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Chiang WY, Yu HW, Wu MC, Huang YM, Chen YQ, Lin JW, Liu YW, You LR, Chiou A, Kuo JC. Matrix mechanics regulates muscle regeneration by modulating kinesin-1 activity. Biomaterials 2024; 308:122551. [PMID: 38593710 DOI: 10.1016/j.biomaterials.2024.122551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/11/2024]
Abstract
Sarcopenia, a prevalent muscle disease characterized by muscle mass and strength reduction, is associated with impaired skeletal muscle regeneration. However, the influence of the biomechanical properties of sarcopenic skeletal muscle on the efficiency of the myogenic program remains unclear. Herein, we established a mouse model of sarcopenia and observed a reduction in stiffness within the sarcopenic skeletal muscle in vivo. To investigate whether the biomechanical properties of skeletal muscle directly impact the myogenic program, we established an in vitro system to explore the intrinsic mechanism involving matrix stiffness control of myogenic differentiation. Our findings identify the microtubule motor protein, kinesin-1, as a mechano-transduction hub that senses and responds to matrix stiffness, crucial for myogenic differentiation and muscle regeneration. Specifically, kinesin-1 activity is positively regulated by stiff matrices, facilitating its role in transporting mitochondria and enhancing translocation of the glucose transporter GLUT4 to the cell surface for glucose uptake. Conversely, the softer matrices significantly suppress kinesin-1 activity, leading to the accumulation of mitochondria around nuclei and hindering glucose uptake by inhibiting GLUT4 membrane translocation, consequently impairing myogenic differentiation. The insights gained from the in-vitro system highlight the mechano-transduction significance of kinesin-1 motor proteins in myogenic differentiation. Furthermore, our study confirms that enhancing kinesin-1 activity in the sarcopenic mouse model restores satellite cell expansion, myogenic differentiation, and muscle regeneration. Taken together, our findings provide a potential target for improving muscle regeneration in sarcopenia.
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Affiliation(s)
- Wan-Yu Chiang
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Helen Wenshin Yu
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Ming-Chung Wu
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Yi-Man Huang
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Yin-Quan Chen
- Cancer and Immunology Research Center, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Jong-Wei Lin
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Yen-Wenn Liu
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Li-Ru You
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Arthur Chiou
- Institute of Biophotonics, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan
| | - Jean-Cheng Kuo
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan; Cancer and Immunology Research Center, National Yang Ming Chiao Tung University, Taipei, 11221, Taiwan.
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Nguyen MT, Ly QK, Kim HJ, Lee W. WAVE2 Is a Vital Regulator in Myogenic Differentiation of Progenitor Cells through the Mechanosensitive MRTFA-SRF Axis. Cells 2023; 13:9. [PMID: 38201213 PMCID: PMC10778525 DOI: 10.3390/cells13010009] [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: 11/17/2023] [Revised: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024] Open
Abstract
Skeletal myogenesis is an intricate process involving the differentiation of progenitor cells into myofibers, which is regulated by actin cytoskeletal dynamics and myogenic transcription factors. Although recent studies have demonstrated the pivotal roles of actin-binding proteins (ABPs) as mechanosensors and signal transducers, the biological significance of WAVE2 (Wiskott-Aldrich syndrome protein family member 2), an ABP essential for actin polymerization, in myogenic differentiation of progenitor cells has not been investigated. Our study provides important insights into the regulatory roles played by WAVE2 in the myocardin-related transcription factor A (MRTFA)-serum response factor (SRF) signaling axis and differentiation of myoblasts. We demonstrate that WAVE2 expression is induced during myogenic differentiation and plays a pivotal role in actin cytoskeletal remodeling in C2C12 myoblasts. Knockdown of WAVE2 in C2C12 cells reduced filamentous actin levels, increased globular actin accumulation, and impaired the nuclear translocation of MRTFA. Furthermore, WAVE2 depletion in myoblasts inhibited the expression and transcriptional activity of SRF and suppressed cell proliferation in myoblasts. Consequently, WAVE2 knockdown suppressed myogenic regulatory factors (i.e., MyoD, MyoG, and SMYD1) expressions, thereby hindering the differentiation of myoblasts. Thus, this study suggests that WAVE2 is essential for myogenic differentiation of progenitor cells by modulating the mechanosensitive MRTFA-SRF axis.
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Affiliation(s)
- Mai Thi Nguyen
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
| | - Quoc Kiet Ly
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
| | - Hyun-Jung Kim
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
| | - Wan Lee
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
- Channelopathy Research Center, Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Republic of Korea
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3
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Cooper A, Makkay AM, Papke RT. Archaeal Tubulin-like Proteins Modify Cell Shape in Haloferax volcanii during Early Biofilm Development. Genes (Basel) 2023; 14:1861. [PMID: 37895209 PMCID: PMC10606840 DOI: 10.3390/genes14101861] [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: 08/01/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 10/29/2023] Open
Abstract
Tubulin, an extensively studied self-assembling protein, forms filaments in eukaryotic cells that affect cell shape, among other functions. The model archaeon Haloferax volcanii uses two tubulin-like proteins (FtsZ1/FtsZ2) for cell division, similar to bacteria, but has an additional six related tubulins called CetZ. One of them, CetZ1, was shown to play a role in cell shape. Typically, discoid and rod shapes are observed in planktonic growth, but under biofilm formation conditions (i.e., attached to a substratum), H. volcanii can grow filamentously. Here, we show that the deletion mutants of all eight tubulin-like genes significantly impacted morphology when cells were allowed to form a biofilm. ΔftsZ1, ΔcetZ2, and ΔcetZ4-6 created longer, less round cells than the parental and a higher percentage of filaments. ΔcetZ1 and ΔcetZ3 were significantly rounder than the parental, and ΔftsZ2 generated larger, flat, amorphic cells. The results show all tubulin homologs affect morphology at most timepoints, which therefore suggests these genes indeed have a function.
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Affiliation(s)
| | | | - R. Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06268, USA; (A.C.); (A.M.M.)
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Nguyen MT, Ly QK, Kim HJ, Lee W. FLII Modulates the Myogenic Differentiation of Progenitor Cells via Actin Remodeling-Mediated YAP1 Regulation. Int J Mol Sci 2023; 24:14335. [PMID: 37762638 PMCID: PMC10531566 DOI: 10.3390/ijms241814335] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 09/16/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
The dynamic rearrangement of the actin cytoskeleton plays an essential role in myogenesis, which is regulated by diverse mechanisms, such as mechanotransduction, modulation of the Hippo signaling pathway, control of cell proliferation, and the influence of morphological changes. Despite the recognized importance of actin-binding protein Flightless-1 (FLII) during actin remodeling, the role played by FLII in the differentiation of myogenic progenitor cells has not been explored. Here, we investigated the roles of FLII in the proliferation and differentiation of myoblasts. FLII was found to be enriched in C2C12 myoblasts, and its expression was stable during the early stages of differentiation but down-regulated in fully differentiated myotubes. Knockdown of FLII in C2C12 myoblasts resulted in filamentous actin (F-actin) accumulation and inhibited Yes-associated protein 1 (YAP1) phosphorylation, which triggers its nuclear translocation from the cytoplasm. Consequently, the expressions of YAP1 target genes, including PCNA, CCNB1, and CCND1, were induced, and the cell cycle and proliferation of myoblasts were promoted. Moreover, FLII knockdown significantly inhibited the expression of myogenic regulatory factors, i.e., MyoD and MyoG, thereby impairing myoblast differentiation, fusion, and myotube formation. Thus, our findings demonstrate that FLII is crucial for the differentiation of myoblasts via modulation of the F-actin/YAP1 axis and suggest that FLII is a putative novel therapeutic target for muscle wasting.
