifications (OLMALINC, DNMT3A), and the innate immune response (STAP1, OAS2). Cluster analysis revealed that genes linked with RBM thickness were also related to thicker bronchial walls in CT. Our study suggests that the pro-fibrotic profile in the airway epithelial cell transcriptome is associated with a thicker RBM, and thus, may contribute to asthma airway remodeling.
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Parreno J, Amadeo MB, Kwon EH, Fowler VM. Tropomyosin 3.1 Association With Actin Stress Fibers is Required for Lens Epithelial to Mesenchymal Transition. Invest Ophthalmol Vis Sci 2021; 61:2. [PMID: 32492110 PMCID: PMC7415280 DOI: 10.1167/iovs.61.6.2] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Purpose Epithelial to mesenchymal transition (EMT) is a cause of anterior and posterior subcapsular cataracts. Central to EMT is the formation of actin stress fibers. Selective targeting of actin stress fiber-associated tropomyosin (Tpm) in epithelial cells may be a means to prevent stress fiber formation and repress lens EMT. Methods We identified Tpm isoforms in mouse immortalized lens epithelial cells and epithelial and fiber cells from whole lenses by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) followed Sanger sequencing. We focused on the role of one particular tropomyosin isoform, Tpm3.1, in EMT. To induce EMT, we treated cells or native lenses with TGFβ2. To test the function of Tpm3.1, we exposed cells or whole lenses to a Tpm3.1-specific chemical inhibitor, TR100, as well as investigated lenses from Tpm3.1 knockout mice. We examined stress fiber formation by confocal microscopy and assessed EMT progression by analysis of alpha-smooth muscle actin (αSMA) mRNA (real-time RT-PCR), and protein (Western immunoassay [WES]). Results Lens epithelial cells express eight Tpm isoforms. Cell culture studies showed that TGFβ2 treatment results in the upregulation of Tpm3.1, which associates with actin in stress fibers. TR100 prevents stress fiber formation and reduces αSMA in TGFβ2-treated cells. Using an ex vivo lens culture model, TGFβ2 treatment results in stress fiber formation at the basal regions of the epithelial cells. Genetic knockout of Tpm3.1 or treatment of lenses with TR100 prevents basal stress fiber formation and reduces epithelial αSMA levels. Conclusions Targeting specific stress fiber associated tropomyosin isoform, Tpm3.1, is a means to repress lens EMT.
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21
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Bareja I, Wioland H, Janco M, Nicovich PR, Jégou A, Romet-Lemonne G, Walsh J, Böcking T. Dynamics of Tpm1.8 domains on actin filaments with single-molecule resolution. Mol Biol Cell 2020; 31:2452-2462. [PMID: 32845787 PMCID: PMC7851853 DOI: 10.1091/mbc.e19-10-0586] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 01/28/2023] Open
Abstract
Tropomyosins regulate the dynamics and functions of the actin cytoskeleton by forming long chains along the two strands of actin filaments that act as gatekeepers for the binding of other actin-binding proteins. The fundamental molecular interactions underlying the binding of tropomyosin to actin are still poorly understood. Using microfluidics and fluorescence microscopy, we observed the binding of the fluorescently labeled tropomyosin isoform Tpm1.8 to unlabeled actin filaments in real time. This approach, in conjunction with mathematical modeling, enabled us to quantify the nucleation, assembly, and disassembly kinetics of Tpm1.8 on single filaments and at the single-molecule level. Our analysis suggests that Tpm1.8 decorates the two strands of the actin filament independently. Nucleation of a growing tropomyosin domain proceeds with high probability as soon as the first Tpm1.8 molecule is stabilized by the addition of a second molecule, ultimately leading to full decoration of the actin filament. In addition, Tpm1.8 domains are asymmetrical, with enhanced dynamics at the edge oriented toward the barbed end of the actin filament. The complete description of Tpm1.8 kinetics on actin filaments presented here provides molecular insight into actin-tropomyosin filament formation and the role of tropomyosins in regulating actin filament dynamics.
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Affiliation(s)
- Ilina Bareja
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Hugo Wioland
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | - Miro Janco
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Philip R. Nicovich
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Antoine Jégou
- Université de Paris, CNRS, Institut Jacques Monod, 75006 Paris, France
| | | | - James Walsh
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Till Böcking
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia
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22
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Janco M, Dedova I, Bryce NS, Hardeman EC, Gunning PW. Visualizing the in vitro assembly of tropomyosin/actin filaments using TIRF microscopy. Biophys Rev 2020; 12:879-885. [PMID: 32638329 PMCID: PMC7429660 DOI: 10.1007/s12551-020-00720-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/02/2020] [Indexed: 12/23/2022] Open
Abstract
Tropomyosins are elongated alpha-helical proteins that form co-polymers with most actin filaments within a cell and play important roles in the structural and functional diversification of the actin cytoskeleton. How the assembly of tropomyosins along an actin filament is regulated and the kinetics of tropomyosin association with an actin filament is yet to be fully determined. A recent series of publications have used total internal reflection fluorescence (TIRF) microscopy in combination with advanced surface and protein chemistry to visualise the molecular assembly of actin/tropomyosin filaments in vitro. Here, we review the use of the in vitro TIRF assay in the determination of kinetic data on tropomyosin filament assembly. This sophisticated approach has enabled generation of real-time single-molecule data to fill the gap between in vitro bulk assays and in vivo assays of tropomyosin function. The in vitro TIRF assays provide a new foundation for future studies involving multiple actin-binding proteins that will more accurately reflect the physiological protein-protein interactions in cells.