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Affiliation(s)
- Mai Thi Nguyen
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
| | - Quoc Kiet Ly
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
| | - Hyun-Jung Kim
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
| | - Wan Lee
- Department of Biochemistry, Dongguk University College of Medicine, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea; (M.T.N.); (Q.K.L.); (H.-J.K.)
- Channelopathy Research Center, Dongguk University College of Medicine, 32 Dongguk-ro, Goyang 10326, Republic of Korea
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Grande V, Schuld J, van der Ven PFM, Gruss OJ, Fürst DO. Filamin-A-interacting protein 1 (FILIP1) is a dual compartment protein linking myofibrils and microtubules during myogenic differentiation and upon mechanical stress. Cell Tissue Res 2023:10.1007/s00441-023-03776-4. [PMID: 37178194 DOI: 10.1007/s00441-023-03776-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/19/2023] [Indexed: 05/15/2023]
Abstract
Variations in the gene encoding filamin-A-interacting protein 1 (FILIP1) were identified to be associated with a combination of neurological and muscular symptoms. While FILIP1 was shown to regulate motility of brain ventricular zone cells, a process important for corticogenesis, the function of the protein in muscle cells has been less well characterized. The expression of FILIP1 in regenerating muscle fibres predicted a role in early muscle differentiation. Here we analysed expression and localization of FILIP1 and its binding partners filamin-C (FLNc) and microtubule plus-end-binding protein EB3 in differentiating cultured myotubes and adult skeletal muscle. Prior to the development of cross-striated myofibrils, FILIP1 is associated with microtubules and colocalizes with EB3. During further myofibril maturation its localization changes, and FILIP1 localizes to myofibrillar Z-discs together with the actin-binding protein FLNc. Forced contractions of myotubes by electrical pulse stimulation (EPS) induce focal disruptions in myofibrils and translocation of both proteins from Z-discs to these lesions, suggesting a role in induction and/or repair of these structures. The immediate proximity of tyrosylated, dynamic microtubules and EB3 to lesions implies that also these play a role in these processes. This implication is supported by the fact that in nocodazole-treated myotubes that lack functional microtubules, the number of lesions induced by EPS is significantly reduced. In summary, we here show that FILIP1 is a cytolinker protein that is associated with both microtubules and actin filaments, and might play a role in the assembly of myofibrils and their stabilization upon mechanical stress to protect them from damage.
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Affiliation(s)
- Valentina Grande
- Institute for Cell Biology, University of Bonn, Ulrich-Haberland-Str. 61a, 53121, Bonn, Germany
| | - Julia Schuld
- Institute for Cell Biology, University of Bonn, Ulrich-Haberland-Str. 61a, 53121, Bonn, Germany
| | - Peter F M van der Ven
- Institute for Cell Biology, University of Bonn, Ulrich-Haberland-Str. 61a, 53121, Bonn, Germany
| | - Oliver J Gruss
- Institute of Genetics, University of Bonn, Karlrobert-Kreiten-Str. 13, 53115, Bonn, Germany
| | - Dieter O Fürst
- Institute for Cell Biology, University of Bonn, Ulrich-Haberland-Str. 61a, 53121, Bonn, Germany.
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6
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Lucas L, Cooper TA. Insights into Cell-Specific Functions of Microtubules in Skeletal Muscle Development and Homeostasis. Int J Mol Sci 2023; 24:ijms24032903. [PMID: 36769228 PMCID: PMC9917663 DOI: 10.3390/ijms24032903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/17/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
The contractile cells of skeletal muscles, called myofibers, are elongated multinucleated syncytia formed and maintained by the fusion of proliferative myoblasts. Human myofibers can be hundreds of microns in diameter and millimeters in length. Myofibers are non-mitotic, obviating the need for microtubules in cell division. However, microtubules have been adapted to the unique needs of these cells and are critical for myofiber development and function. Microtubules in mature myofibers are highly dynamic, and studies in several experimental systems have demonstrated the requirements for microtubules in the unique features of muscle biology including myoblast fusion, peripheral localization of nuclei, assembly of the sarcomere, transport and signaling. Microtubule-binding proteins have also been adapted to the needs of the skeletal muscle including the expression of skeletal muscle-specific protein isoforms generated by alternative splicing. Here, we will outline the different roles microtubules play in skeletal muscle cells, describe how microtubule abnormalities can lead to muscle disease and discuss the broader implications for microtubule function.
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Affiliation(s)
- Lathan Lucas
- Chemical, Physical, Structural Biology Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Thomas A. Cooper
- Chemical, Physical, Structural Biology Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
- Correspondence:
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Sakai H, Matsumoto K, Urano T, Sakane F. Myristic acid selectively augments β-tubulin levels in C2C12 myotubes via diacylglycerol kinase δ. FEBS Open Bio 2022; 12:1788-1796. [PMID: 35856166 PMCID: PMC9527581 DOI: 10.1002/2211-5463.13466] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 06/29/2022] [Accepted: 07/19/2022] [Indexed: 12/14/2022] Open
Abstract
Effective amelioration of type II diabetes requires therapies that increase both glucose uptake activity per cell and skeletal muscle mass. Myristic acid (14:0) increases diacylglycerol kinase (DGK) δ protein levels and enhances glucose uptake in myotubes in a DGKδ-dependent manner. However, it is still unclear whether myristic acid treatment affects skeletal muscle mass. In this study, we found that myristic acid treatment increased the protein level of β-tubulin, which constitutes microtubules and is closely related to muscle mass, in C2C12 myotubes but not in the proliferation stage in C2C12 myoblasts. However, lauric (12:0), palmitic (16:0) and oleic (18:1) acids failed to affect DGKδ and β-tubulin protein levels in C2C12 myotubes. Moreover, knockdown of DGKδ by siRNA significantly inhibited the increased protein level of β-tubulin in the presence of myristic acid, suggesting that the increase in β-tubulin protein by myristic acid depends on DGKδ. These results indicate that myristic acid selectively affects β-tubulin protein levels in C2C12 myotubes via DGKδ, suggesting that this fatty acid improves skeletal muscle mass in addition to increasing glucose uptake activity per cell.
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Affiliation(s)
- Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic InformationShimane UniversityIzumoJapan
| | - Ken‐ichi Matsumoto
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic InformationShimane UniversityIzumoJapan
| | - Takeshi Urano
- Department of BiochemistryShimane University School of MedicineIzumoJapan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of ScienceChiba UniversityJapan
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Datta A, Deng S, Gopal V, Yap KCH, Halim CE, Lye ML, Ong MS, Tan TZ, Sethi G, Hooi SC, Kumar AP, Yap CT. Cytoskeletal Dynamics in Epithelial-Mesenchymal Transition: Insights into Therapeutic Targets for Cancer Metastasis. Cancers (Basel) 2021; 13:cancers13081882. [PMID: 33919917 PMCID: PMC8070945 DOI: 10.3390/cancers13081882] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/08/2021] [Accepted: 04/12/2021] [Indexed: 12/14/2022] Open
Abstract
In cancer cells, a vital cellular process during metastasis is the transformation of epithelial cells towards motile mesenchymal cells called the epithelial to mesenchymal transition (EMT). The cytoskeleton is an active network of three intracellular filaments: actin cytoskeleton, microtubules, and intermediate filaments. These filaments play a central role in the structural design and cell behavior and are necessary for EMT. During EMT, epithelial cells undergo a cellular transformation as manifested by cell elongation, migration, and invasion, coordinated by actin cytoskeleton reorganization. The actin cytoskeleton is an extremely dynamic structure, controlled by a balance of assembly and disassembly of actin filaments. Actin-binding proteins regulate the process of actin polymerization and depolymerization. Microtubule reorganization also plays an important role in cell migration and polarization. Intermediate filaments are rearranged, switching to a vimentin-rich network, and this protein is used as a marker for a mesenchymal cell. Hence, targeting EMT by regulating the activities of their key components may be a potential solution to metastasis. This review summarizes the research done on the physiological functions of the cytoskeleton, its role in the EMT process, and its effect on multidrug-resistant (MDR) cancer cells-highlight some future perspectives in cancer therapy by targeting cytoskeleton.
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Affiliation(s)
- Arpita Datta
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; (A.D.); (S.D.); (V.G.); (K.C.-H.Y.); (C.E.H.); (M.L.L.); (M.S.O.); (S.C.H.)
| | - Shuo Deng
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; (A.D.); (S.D.); (V.G.); (K.C.-H.Y.); (C.E.H.); (M.L.L.); (M.S.O.); (S.C.H.)
| | - Vennila Gopal
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; (A.D.); (S.D.); (V.G.); (K.C.-H.Y.); (C.E.H.); (M.L.L.); (M.S.O.); (S.C.H.)
| | - Kenneth Chun-Hong Yap
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; (A.D.); (S.D.); (V.G.); (K.C.-H.Y.); (C.E.H.); (M.L.L.); (M.S.O.); (S.C.H.)
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore;
| | - Clarissa Esmeralda Halim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; (A.D.); (S.D.); (V.G.); (K.C.-H.Y.); (C.E.H.); (M.L.L.); (M.S.O.); (S.C.H.)
| | - Mun Leng Lye
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; (A.D.); (S.D.); (V.G.); (K.C.-H.Y.); (C.E.H.); (M.L.L.); (M.S.O.); (S.C.H.)
| | - Mei Shan Ong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; (A.D.); (S.D.); (V.G.); (K.C.-H.Y.); (C.E.H.); (M.L.L.); (M.S.O.); (S.C.H.)
| | - Tuan Zea Tan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117593, Singapore;
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore;
- Cancer Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Shing Chuan Hooi
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; (A.D.); (S.D.); (V.G.); (K.C.-H.Y.); (C.E.H.); (M.L.L.); (M.S.O.); (S.C.H.)
- Cancer Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
| | - Alan Prem Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore;
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117593, Singapore;
- Cancer Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- National University Cancer Institute, National University Health System, Singapore 119074, Singapore
- Correspondence: (A.P.K.); (C.T.Y); Tel.: +65-6873-5456 (A.P.K.); +65-6516-3294 (C.T.Y.); Fax: +65-6873-9664 (A.P.K.); +65-6778-8161 (C.T.Y.)
| | - Celestial T. Yap
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore; (A.D.); (S.D.); (V.G.); (K.C.-H.Y.); (C.E.H.); (M.L.L.); (M.S.O.); (S.C.H.)
- Cancer Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- National University Cancer Institute, National University Health System, Singapore 119074, Singapore
- Correspondence: (A.P.K.); (C.T.Y); Tel.: +65-6873-5456 (A.P.K.); +65-6516-3294 (C.T.Y.); Fax: +65-6873-9664 (A.P.K.); +65-6778-8161 (C.T.Y.)
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9
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Zhou D, Nie ZW, Cui XS. EB1 Is Essential for Spindle Formation and Chromosome Alignment During Oocyte Meiotic Maturation in Mice. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:385-391. [PMID: 33413706 DOI: 10.1017/s1431927620024897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The cytoskeleton plays an orchestrating role in polarized cell growth. Microtubules (MTs) not only play critical roles in chromosome alignment and segregation but also control cell shape, division, and motility. A member of the plus-end tracking proteins, end-binding protein 1 (EB1), regulates MT dynamics and plays vital roles in maintaining spindle symmetry and chromosome alignment during mitosis. However, the role of EB1 in mouse oocyte meiosis remains unknown. Here, we examined the localization patterns and expression levels of EB1 at different stages. EB1 protein level was found to be stable during meiosis. EB1 mainly localized along the spindle and had a similar localization pattern as that of α-tubulin. The EB1 protein was degraded with a Trim-Away method, and the results were further confirmed with western blotting and immunofluorescence. At 12 h of culture after EB1 knockdown (KD), a reduced number of mature MII oocytes were observed. EB1 KD led to spindle disorganization, chromosome misalignment, and missegregation; β-catenin protein binds to actin via the adherens junctional complex, which was significantly reduced in the EB1 KD oocytes. Collectively, we propose that the impairment of EB1 function manipulates spindle formation, thereby promoting chromosomal loss, which is expected to fuel aneuploidy and possibly fertilization failure.
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Affiliation(s)
- Dongjie Zhou
- Department of Animal Science, Chungbuk National University, 356 Room, S21-5 Dong, Chungdae-ro 1, Seowon-Gu, Cheongju, Chungbuk28644, South Korea
| | - Zheng-Wen Nie
- Department of Animal Science, Chungbuk National University, 356 Room, S21-5 Dong, Chungdae-ro 1, Seowon-Gu, Cheongju, Chungbuk28644, South Korea
| | - Xiang-Shun Cui
- Department of Animal Science, Chungbuk National University, 356 Room, S21-5 Dong, Chungdae-ro 1, Seowon-Gu, Cheongju, Chungbuk28644, South Korea
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10
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Dexamethasone accelerates muscle regeneration by modulating kinesin-1-mediated focal adhesion signals. Cell Death Discov 2021; 7:35. [PMID: 33597503 PMCID: PMC7889929 DOI: 10.1038/s41420-021-00412-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/27/2020] [Accepted: 10/30/2020] [Indexed: 01/11/2023] Open
Abstract
During differentiation, skeletal muscle develops mature multinucleated muscle fibers, which could contract to exert force on a substrate. Muscle dysfunction occurs progressively in patients with muscular dystrophy, leading to a loss of the ability to walk and eventually to death. The synthetic glucocorticoid dexamethasone (Dex) has been used therapeutically to treat muscular dystrophy by an inhibition of inflammation, followed by slowing muscle degeneration and stabilizing muscle strength. Here, in mice with muscle injury, we found that Dex significantly promotes muscle regeneration via promoting kinesin-1 motor activity. Nevertheless, how Dex promotes myogenesis through kinesin-1 motors remains unclear. We found that Dex directly increases kinesin-1 motor activity, which is required for the expression of a myogenic marker (muscle myosin heavy chain 1/2), and also for the process of myoblast fusion and the formation of polarized myotubes. Upon differentiation, kinesin-1 mediates the recruitment of integrin β1 onto microtubules allowing delivery of the protein into focal adhesions. Integrin β1-mediated focal adhesion signaling then guides myoblast fusion towards a polarized morphology. By imposing geometric constrains via micropatterns, we have proved that cell adhesion is able to rescue the defects caused by kinesin-1 inhibition during the process of myogenesis. These discoveries reveal a mechanism by which Dex is able to promote myogenesis, and lead us towards approaches that are more efficient in improving skeletal muscle regeneration.