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Affiliation(s)
- Miro Janco
- School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Irina Dedova
- School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Nicole S Bryce
- School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Edna C Hardeman
- School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Peter W Gunning
- School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
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23
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Impact of the actin cytoskeleton on cell development and function mediated via tropomyosin isoforms. Semin Cell Dev Biol 2019; 102:122-131. [PMID: 31630997 DOI: 10.1016/j.semcdb.2019.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 01/07/2023]
Abstract
The physiological function of actin filaments is challenging to dissect because of the pleiotropic impact of global disruption of the actin cytoskeleton. Tropomyosin isoforms have provided a unique opportunity to address this issue. A substantial fraction of actin filaments in animal cells consist of co-polymers of actin with specific tropomyosin isoforms which determine the functional capacity of the filament. Genetic manipulation of the tropomyosins has revealed isoform specific roles and identified the physiological function of the different actin filament types based on their tropomyosin isoform composition. Surprisingly, there is remarkably little redundancy between the tropomyosins resulting in highly penetrant impacts of both ectopic overexpression and knockout of isoforms. The physiological roles of the tropomyosins cover a broad range from development and morphogenesis to cell migration and specialised tissue function and human diseases.
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24
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Zhao X, Jiang M, Wang Z. TPM4 promotes cell migration by modulating F-actin formation in lung cancer. Onco Targets Ther 2019; 12:4055-4063. [PMID: 31239699 PMCID: PMC6554522 DOI: 10.2147/ott.s198542] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/08/2019] [Indexed: 12/29/2022] Open
Abstract
Background: Tropomyosin 4 (TPM4) is a member of the tropomyosin family of actin-binding proteins. Abnormal level of TPM4 is found in several cancers, and TPM4 is considered as a potential detecting marker for ovarian cancer, breast cancer, colon cancer, keratoacanthoma and esophageal squamous cell carcinoma. In this paper, the function of TPM4 in lung cancer cell lines was determined. Materials and methods: TPM4 knockout cells were constructed by CRISPR/CAS9 technique. TPM4 overexpression cells were also constructed based on TPM4 knockout cells. Cell growth ability was detected by MTS assay. The potency of cell motility was investigated using transwell assay and wound scratch assay. The protein levels in lung cancer cells were determined by western-blot. Immunofluorescence technique was used to image the structure of F-actin. Results: As a result, TPM4 downregulation and TPM4 upregulation cell models were obtained successfully. Cell motility was inhibited by the suppression of TPM4 while cell migration was enhanced in TPM4 upregulated cells. But TPM4 was not involved in cell proliferation and EMT progression. Microfilaments were depolymerized result from the suppression of TPM4 expression. And F-actin assembly was increased when TPM4 was upregulated. Conclusion: In summary, TPM4 was able to promote cell motility by altering the actin cytoskeleton directly.
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Affiliation(s)
- Xiaoting Zhao
- Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University /Beijing Tuberculosis and Thoracic Tumor Research Institute, Tongzhou, Beijing, People's Republic of China
| | - Mei Jiang
- Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University /Beijing Tuberculosis and Thoracic Tumor Research Institute, Tongzhou, Beijing, People's Republic of China
| | - Ziyu Wang
- Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University /Beijing Tuberculosis and Thoracic Tumor Research Institute, Tongzhou, Beijing, People's Republic of China
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25
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Nefedova VV, Marchenko MA, Kleymenov SY, Datskevich PN, Levitsky DI, Matyushenko AM. Thermal unfolding of various human non-muscle isoforms of tropomyosin. Biochem Biophys Res Commun 2019; 514:613-617. [PMID: 31072616 DOI: 10.1016/j.bbrc.2019.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 05/01/2019] [Indexed: 12/25/2022]
Abstract
Tropomyosin (Tpm) is an α-helical coiled-coil protein dimer, which forms a continuous head-to-tail polymer along the actin filament. In striated muscles, Tpm plays an important role in the Ca2+-dependent regulation of muscle contraction. However, little is known about functional and especially structural properties of the numerous non-muscle Tpm isoforms. In the present work, we have applied circular dichroism (CD) and differential scanning calorimetry (DSC) to investigate thermal unfolding and domain structure of various non-muscle human Tpm isoforms. These isoforms, the products of two different genes, TPM1 and TPM3, also significantly differ by alternatively spliced exons: N-terminal exons 1a2b or 1b, internal exons 6a or 6b, and C-terminal exons 9a, 9c or 9d. Our results clearly demonstrate that structural properties of various non-muscle Tpm isoforms can be quite different depending on the presence of different alternatively spliced exons in their genes. These data show for the first time a significant difference in the thermal unfolding between muscle and non-muscle Tpm isoforms and indicate that replacement of alternatively spliced exons alters the stability of certain domains in the Tpm molecule.