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CFL2 is an essential mediator for myogenic differentiation in C2C12 myoblasts. Biochem Biophys Res Commun 2020; 533:710-716. [PMID: 33187645 DOI: 10.1016/j.bbrc.2020.11.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 11/05/2020] [Indexed: 12/29/2022]
Abstract
CFL2, a skeletal muscle-specific member of the actin depolymerizing factor/cofilin protein family, is known to be involved in the regulation of actin filament dynamics. Although the impact of CFL2 has been studied in human myopathy, its functional contribution to myogenic differentiation, in terms of its effects on cell proliferation, cell cycle, and myogenic factor modulation, remains largely unknown. Here, we report that CFL2 is required for the myogenic differentiation of C2C12 myoblasts by regulating proliferation and myogenic transcription factors expressions. CFL2 expression was induced during myogenic progression, and its knockdown by siRNA in myoblasts enhanced phalloidin staining, indicating increased filamentous actin formation. Interestingly, CFL2 depletion stimulated cell proliferation and induced a cell cycle shift from G0/G1 to G2/M phases, which are known to inhibit progenitor cell differentiation. CFL2 knockdown markedly downregulated the protein expressions of myogenic transcription factors (MyoD, MyoG, and MEF2C) and thereby impaired the differentiation and myotube formation of C2C12 myoblasts. Collectively, this study highlights the roles played by CFL2 on cell cycle progression and proliferation and suggests a novel regulatory mechanism of myogenic differentiation mediated by CFL2.
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12
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Nelson DM, Fasbender EK, Jakubiak MC, Lindsay A, Lowe DA, Ervasti JM. Rapid, redox-mediated mechanical susceptibility of the cortical microtubule lattice in skeletal muscle. Redox Biol 2020; 37:101730. [PMID: 33002761 PMCID: PMC7527753 DOI: 10.1016/j.redox.2020.101730] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/12/2020] [Accepted: 09/12/2020] [Indexed: 01/25/2023] Open
Abstract
The highly ordered cortical microtubule lattice of skeletal muscle is disorganized in dystrophin-deficient mdx mice. Implicated mechanisms include loss of dystrophin binding, altered α-tubulin posttranslational modification, expression of a β-tubulin involved in regeneration, and reactive oxygen species (ROS). Here we show that the transverse microtubules in mdx muscle expressing miniaturized dystrophins are rapidly lost after eccentric contraction. Analysis of mdx lines expressing different dystrophin constructs demonstrate that spectrin-like repeats R4-15 and R20-23 were required for mechanically stable microtubules. Microtubule loss was prevented by the non-specific antioxidant N-acetylcysteine while inhibition of NADPH oxidase 2 had only a partial effect, suggesting that ROS from multiple sources mediate the rapid loss of transverse microtubules after eccentric contraction. Finally, ablation of α-dystrobrevin, β- or γ-cytoplasmic actin phenocopied the transverse microtubule instability of miniaturized dystrophins. Our data demonstrate that multiple dystrophin domains, α-dystrobrevin and cytoplasmic actins are necessary for mechanically stable microtubules.
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Affiliation(s)
- D'anna M Nelson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Elizabeth K Fasbender
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Margurite C Jakubiak
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Angus Lindsay
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Dawn A Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
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13
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Sébastien M, Giannesini B, Aubin P, Brocard J, Chivet M, Pietrangelo L, Boncompagni S, Bosc C, Brocard J, Rendu J, Gory-Fauré S, Andrieux A, Fourest-Lieuvin A, Fauré J, Marty I. Deletion of the microtubule-associated protein 6 (MAP6) results in skeletal muscle dysfunction. Skelet Muscle 2018; 8:30. [PMID: 30231928 PMCID: PMC6147105 DOI: 10.1186/s13395-018-0176-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/12/2018] [Indexed: 01/23/2023] Open
Abstract
Background The skeletal muscle fiber has a specific and precise intracellular organization which is at the basis of an efficient muscle contraction. Microtubules are long known to play a major role in the function and organization of many cells, but in skeletal muscle, the contribution of the microtubule cytoskeleton to the efficiency of contraction has only recently been studied. The microtubule network is dynamic and is regulated by many microtubule-associated proteins (MAPs). In the present study, the role of the MAP6 protein in skeletal muscle organization and function has been studied using the MAP6 knockout mouse line. Methods The presence of MAP6 transcripts and proteins was shown in mouse muscle homogenates and primary culture using RT-PCR and western blot. The in vivo evaluation of muscle force of MAP6 knockout (KO) mice was performed on anesthetized animals using electrostimulation coupled to mechanical measurement and multimodal magnetic resonance. The impact of MAP6 deletion on microtubule organization and intracellular structures was studied using immunofluorescent labeling and electron microscopy, and on calcium release for muscle contraction using Fluo-4 calcium imaging on cultured myotubes. Statistical analysis was performed using Student’s t test or the Mann-Whitney test. Results We demonstrate the presence of MAP6 transcripts and proteins in skeletal muscle. Deletion of MAP6 results in a large number of muscle modifications: muscle weakness associated with slight muscle atrophy, alterations of microtubule network and sarcoplasmic reticulum organization, and reduction in calcium release. Conclusion Altogether, our results demonstrate that MAP6 is involved in skeletal muscle function. Its deletion results in alterations in skeletal muscle contraction which contribute to the global deleterious phenotype of the MAP6 KO mice. As MAP6 KO mouse line is a model for schizophrenia, our work points to a possible muscle weakness associated to some forms of schizophrenia. Electronic supplementary material The online version of this article (10.1186/s13395-018-0176-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Muriel Sébastien
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | | | - Perrine Aubin
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Julie Brocard
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Mathilde Chivet
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Laura Pietrangelo
- CeSI-Met & DNICS, University G. d' Annunzio of Chieti, I-66100, Chieti, Italy
| | - Simona Boncompagni
- CeSI-Met & DNICS, University G. d' Annunzio of Chieti, I-66100, Chieti, Italy
| | - Christophe Bosc
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Jacques Brocard
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - John Rendu
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France.,CHU Grenoble, Biochimie et Génétique Moléculaire, F-38000, Grenoble, France
| | - Sylvie Gory-Fauré
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France
| | - Annie Andrieux
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France.,CEA-Grenoble, BIG, F-38000, Grenoble, France
| | - Anne Fourest-Lieuvin
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France.,CEA-Grenoble, BIG, F-38000, Grenoble, France
| | - Julien Fauré
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France.,University Grenoble Alpes, F-38000, Grenoble, France.,CHU Grenoble, Biochimie et Génétique Moléculaire, F-38000, Grenoble, France
| | - Isabelle Marty
- INSERM 1216, Grenoble Institute of Neurosciences, F-38000, Grenoble, France. .,University Grenoble Alpes, F-38000, Grenoble, France. .,GIN- Inserm U1216 - Bat EJ Safra, Chemin Fortuné Ferrini, 38700, La Tronche, France.