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Affiliation(s)
- Victoria V Nefedova
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Marina A Marchenko
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia; Department of Biochemistry, School of Biology, Moscow State University, Moscow, 119234, Russia
| | - Sergey Y Kleymenov
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia; Koltzov Institute of Developmental Biology of the Russian Academy of Sciences, Moscow, 119334, Russia
| | - Petr N Datskevich
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia
| | - Dmitrii I Levitsky
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia; A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119234, Russia
| | - Alexander M Matyushenko
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia.
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26
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Meiring JCM, Bryce NS, Niño JLG, Gabriel A, Tay SS, Hardeman EC, Biro M, Gunning PW. Tropomyosin concentration but not formin nucleators mDia1 and mDia3 determines the level of tropomyosin incorporation into actin filaments. Sci Rep 2019; 9:6504. [PMID: 31019238 PMCID: PMC6482184 DOI: 10.1038/s41598-019-42977-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/11/2019] [Indexed: 12/31/2022] Open
Abstract
The majority of actin filaments in human cells exist as a co-polymer with tropomyosin, which determines the functionality of actin filaments in an isoform dependent manner. Tropomyosin isoforms are sorted to different actin filament populations and in yeast this process is determined by formins, however it remains unclear what process determines tropomyosin isoform sorting in mammalian cells. We have tested the roles of two major formin nucleators, mDia1 and mDia3, in the recruitment of specific tropomyosin isoforms in mammals. Despite observing poorer cell-cell attachments in mDia1 and mDia3 KD cells and an actin bundle organisation defect with mDia1 knock down; depletion of mDia1 and mDia3 individually and concurrently did not result in any significant impact on tropomyosin recruitment to actin filaments, as observed via immunofluorescence and measured via biochemical assays. Conversely, in the presence of excess Tpm3.1, the absolute amount of Tpm3.1-containing actin filaments is not fixed by actin filament nucleators but rather depends on the cell concentration of Tpm3.1. We conclude that mDia1 and mDia3 are not essential for tropomyosin recruitment and that tropomyosin incorporation into actin filaments is concentration dependent.
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Affiliation(s)
- Joyce C M Meiring
- Cellular and Genetic Medicine Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Nicole S Bryce
- Cellular and Genetic Medicine Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Jorge Luis Galeano Niño
- Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Antje Gabriel
- Cellular and Genetic Medicine Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.,Pharmaceutical Biology, Center for Drug Research, Ludwig-Maximilians-Universität, Munich, Germany
| | - Szun S Tay
- Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Edna C Hardeman
- Cellular and Genetic Medicine Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Maté Biro
- Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Peter W Gunning
- Cellular and Genetic Medicine Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
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27
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Sao K, Jones TM, Doyle AD, Maity D, Schevzov G, Chen Y, Gunning PW, Petrie RJ. Myosin II governs intracellular pressure and traction by distinct tropomyosin-dependent mechanisms. Mol Biol Cell 2019; 30:1170-1181. [PMID: 30865560 PMCID: PMC6724525 DOI: 10.1091/mbc.e18-06-0355] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Two-dimensional (2D) substrate rigidity promotes myosin II activity to increase traction force in a process negatively regulated by tropomyosin (Tpm) 2.1. We recently discovered that actomyosin contractility can increase intracellular pressure and switch tumor cells from low-pressure lamellipodia to high-pressure lobopodial protrusions during three-dimensional (3D) migration. However, it remains unclear whether these myosin II–generated cellular forces are produced simultaneously, and by the same molecular machinery. Here we identify Tpm 1.6 as a positive regulator of intracellular pressure and confirm that Tpm 2.1 is a negative regulator of traction force. We find that Tpm 1.6 and 2.1 can control intracellular pressure and traction independently, suggesting these myosin II–dependent forces are generated by distinct mechanisms. Further, these tropomyosin-regulated mechanisms can be integrated to control complex cell behaviors on 2D and in 3D environments.
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Affiliation(s)
- Kimheak Sao
- Department of Biology, Drexel University, Philadelphia, PA 19104
| | - Tia M Jones
- Department of Biology, Drexel University, Philadelphia, PA 19104
| | - Andrew D Doyle
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
| | - Debonil Maity
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Galina Schevzov
- School of Medical Sciences, University of New South Wales, Sydney NSW 2052, Australia
| | - Yun Chen
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Peter W Gunning
- School of Medical Sciences, University of New South Wales, Sydney NSW 2052, Australia
| | - Ryan J Petrie
- Department of Biology, Drexel University, Philadelphia, PA 19104
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28
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Humayun-Zakaria N, Arnold R, Goel A, Ward D, Savill S, Bryan RT. Tropomyosins: Potential Biomarkers for Urothelial Bladder Cancer. Int J Mol Sci 2019; 20:E1102. [PMID: 30836651 PMCID: PMC6429115 DOI: 10.3390/ijms20051102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 02/07/2023] Open
Abstract
Despite the incidence and prevalence of urothelial bladder cancer (UBC), few advances in treatment and diagnosis have been made in recent years. In this review, we discuss potential biomarker candidates: the tropomyosin family of genes, encoded by four loci in the human genome. The expression of these genes is tissue-specific. Tropomyosins are responsible for diverse cellular roles, most notably based upon their interplay with actin to maintain cellular processes, integrity and structure. Tropomyosins exhibit a large variety of splice forms, and altered isoform expression levels have been associated with cancer, including UBC. Notably, tropomyosin isoforms are detectable in urine, offering the potential for non-invasive diagnosis and risk-stratification. This review collates the basic knowledge on tropomyosin and its isoforms, and discusses their relationships with cancer-related phenomena, most specifically in UBC.
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Affiliation(s)
- Nada Humayun-Zakaria
- Institute of Cancer and Genomic Sciences, College of Medicine and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Roland Arnold
- Institute of Cancer and Genomic Sciences, College of Medicine and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Anshita Goel
- Institute of Cancer and Genomic Sciences, College of Medicine and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Douglas Ward
- Institute of Cancer and Genomic Sciences, College of Medicine and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Stuart Savill
- North Wales Clinical Research Centre, Betsi Cadwaladr University Health Board, Wrexham LL13 7YP, UK.
| | - Richard T Bryan
- Institute of Cancer and Genomic Sciences, College of Medicine and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
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29
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Jansen S, Goode BL. Tropomyosin isoforms differentially tune actin filament length and disassembly. Mol Biol Cell 2019; 30:671-679. [PMID: 30650006 PMCID: PMC6589703 DOI: 10.1091/mbc.e18-12-0815] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cellular actin networks exhibit diverse filamentous architectures and turnover dynamics, but how these differences are specified remains poorly understood. Here, we used multicolor total internal reflection fluorescence microscopy to ask how decoration of actin filaments by five biologically prominent Tropomyosin (TPM) isoforms influences disassembly induced by Cofilin alone, or by the collaborative effects of Cofilin, Coronin, and AIP1 (CCA). TPM decoration restricted Cofilin binding to pointed ends, while not interfering with Coronin binding to filament sides. Different isoforms of TPM provided variable levels of protection against disassembly, with the strongest protection by Tpm3.1 and the weakest by Tpm1.6. In biomimetic assays in which filaments were simultaneously assembled by formins and disassembled by CCA, these TPM isoform-specific effects persisted, giving rise to filaments with different lengths and treadmilling behavior. Together, our data reveal that TPM isoforms have quantitatively distinct abilities to tune actin filament length and turnover.
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Affiliation(s)
- Silvia Jansen
- Department of Cell Biology and Physiology, Washington University in St. Louis, St. Louis, MO 63110
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454
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30
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A Novel Actin Binding Drug with In Vivo Efficacy. Antimicrob Agents Chemother 2018; 63:AAC.01585-18. [PMID: 30323040 PMCID: PMC6325233 DOI: 10.1128/aac.01585-18] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/26/2018] [Indexed: 11/23/2022] Open
Abstract
Occidiofungin is produced by the soil bacterium Burkolderia contaminans MS14 and is structurally similar or identical to the burkholdines, xylocandins, and cepacidines. This study identified the primary cellular target of occidiofungin, which was determined to be actin. Occidiofungin is produced by the soil bacterium Burkolderia contaminans MS14 and is structurally similar or identical to the burkholdines, xylocandins, and cepacidines. This study identified the primary cellular target of occidiofungin, which was determined to be actin. The modification of occidiofungin with a functional alkyne group enabled affinity purification assays and localization studies in yeast. Occidiofungin has a subtle effect on actin dynamics that triggers apoptotic cell death. We demonstrate the highly specific localization of occidiofungin to cellular regions rich in actin in yeast and the binding of occidiofungin to purified actin in vitro. Furthermore, a disruption of actin-mediated cellular processes, such as endocytosis, nuclear segregation, and hyphal formation, was observed. All of these processes require the formation of stable actin cables, which are disrupted following the addition of a subinhibitory concentration of occidiofungin. We were also able to demonstrate the effectiveness of occidiofungin in treating a vulvovaginal yeast infection in a murine model. The results of this study are important for the development of an efficacious novel class of actin binding drugs that may fill the existing gap in treatment options for fungal infections or different types of cancer.