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14
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Goldspink DA, Rookyard C, Tyrrell BJ, Gadsby J, Perkins J, Lund EK, Galjart N, Thomas P, Wileman T, Mogensen MM. Ninein is essential for apico-basal microtubule formation and CLIP-170 facilitates its redeployment to non-centrosomal microtubule organizing centres. Open Biol 2017; 7:rsob.160274. [PMID: 28179500 PMCID: PMC5356440 DOI: 10.1098/rsob.160274] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/17/2017] [Indexed: 01/08/2023] Open
Abstract
Differentiation of columnar epithelial cells involves a dramatic reorganization of the microtubules (MTs) and centrosomal components into an apico-basal array no longer anchored at the centrosome. Instead, the minus-ends of the MTs become anchored at apical non-centrosomal microtubule organizing centres (n-MTOCs). Formation of n-MTOCs is critical as they determine the spatial organization of MTs, which in turn influences cell shape and function. However, how they are formed is poorly understood. We have previously shown that the centrosomal anchoring protein ninein is released from the centrosome, moves in a microtubule-dependent manner and accumulates at n-MTOCs during epithelial differentiation. Here, we report using depletion and knockout (KO) approaches that ninein expression is essential for apico-basal array formation and epithelial elongation and that CLIP-170 is required for its redeployment to n-MTOCs. Functional inhibition also revealed that IQGAP1 and active Rac1 coordinate with CLIP-170 to facilitate microtubule plus-end cortical targeting and ninein redeployment. Intestinal tissue and in vitro organoids from the Clip1/Clip2 double KO mouse with deletions in the genes encoding CLIP-170 and CLIP-115, respectively, confirmed requirement of CLIP-170 for ninein recruitment to n-MTOCs, with possible compensation by other anchoring factors such as p150Glued and CAMSAP2 ensuring apico-basal microtubule formation despite loss of ninein at n-MTOCs.
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Affiliation(s)
| | - Chris Rookyard
- School of Computing Science, University of East Anglia, Norwich, UK
| | | | - Jonathan Gadsby
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - James Perkins
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - Elizabeth K Lund
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - Niels Galjart
- Department of Cell Biology and Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Paul Thomas
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - Tom Wileman
- Medical School, University of East Anglia, Norwich, UK
| | - Mette M Mogensen
- School of Biological Sciences, University of East Anglia, Norwich, UK
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15
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Gemoll T, Kollbeck SL, Karstens KF, Hò GG, Hartwig S, Strohkamp S, Schillo K, Thorns C, Oberländer M, Kalies K, Lehr S, Habermann JK. EB1 protein alteration characterizes sporadic but not ulcerative colitis associated colorectal cancer. Oncotarget 2017; 8:54939-54950. [PMID: 28903393 PMCID: PMC5589632 DOI: 10.18632/oncotarget.18978] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 06/17/2017] [Indexed: 12/29/2022] Open
Abstract
Background While carcinogenesis in Sporadic Colorectal Cancer (SCC) has been thoroughly studied, less is known about Ulcerative Colitis associated Colorectal Cancer (UCC). This study aimed to identify and validate differentially expressed proteins between clinical samples of SCC and UCC to elucidate new insights of UCC/SCC carcinogenesis and progression. Results Multiplex-fluorescence two-dimensional gel electrophoresis (2-D DIGE) and mass spectrometry identified 67 proteoforms representing 43 distinct proteins. After analysis by Ingenuity Pathway Analysis® (IPA), subsequent Western blot validation proofed the differential expression of Heat shock 27 kDA protein 1 (HSPB1) and Microtubule-associated protein R/EB family, member 1 (EB1) while the latter one showed also expression differences by immunohistochemistry. Materials and Methods Fresh frozen tissue of UCC (n = 10) matched with SCC (n = 10) was investigated. Proteins of cancerous intestinal mucosal cells were obtained by Laser Capture Microdissection (LCM) and compared by 2-D DIGE. Significant spots were identified by mass spectrometry. After IPA, three proteins [EB1, HSPB1, and Annexin 5 (ANXA5)] were chosen for further validation by Western blotting and tissue microarray-based immunohistochemistry. Conclusions This study identified significant differences in protein expression of colorectal carcinoma cells from UCC patients compared to patients with SCC. Particularly, EB1 was validated in an independent clinical cohort.
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Affiliation(s)
- Timo Gemoll
- Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany
| | - Sophie L Kollbeck
- Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany
| | - Karl F Karstens
- Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany
| | - Gia G Hò
- Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany
| | - Sonja Hartwig
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Düsseldorf, Leibniz Center for Diabetes Research, D-40225 Düsseldorf, Germany.,German Center for Diabetes Research (DZD), D-85764 München-Neuherberg, Germany
| | - Sarah Strohkamp
- Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany
| | - Katharina Schillo
- Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany
| | - Christoph Thorns
- Department of Pathology, University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany
| | - Martina Oberländer
- Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany
| | - Kathrin Kalies
- Institute of Anatomy, University of Lübeck, D-23538 Lübeck, Germany
| | - Stefan Lehr
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Düsseldorf, Leibniz Center for Diabetes Research, D-40225 Düsseldorf, Germany.,German Center for Diabetes Research (DZD), D-85764 München-Neuherberg, Germany
| | - Jens K Habermann
- Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Hospital Schleswig-Holstein, Campus Lübeck, D-23538 Lübeck, Germany
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16
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Regulation of Skeletal Myoblast Differentiation by Drebrin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1006:361-373. [DOI: 10.1007/978-4-431-56550-5_22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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17
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Ansseau E, Eidahl JO, Lancelot C, Tassin A, Matteotti C, Yip C, Liu J, Leroy B, Hubeau C, Gerbaux C, Cloet S, Wauters A, Zorbo S, Meyer P, Pirson I, Laoudj-Chenivesse D, Wattiez R, Harper SQ, Belayew A, Coppée F. Homologous Transcription Factors DUX4 and DUX4c Associate with Cytoplasmic Proteins during Muscle Differentiation. PLoS One 2016; 11:e0146893. [PMID: 26816005 PMCID: PMC4729438 DOI: 10.1371/journal.pone.0146893] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 12/24/2015] [Indexed: 12/26/2022] Open
Abstract
Hundreds of double homeobox (DUX) genes map within 3.3-kb repeated elements dispersed in the human genome and encode DNA-binding proteins. Among these, we identified DUX4, a potent transcription factor that causes facioscapulohumeral muscular dystrophy (FSHD). In the present study, we performed yeast two-hybrid screens and protein co-purifications with HaloTag-DUX fusions or GST-DUX4 pull-down to identify protein partners of DUX4, DUX4c (which is identical to DUX4 except for the end of the carboxyl terminal domain) and DUX1 (which is limited to the double homeodomain). Unexpectedly, we identified and validated (by co-immunoprecipitation, GST pull-down, co-immunofluorescence and in situ Proximal Ligation Assay) the interaction of DUX4, DUX4c and DUX1 with type III intermediate filament protein desmin in the cytoplasm and at the nuclear periphery. Desmin filaments link adjacent sarcomere at the Z-discs, connect them to sarcolemma proteins and interact with mitochondria. These intermediate filament also contact the nuclear lamina and contribute to positioning of the nuclei. Another Z-disc protein, LMCD1 that contains a LIM domain was also validated as a DUX4 partner. The functionality of DUX4 or DUX4c interactions with cytoplasmic proteins is underscored by the cytoplasmic detection of DUX4/DUX4c upon myoblast fusion. In addition, we identified and validated (by co-immunoprecipitation, co-immunofluorescence and in situ Proximal Ligation Assay) as DUX4/4c partners several RNA-binding proteins such as C1QBP, SRSF9, RBM3, FUS/TLS and SFPQ that are involved in mRNA splicing and translation. FUS and SFPQ are nuclear proteins, however their cytoplasmic translocation was reported in neuronal cells where they associated with ribonucleoparticles (RNPs). Several other validated or identified DUX4/DUX4c partners are also contained in mRNP granules, and the co-localizations with cytoplasmic DAPI-positive spots is in keeping with such an association. Large muscle RNPs were recently shown to exit the nucleus via a novel mechanism of nuclear envelope budding. Following DUX4 or DUX4c overexpression in muscle cell cultures, we observed their association with similar nuclear buds. In conclusion, our study demonstrated unexpected interactions of DUX4/4c with cytoplasmic proteins playing major roles during muscle differentiation. Further investigations are on-going to evaluate whether these interactions play roles during muscle regeneration as previously suggested for DUX4c.