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31
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Janco M, Böcking T, He S, Coster ACF. Interactions of tropomyosin Tpm1.1 on a single actin filament: A method for extraction and processing of high resolution TIRF microscopy data. PLoS One 2018; 13:e0208586. [PMID: 30532204 PMCID: PMC6287813 DOI: 10.1371/journal.pone.0208586] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 11/20/2018] [Indexed: 12/14/2022] Open
Abstract
Skeletal muscle tropomyosin (Tpm1.1) is an elongated, rod-shaped, alpha-helical coiled-coil protein that forms continuous head-to-tail polymers along both sides of the actin filament. In this study we use single molecule fluorescence TIRF microscopy combined with a microfluidic device and fluorescently labelled proteins to measure Tpm1.1 association to and dissociation from single actin filaments. Our experimental setup allows us to clearly resolve Tpm1.1 interactions on both sides of the filaments. Here we provide a semi-automated method for the extraction and quantification of kymograph data for individual actin filaments bound at different Tpm1.1 concentrations. We determine boundaries on the kymograph on each side of the actin filament, based on intensity thresholding, performing fine manual editing of the boundaries (if needed) and extracting user defined kinetic properties of the system. Using our analytical tools we can determine (i) nucleation point(s) and rates, (ii) elongation rates of Tpm1.1, (iii) identify meeting points after the saturation of filament, and when dissociation occurs, (iv) initiation point(s), (v) the final dissociation point(s), as well as (vi) dissociation rates. All of these measurements can be extracted from both sides of the filament, allowing for the determination of possible differences in behaviour on the two sides of the filament, and across concentrations. The robust and repeatable nature of the method allows quantitative, semi-automated analyses to be made of large studies of acto-tropomyosin interactions, as well as for other actin binding proteins or filamentous structures, opening the way for dissection of the dynamics underlying these interactions.
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Affiliation(s)
- Miro Janco
- Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, New South Wales, Australia
| | - Till Böcking
- Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, New South Wales, Australia
| | - Stanley He
- School of Mathematics & Statistics, University of New South Wales, Sydney, New South Wales, Australia
| | - Adelle C. F. Coster
- School of Mathematics & Statistics, University of New South Wales, Sydney, New South Wales, Australia
- * E-mail:
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32
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Cheng C, Nowak RB, Amadeo MB, Biswas SK, Lo WK, Fowler VM. Tropomyosin 3.5 protects the F-actin networks required for tissue biomechanical properties. J Cell Sci 2018; 131:jcs222042. [PMID: 30333143 PMCID: PMC6288072 DOI: 10.1242/jcs.222042] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/09/2018] [Indexed: 12/20/2022] Open
Abstract
Tropomyosins (Tpms) stabilize F-actin and regulate interactions with other actin-binding proteins. The eye lens changes shape in order to focus light to transmit a clear image, and thus lens organ function is tied to its biomechanical properties, presenting an opportunity to study Tpm functions in tissue mechanics. Mouse lenses contain Tpm3.5 (also known as TM5NM5), a previously unstudied isoform encoded by Tpm3, which is associated with F-actin on lens fiber cell membranes. Decreased levels of Tpm3.5 lead to softer and less mechanically resilient lenses that are unable to resume their original shape after compression. While cell organization and morphology appear unaffected, Tmod1 dissociates from the membrane in Tpm3.5-deficient lens fiber cells resulting in reorganization of the spectrin-F-actin and α-actinin-F-actin networks at the membrane. These rearranged F-actin networks appear to be less able to support mechanical load and resilience, leading to an overall change in tissue mechanical properties. This is the first in vivo evidence that a Tpm protein is essential for cell biomechanical stability in a load-bearing non-muscle tissue, and indicates that Tpm3.5 protects mechanically stable, load-bearing F-actin in vivoThis article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Catherine Cheng
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Roberta B Nowak
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michael B Amadeo
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sondip K Biswas
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA 30314, USA
| | - Woo-Kuen Lo
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA 30314, USA
| | - Velia M Fowler
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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33
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Stefen H, Hassanzadeh-Barforoushi A, Brettle M, Fok S, Suchowerska AK, Tedla N, Barber T, Warkiani ME, Fath T. A Novel Microfluidic Device-Based Neurite Outgrowth Inhibition Assay Reveals the Neurite Outgrowth-Promoting Activity of Tropomyosin Tpm3.1 in Hippocampal Neurons. Cell Mol Neurobiol 2018; 38:1557-1563. [PMID: 30218404 DOI: 10.1007/s10571-018-0620-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/06/2018] [Indexed: 11/28/2022]
Abstract
Overcoming neurite inhibition is integral for restoring neuronal connectivity after CNS injury. Actin dynamics are critical for neurite growth cone formation and extension. The tropomyosin family of proteins is a regarded as master regulator of actin dynamics. This study investigates tropomyosin isoform 3.1 (Tpm3.1) as a potential candidate for overcoming an inhibitory substrate, as it is known to influence neurite branching and outgrowth. We designed a microfluidic device that enables neurons to be grown adjacent to an inhibitory substrate, Nogo-66. Results show that neurons, overexpressing hTpm3.1, have an increased propensity to overcome Nogo-66 inhibition. We propose Tpm3.1 as a potential target for promoting neurite growth in an inhibitory environment in the central nervous system.
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Affiliation(s)
- Holly Stefen
- Neurodegenerative and Repair Unit, School of Medical Science, UNSW Sydney, Sydney, NSW, Australia.,Neuron Culture Core Facility (NCCF), University of New South Wales, Sydney, NSW, Australia
| | - Amin Hassanzadeh-Barforoushi
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.,Cancer Division, Garvan Institute of Medical Research/The Kinghorn Cancer Centre, Sydney, NSW, 2010, Australia
| | - Merryn Brettle
- Neurodegenerative and Repair Unit, School of Medical Science, UNSW Sydney, Sydney, NSW, Australia
| | - Sandra Fok
- Neurodegenerative and Repair Unit, School of Medical Science, UNSW Sydney, Sydney, NSW, Australia
| | - Alexandra K Suchowerska
- Neurodegenerative and Repair Unit, School of Medical Science, UNSW Sydney, Sydney, NSW, Australia
| | - Nicodemus Tedla
- Inflammation Research, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Tracie Barber
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Majid Ebrahimi Warkiani
- School of Biomedical Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia. .,Institute of Molecular Medicine, Sechenov First Moscow State University, Moscow, 119991, Russia.
| | - Thomas Fath
- Neurodegenerative and Repair Unit, School of Medical Science, UNSW Sydney, Sydney, NSW, Australia. .,Neuron Culture Core Facility (NCCF), University of New South Wales, Sydney, NSW, Australia. .,Faculty of Medicine and Health Sciences, Dementia Research Centre, Macquarie University, Sydney, NSW, 2019, Australia.
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34
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Meiring JC, Bryce NS, Wang Y, Taft MH, Manstein DJ, Liu Lau S, Stear J, Hardeman EC, Gunning PW. Co-polymers of Actin and Tropomyosin Account for a Major Fraction of the Human Actin Cytoskeleton. Curr Biol 2018; 28:2331-2337.e5. [DOI: 10.1016/j.cub.2018.05.053] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/20/2018] [Accepted: 05/17/2018] [Indexed: 01/14/2023]
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35
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Nakka K, Ghigna C, Gabellini D, Dilworth FJ. Diversification of the muscle proteome through alternative splicing. Skelet Muscle 2018; 8:8. [PMID: 29510724 PMCID: PMC5840707 DOI: 10.1186/s13395-018-0152-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/15/2018] [Indexed: 12/16/2022] Open
Abstract
Background Skeletal muscles express a highly specialized proteome that allows the metabolism of energy sources to mediate myofiber contraction. This muscle-specific proteome is partially derived through the muscle-specific transcription of a subset of genes. Surprisingly, RNA sequencing technologies have also revealed a significant role for muscle-specific alternative splicing in generating protein isoforms that give specialized function to the muscle proteome. Main body In this review, we discuss the current knowledge with respect to the mechanisms that allow pre-mRNA transcripts to undergo muscle-specific alternative splicing while identifying some of the key trans-acting splicing factors essential to the process. The importance of specific splicing events to specialized muscle function is presented along with examples in which dysregulated splicing contributes to myopathies. Though there is now an appreciation that alternative splicing is a major contributor to proteome diversification, the emergence of improved “targeted” proteomic methodologies for detection of specific protein isoforms will soon allow us to better appreciate the extent to which alternative splicing modifies the activity of proteins (and their ability to interact with other proteins) in the skeletal muscle. In addition, we highlight a continued need to better explore the signaling pathways that contribute to the temporal control of trans-acting splicing factor activity to ensure specific protein isoforms are expressed in the proper cellular context. Conclusions An understanding of the signal-dependent and signal-independent events driving muscle-specific alternative splicing has the potential to provide us with novel therapeutic strategies to treat different myopathies. Electronic supplementary material The online version of this article (10.1186/s13395-018-0152-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kiran Nakka
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Claudia Ghigna
- Istituto di Genetica Molecolare-Consiglio Nazionale delle Ricerche (IGM-CNR), Pavia, Italy
| | - Davide Gabellini
- Unit of Gene Expression and Muscular Dystrophy, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, DIBIT2, 5A3-44, via Olgettina 58, 20132, Milan, Italy.
| | - F Jeffrey Dilworth
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada. .,Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, 501 Smyth Rd, Mailbox 511, Ottawa, ON, K1H 8L6, Canada.