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Affiliation(s)
- Eugénie Ansseau
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Jocelyn O. Eidahl
- Center for Gene Therapy, Research Institute at Nationwide Children's Hospital, Columbus, OH, United States of America
| | - Céline Lancelot
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Alexandra Tassin
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Christel Matteotti
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Cassandre Yip
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Jian Liu
- Center for Gene Therapy, Research Institute at Nationwide Children's Hospital, Columbus, OH, United States of America
| | - Baptiste Leroy
- Laboratory of Proteomic and Microbiology, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Céline Hubeau
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Cécile Gerbaux
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Samuel Cloet
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Armelle Wauters
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Sabrina Zorbo
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Pierre Meyer
- Pediatric Department, CHRU Montpellier, Montpellier, France
| | - Isabelle Pirson
- I.R.I.B.H.M., Free University of Brussels, Brussels, Belgium
| | | | - Ruddy Wattiez
- Laboratory of Proteomic and Microbiology, Research Institute for Biosciences, University of Mons, Mons, Belgium
| | - Scott Q. Harper
- Center for Gene Therapy, Research Institute at Nationwide Children's Hospital, Columbus, OH, United States of America
- Department of Pediatrics, Ohio State University College of Medicine, Columbus, OH, United States of America
| | - Alexandra Belayew
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
| | - Frédérique Coppée
- Laboratory of Molecular Biology, Research Institute for Health Sciences and Technology, University of Mons, Mons, Belgium
- * E-mail:
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18
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Zhang T, Taylor J, Jiang Y, Pereyra AS, Messi ML, Wang ZM, Hereñú C, Delbono O. Troponin T3 regulates nuclear localization of the calcium channel Cavβ1a subunit in skeletal muscle. Exp Cell Res 2015; 336:276-86. [PMID: 25981458 DOI: 10.1016/j.yexcr.2015.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/06/2015] [Indexed: 11/24/2022]
Abstract
The voltage-gated calcium channel (Cav) β1a subunit (Cavβ1a) plays an important role in excitation-contraction coupling (ECC), a process in the myoplasm that leads to muscle-force generation. Recently, we discovered that the Cavβ1a subunit travels to the nucleus of skeletal muscle cells where it helps to regulate gene transcription. To determine how it travels to the nucleus, we performed a yeast two-hybrid screening of the mouse fast skeletal muscle cDNA library and identified an interaction with troponin T3 (TnT3), which we subsequently confirmed by co-immunoprecipitation and co-localization assays in mouse skeletal muscle in vivo and in cultured C2C12 muscle cells. Interacting domains were mapped to the leucine zipper domain in TnT3 COOH-terminus (160-244 aa) and Cavβ1a NH2-terminus (1-99 aa), respectively. The double fluorescence assay in C2C12 cells co-expressing TnT3/DsRed and Cavβ1a/YFP shows that TnT3 facilitates Cavβ1a nuclear recruitment, suggesting that the two proteins play a heretofore unknown role during early muscle differentiation in addition to their classical role in ECC regulation.
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Affiliation(s)
- Tan Zhang
- Department of Internal Medicine-Gerontology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Jackson Taylor
- Department of Internal Medicine-Gerontology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Yang Jiang
- Department of Internal Medicine-Gerontology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Andrea S Pereyra
- Department of Histology, National University of La Plata, 1900 La Plata, Argentina
| | - Maria Laura Messi
- Department of Internal Medicine-Gerontology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Zhong-Min Wang
- Department of Internal Medicine-Gerontology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Claudia Hereñú
- Department of Histology, National University of La Plata, 1900 La Plata, Argentina
| | - Osvaldo Delbono
- Department of Internal Medicine-Gerontology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA; Neuroscience Program, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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19
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Mogessie B, Roth D, Rahil Z, Straube A. A novel isoform of MAP4 organises the paraxial microtubule array required for muscle cell differentiation. eLife 2015; 4:e05697. [PMID: 25898002 PMCID: PMC4423121 DOI: 10.7554/elife.05697] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/19/2015] [Indexed: 12/22/2022] Open
Abstract
The microtubule cytoskeleton is critical for muscle cell differentiation and undergoes reorganisation into an array of paraxial microtubules, which serves as template for contractile sarcomere formation. In this study, we identify a previously uncharacterised isoform of microtubule-associated protein MAP4, oMAP4, as a microtubule organising factor that is crucial for myogenesis. We show that oMAP4 is expressed upon muscle cell differentiation and is the only MAP4 isoform essential for normal progression of the myogenic differentiation programme. Depletion of oMAP4 impairs cell elongation and cell–cell fusion. Most notably, oMAP4 is required for paraxial microtubule organisation in muscle cells and prevents dynein- and kinesin-driven microtubule–microtubule sliding. Purified oMAP4 aligns dynamic microtubules into antiparallel bundles that withstand motor forces in vitro. We propose a model in which the cooperation of dynein-mediated microtubule transport and oMAP4-mediated zippering of microtubules drives formation of a paraxial microtubule array that provides critical support for the polarisation and elongation of myotubes. DOI:http://dx.doi.org/10.7554/eLife.05697.001 Skeletal muscles—which enable animals to move—are made up of large elongated muscle cells that span the entire length of the muscle. These cells contain stacks of structures called sarcomeres that enable the cells to contract and generate the force required for movement. Cells called myoblasts elongate and fuse together at their tips to make the muscle cells. Within the myoblasts, long filaments called microtubules are arranged in an overlapping linear pattern. The filaments act as a template that helps the sarcomeres to align as the muscle cells form. A family of microtubule-associated proteins (or ‘MAPs’ for short) bind to microtubules and assist in organising the filaments, but it is not clear how they work. Mogessie et al. used microscopy to observe the formation of the microtubule filaments in living myoblasts. The experiments show that the filaments progressively become more ordered as the myoblasts develop into muscle cells. Mogessie et al. identified a new member of the MAP family that is produced in myoblasts as soon as they start to form muscle fibres, and named it oMAP4. The microtubules in cells that make smaller amounts of this protein were more disorganised, and these cells were unable to fuse with each other to form muscle cells. The experiments also found that oMAP4 can create links between different microtubules and act as a brake to prevent the filaments being moved excessively by motor proteins. Therefore, Mogessie et al. suggest that oMAP4 contributes to the formation of a strong and stable arrangement of filaments. This, in turn, allows the muscle cells to become very long. Making more oMAP4 alone is not sufficient to form the elongated muscle cells. Therefore, the next challenge is to understand how other processes—such as the selective stabilisation of some microtubules and the movement of cell materials along the microtubules—cooperate to control muscle fibre formation. DOI:http://dx.doi.org/10.7554/eLife.05697.002