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36
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Shaw AE, Bamburg JR. Peptide regulation of cofilin activity in the CNS: A novel therapeutic approach for treatment of multiple neurological disorders. Pharmacol Ther 2017; 175:17-27. [PMID: 28232023 PMCID: PMC5466456 DOI: 10.1016/j.pharmthera.2017.02.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cofilin is a ubiquitous protein which cooperates with many other actin-binding proteins in regulating actin dynamics. Cofilin has essential functions in nervous system development including neuritogenesis, neurite elongation, growth cone pathfinding, dendritic spine formation, and the regulation of neurotransmission and spine function, components of synaptic plasticity essential for learning and memory. Cofilin's phosphoregulation is a downstream target of many transmembrane signaling processes, and its misregulation in neurons has been linked in rodent models to many different neurodegenerative and neurological disorders including Alzheimer disease (AD), aggression due to neonatal isolation, autism, manic/bipolar disorder, and sleep deprivation. Cognitive and behavioral deficits of these rodent models have been largely abrogated by modulation of cofilin activity using viral-mediated, genetic, and/or small molecule or peptide therapeutic approaches. Neuropathic pain in rats from sciatic nerve compression has also been reduced by modulating the cofilin pathway within neurons of the dorsal root ganglia. Neuroinflammation, which occurs following cerebral ischemia/reperfusion, but which also accompanies many other neurodegenerative syndromes, is markedly reduced by peptides targeting specific chemokine receptors, which also modulate cofilin activity. Thus, peptide therapeutics offer potential for cost-effective treatment of a wide variety of neurological disorders. Here we discuss some recent results from rodent models using therapeutic peptides with a surprising ability to cross the rodent blood brain barrier and alter cofilin activity in brain. We also offer suggestions as to how neuronal-specific cofilin regulation might be achieved.
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Affiliation(s)
- Alisa E Shaw
- Department of Biochemistry and Molecular Biology, Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523-1870, United States
| | - James R Bamburg
- Department of Biochemistry and Molecular Biology, Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523-1870, United States.
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37
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Khaitlina S, Tsaplina O, Hinssen H. Cooperative effects of tropomyosin on the dynamics of the actin filament. FEBS Lett 2017; 591:1884-1891. [PMID: 28555876 DOI: 10.1002/1873-3468.12700] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 05/19/2017] [Accepted: 05/22/2017] [Indexed: 12/26/2022]
Abstract
Tropomyosin (Tpm) plays an important role in regulating the organisation and functions of the actin cytoskeleton. Here, we describe a new approach to analyse the effects of Tpm on actin dynamics. Using F-actin proteolytically modified within the DNase-binding loop (ECP-actin), we show that Tpm binding almost completely suppresses the increased subunit exchange intrinsic for this F-actin. The effect is both concentration-dependent and cooperative, with half-maximal inhibition observed at about a 1 : 50 Tpm : actin ratio. Tpm decreases not only the number concentration of ECP-actin filaments, but also the rate of the filament subunit exchange. Our data suggest that Tpm regulates the dynamics of actin filaments by an allosteric strengthening of intermonomer contacts in the actin filament, and that this mechanism may be involved in the modulation of cytoskeletal dynamics.
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Affiliation(s)
| | | | - Horst Hinssen
- Faculty of Biology, University of Bielefeld, Bielefeld, Germany
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38
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Gray KT, Kostyukova AS, Fath T. Actin regulation by tropomodulin and tropomyosin in neuronal morphogenesis and function. Mol Cell Neurosci 2017; 84:48-57. [PMID: 28433463 DOI: 10.1016/j.mcn.2017.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 04/06/2017] [Accepted: 04/11/2017] [Indexed: 12/26/2022] Open
Abstract
Actin is a profoundly influential protein; it impacts, among other processes, membrane morphology, cellular motility, and vesicle transport. Actin can polymerize into long filaments that push on membranes and provide support for intracellular transport. Actin filaments have polar ends: the fast-growing (barbed) end and the slow-growing (pointed) end. Depolymerization from the pointed end supplies monomers for further polymerization at the barbed end. Tropomodulins (Tmods) cap pointed ends by binding onto actin and tropomyosins (Tpms). Tmods and Tpms have been shown to regulate many cellular processes; however, very few studies have investigated their joint role in the nervous system. Recent data directly indicate that they can modulate neuronal morphology. Additional studies suggest that Tmod and Tpm impact molecular processes influential in synaptic signaling. To facilitate future research regarding their joint role in actin regulation in the nervous system, we will comprehensively discuss Tpm and Tmod and their known functions within molecular systems that influence neuronal development.