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Affiliation(s)
- Binyam Mogessie
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Daniel Roth
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Zainab Rahil
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Anne Straube
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, United Kingdom
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Nguyen NUN, Wang HV. Dual roles of palladin protein in in vitro myogenesis: inhibition of early induction but promotion of myotube maturation. PLoS One 2015; 10:e0124762. [PMID: 25875253 PMCID: PMC4396843 DOI: 10.1371/journal.pone.0124762] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 03/06/2015] [Indexed: 12/28/2022] Open
Abstract
Palladin is a microfilament-associated phosphoprotein whose function in skeletal muscle has rarely been studied. Therefore, we investigate whether myogenesis is influenced by the depletion of palladin expression known to interfere with the actin cytoskeleton dynamic required for skeletal muscle differentiation. The inhibition of palladin in C2C12 myoblasts leads to precocious myogenic differentiation with a concomitant reduction in cell apoptosis. This premature myogenesis is caused, in part, by an accelerated induction of p21, myogenin, and myosin heavy chain, suggesting that palladin acts as a negative regulator in early differentiation phases. Paradoxically, palladin-knockdown myoblasts are unable to differentiate terminally, despite their ability to perform some initial steps of differentiation. Cells with attenuated palladin expression form thinner myotubes with fewer myonuclei compared to those of the control. It is noteworthy that a negative regulator of myogenesis, myostatin, is activated in palladin-deficient myotubes, suggesting the palladin-mediated impairment of late-stage myogenesis. Additionally, overexpression of 140-kDa palladin inhibits myoblast differentiation while 200-kDa and 90-kDa palladin-overexpressed cells display an enhanced differentiation rate. Together, our data suggest that palladin might have both positive and negative roles in maintaining the proper skeletal myogenic differentiation in vitro.
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Affiliation(s)
- Ngoc-Uyen-Nhi Nguyen
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
- Center for Cell Dynamics, National Cheng Kung University, Tainan, Taiwan
| | - Hao-Ven Wang
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
- University Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
- Center for Cell Dynamics, National Cheng Kung University, Tainan, Taiwan
- * E-mail:
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21
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Katsetos CD, Reginato MJ, Baas PW, D'Agostino L, Legido A, Tuszyn Ski JA, Dráberová E, Dráber P. Emerging microtubule targets in glioma therapy. Semin Pediatr Neurol 2015; 22:49-72. [PMID: 25976261 DOI: 10.1016/j.spen.2015.03.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Major advances in the genomics and epigenomics of diffuse gliomas and glioblastoma to date have not been translated into effective therapy, necessitating pursuit of alternative treatment approaches for these therapeutically challenging tumors. Current knowledge of microtubules in cancer and the development of new microtubule-based treatment strategies for high-grade gliomas are the topic in this review article. Discussed are cellular, molecular, and pharmacologic aspects of the microtubule cytoskeleton underlying mitosis and interactions with other cellular partners involved in cell cycle progression, directional cell migration, and tumor invasion. Special focus is placed on (1) the aberrant overexpression of βIII-tubulin, a survival factor associated with hypoxic tumor microenvironment and dynamic instability of microtubules; (2) the ectopic overexpression of γ-tubulin, which in addition to its conventional role as a microtubule-nucleating protein has recently emerged as a transcription factor interacting with oncogenes and kinases; (3) the microtubule-severing ATPase spastin and its emerging role in cell motility of glioblastoma cells; and (4) the modulating role of posttranslational modifications of tubulin in the context of interaction of microtubules with motor proteins. Specific antineoplastic strategies discussed include downregulation of targeted molecules aimed at achieving a sensitization effect on currently used mainstay therapies. The potential role of new classes of tubulin-binding agents and ATPase inhibitors is also examined. Understanding the cellular and molecular mechanisms underpinning the distinct behaviors of microtubules in glioma tumorigenesis and drug resistance is key to the discovery of novel molecular targets that will fundamentally change the prognostic outlook of patients with diffuse high-grade gliomas.
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Affiliation(s)
- Christos D Katsetos
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA; Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Philadelphia, PA.
| | - Mauricio J Reginato
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA
| | - Luca D'Agostino
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA
| | - Agustin Legido
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA
| | - Jack A Tuszyn Ski
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta, Canada; Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Eduarda Dráberová
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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22
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Abel AM, Schuldt KM, Rajasekaran K, Hwang D, Riese MJ, Rao S, Thakar MS, Malarkannan S. IQGAP1: insights into the function of a molecular puppeteer. Mol Immunol 2015; 65:336-49. [PMID: 25733387 DOI: 10.1016/j.molimm.2015.02.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/09/2015] [Accepted: 02/09/2015] [Indexed: 02/06/2023]
Abstract
The intracellular spatiotemporal organization of signaling events is critical for normal cellular function. In response to environmental stimuli, cells utilize highly organized signaling pathways that are subject to multiple layers of regulation. However, the molecular mechanisms that coordinate these complex processes remain an enigma. Scaffolding proteins (scaffolins) have emerged as critical regulators of signaling pathways, many of which have well-described functions in immune cells. IQGAP1, a highly conserved cytoplasmic scaffold protein, is able to curb, compartmentalize, and coordinate multiple signaling pathways in a variety of cell types. IQGAP1 plays a central role in cell-cell interaction, cell adherence, and movement via actin/tubulin-based cytoskeletal reorganization. Evidence also implicates IQGAP1 as an essential regulator of the MAPK and Wnt/β-catenin signaling pathways. Here, we summarize the recent advances on the cellular and molecular biology of IQGAP1. We also describe how this pleiotropic scaffolin acts as a true molecular puppeteer, and highlight the significance of future research regarding the role of IQGAP1 in immune cells.