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Affiliation(s)
- Kevin T Gray
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, United States; School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Alla S Kostyukova
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, United States.
| | - Thomas Fath
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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39
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Gateva G, Kremneva E, Reindl T, Kotila T, Kogan K, Gressin L, Gunning PW, Manstein DJ, Michelot A, Lappalainen P. Tropomyosin Isoforms Specify Functionally Distinct Actin Filament Populations In Vitro. Curr Biol 2017; 27:705-713. [PMID: 28216317 PMCID: PMC5344678 DOI: 10.1016/j.cub.2017.01.018] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/14/2016] [Accepted: 01/10/2017] [Indexed: 12/28/2022]
Abstract
Actin filaments assemble into a variety of networks to provide force for diverse cellular processes [1]. Tropomyosins are coiled-coil dimers that form head-to-tail polymers along actin filaments and regulate interactions of other proteins, including actin-depolymerizing factor (ADF)/cofilins and myosins, with actin [2, 3, 4, 5]. In mammals, >40 tropomyosin isoforms can be generated through alternative splicing from four tropomyosin genes. Different isoforms display non-redundant functions and partially non-overlapping localization patterns, for example within the stress fiber network [6, 7]. Based on cell biological studies, it was thus proposed that tropomyosin isoforms may specify the functional properties of different actin filament populations [2]. To test this hypothesis, we analyzed the properties of actin filaments decorated by stress-fiber-associated tropomyosins (Tpm1.6, Tpm1.7, Tpm2.1, Tpm3.1, Tpm3.2, and Tpm4.2). These proteins bound F-actin with high affinity and competed with α-actinin for actin filament binding. Importantly, total internal reflection fluorescence (TIRF) microscopy of fluorescently tagged proteins revealed that most tropomyosin isoforms cannot co-polymerize with each other on actin filaments. These isoforms also bind actin with different dynamics, which correlate with their effects on actin-binding proteins. The long isoforms Tpm1.6 and Tpm1.7 displayed stable interactions with actin filaments and protected filaments from ADF/cofilin-mediated disassembly, but did not activate non-muscle myosin IIa (NMIIa). In contrast, the short isoforms Tpm3.1, Tpm3.2, and Tpm4.2 displayed rapid dynamics on actin filaments and stimulated the ATPase activity of NMIIa, but did not efficiently protect filaments from ADF/cofilin. Together, these data provide experimental evidence that tropomyosin isoforms segregate to different actin filaments and specify functional properties of distinct actin filament populations. Stress-fiber-associated tropomyosin isoforms segregate to different actin filaments Tropomyosin isoforms bind F-actin with different dynamics Dynamic tropomyosin isoforms activate non-muscle myosin II Stable tropomyosin isoforms protect actin filaments from ADF/cofilin
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Affiliation(s)
- Gergana Gateva
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Elena Kremneva
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Theresia Reindl
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Tommi Kotila
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Konstantin Kogan
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Laurène Gressin
- Biosciences and Biotechnology Institute of Grenoble, LPCV/CNRS/CEA/UGA/INRA, 38054 Grenoble, France
| | - Peter W Gunning
- Oncology Research Unit, School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia
| | - Dietmar J Manstein
- Institute for Biophysical Chemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Alphée Michelot
- Aix-Marseille University, CNRS, IBDM, 13284 Marseille, France
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
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40
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Nicovich PR, Janco M, Sobey T, Gajwani M, Obeidy P, Whan R, Gaus K, Gunning PW, Coster AC, Böcking T. Effect of surface chemistry on tropomyosin binding to actin filaments on surfaces. Cytoskeleton (Hoboken) 2016; 73:729-738. [PMID: 27783462 DOI: 10.1002/cm.21342] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 01/29/2023]
Abstract
Reconstitution of actin filaments on surfaces for observation of filament-associated protein dynamics by fluorescence microscopy is currently an exciting field in biophysics. Here we examine the effects of attaching actin filaments to surfaces on the binding and dissociation kinetics of a fluorescence-labeled tropomyosin, a rod-shaped protein that forms continuous strands wrapping around the actin filament. Two attachment modalities of the actin to the surface are explored: where the actin filament is attached to the surface at multiple points along its length; and where the actin filament is attached at one end and aligned parallel to the surface by buffer flow. To facilitate analysis of actin-binding protein dynamics, we have developed a software tool for the viewing, tracing and analysis of filaments and co-localized species in noisy fluorescence timelapse images. Our analysis shows that the interaction of tropomyosin with actin filaments is similar for both attachment modalities. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Philip R Nicovich
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Miro Janco
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Tom Sobey
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Mehul Gajwani
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Peyman Obeidy
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Renee Whan
- Biomedical Imaging Facility, University of New South Wales, Sydney, Australia
| | - Katharina Gaus
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Peter W Gunning
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Adelle Cf Coster
- School of Mathematics and Statistics, University of New South Wales, Sydney, Australia
| | - Till Böcking
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
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