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Affiliation(s)
- Alex M Abel
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Microbiology & Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Kristina M Schuldt
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Kamalakannan Rajasekaran
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - David Hwang
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Matthew J Riese
- Department of Microbiology & Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Sridhar Rao
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Monica S Thakar
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Subramaniam Malarkannan
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Microbiology & Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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23
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Galva C, Kirik V, Lindeboom JJ, Kaloriti D, Rancour DM, Hussey PJ, Bednarek SY, Ehrhardt DW, Sedbrook JC. The microtubule plus-end tracking proteins SPR1 and EB1b interact to maintain polar cell elongation and directional organ growth in Arabidopsis. THE PLANT CELL 2014; 26:4409-25. [PMID: 25415978 PMCID: PMC4277225 DOI: 10.1105/tpc.114.131482] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The microtubule plus-end tracking proteins (+TIPs) END BINDING1b (EB1b) and SPIRAL1 (SPR1) are required for normal cell expansion and organ growth. EB proteins are viewed as central regulators of +TIPs and cell polarity in animals; SPR1 homologs are specific to plants. To explore if EB1b and SPR1 fundamentally function together, we combined genetic, biochemical, and cell imaging approaches in Arabidopsis thaliana. We found that eb1b-2 spr1-6 double mutant roots exhibit substantially more severe polar expansion defects than either single mutant, undergoing right-looping growth and severe axial twisting instead of waving on tilted hard-agar surfaces. Protein interaction assays revealed that EB1b and SPR1 bind each other and tubulin heterodimers, which is suggestive of a microtubule loading mechanism. EB1b and SPR1 show antagonistic association with microtubules in vitro. Surprisingly, our combined analyses revealed that SPR1 can load onto microtubules and function independently of EB1 proteins, setting SPR1 apart from most studied +TIPs in animals and fungi. Moreover, we found that the severity of defects in microtubule dynamics in spr1 eb1b mutant hypocotyl cells correlated well with the severity of growth defects. These data indicate that SPR1 and EB1b have complex interactions as they load onto microtubule plus ends and direct polar cell expansion and organ growth in response to directional cues.
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Affiliation(s)
- Charitha Galva
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790
| | - Viktor Kirik
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790
| | | | - Despoina Kaloriti
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790
| | - David M Rancour
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Patrick J Hussey
- School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | | | | | - John C Sedbrook
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790
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24
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Poliakova K, Adebola A, Leung CL, Favre B, Liem RKH, Schepens I, Borradori L. BPAG1a and b associate with EB1 and EB3 and modulate vesicular transport, Golgi apparatus structure, and cell migration in C2.7 myoblasts. PLoS One 2014; 9:e107535. [PMID: 25244344 PMCID: PMC4171495 DOI: 10.1371/journal.pone.0107535] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 08/18/2014] [Indexed: 11/19/2022] Open
Abstract
BPAG1a and BPAG1b (BPAG1a/b) constitute two major isoforms encoded by the dystonin (Dst) gene and show homology with MACF1a and MACF1b. These proteins are members of the plakin family, giant multi-modular proteins able to connect the intermediate filament, microtubule and microfilament cytoskeletal networks with each other and to distinct cell membrane sites. They also serve as scaffolds for signaling proteins that modulate cytoskeletal dynamics. To gain better insights into the functions of BPAG1a/b, we further characterized their C-terminal region important for their interaction with microtubules and assessed the role of these isoforms in the cytoskeletal organization of C2.7 myoblast cells. Our results show that alternative splicing does not only occur at the 5′ end of Dst and Macf1 pre-mRNAs, as previously reported, but also at their 3′ end, resulting in expression of additional four mRNA variants of BPAG1 and MACF1. These isoform-specific C-tails were able to bundle microtubules and bound to both EB1 and EB3, two microtubule plus end proteins. In the C2.7 cell line, knockdown of BPAG1a/b had no major effect on the organization of the microtubule and microfilament networks, but negatively affected endocytosis and maintenance of the Golgi apparatus structure, which became dispersed. Finally, knockdown of BPAG1a/b caused a specific decrease in the directness of cell migration, but did not impair initial cell adhesion. These data provide novel insights into the complexity of alternative splicing of Dst pre-mRNAs and into the role of BPAG1a/b in vesicular transport, Golgi apparatus structure as well as in migration in C2.7 myoblasts.
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Affiliation(s)
- Kseniia Poliakova
- Department of Clinical Research, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
- Department of Dermatology, Inselspital, Bern University Hospital, Bern, Switzerland
- * E-mail:
| | - Adijat Adebola
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
| | - Conrad L. Leung
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
| | - Bertrand Favre
- Department of Clinical Research, University of Bern, Bern, Switzerland
- Department of Dermatology, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Ronald K. H. Liem
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
| | - Isabelle Schepens
- Department of Clinical Research, University of Bern, Bern, Switzerland
| | - Luca Borradori
- Department of Clinical Research, University of Bern, Bern, Switzerland
- Department of Dermatology, Inselspital, Bern University Hospital, Bern, Switzerland
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25
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Alieva IB. Role of microtubule cytoskeleton in regulation of endothelial barrier function. BIOCHEMISTRY (MOSCOW) 2014; 79:964-75. [DOI: 10.1134/s0006297914090119] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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26
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Nguyen NUN, Liang VR, Wang HV. Actin-associated protein palladin is required for migration behavior and differentiation potential of C2C12 myoblast cells. Biochem Biophys Res Commun 2014; 452:728-33. [DOI: 10.1016/j.bbrc.2014.08.143] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 08/26/2014] [Indexed: 11/17/2022]
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27
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Fife CM, McCarroll JA, Kavallaris M. Movers and shakers: cell cytoskeleton in cancer metastasis. Br J Pharmacol 2014; 171:5507-23. [PMID: 24665826 DOI: 10.1111/bph.12704] [Citation(s) in RCA: 360] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 03/14/2014] [Accepted: 03/18/2014] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Metastasis is responsible for the greatest number of cancer deaths. Metastatic disease, or the movement of cancer cells from one site to another, is a complex process requiring dramatic remodelling of the cell cytoskeleton. The various components of the cytoskeleton, actin (microfilaments), microtubules (MTs) and intermediate filaments, are highly integrated and their functions are well orchestrated in normal cells. In contrast, mutations and abnormal expression of cytoskeletal and cytoskeletal-associated proteins play an important role in the ability of cancer cells to resist chemotherapy and metastasize. Studies on the role of actin and its interacting partners have highlighted key signalling pathways, such as the Rho GTPases, and downstream effector proteins that, through the cytoskeleton, mediate tumour cell migration, invasion and metastasis. An emerging role for MTs in tumour cell metastasis is being unravelled and there is increasing interest in the crosstalk between key MT interacting proteins and the actin cytoskeleton, which may provide novel treatment avenues for metastatic disease. Improved understanding of how the cytoskeleton and its interacting partners influence tumour cell migration and metastasis has led to the development of novel therapeutics against aggressive and metastatic disease. LINKED ARTICLES This article is part of a themed section on Cytoskeleton, Extracellular Matrix, Cell Migration, Wound Healing and Related Topics. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-24.
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Affiliation(s)
- C M Fife
- Tumour Biology and Targeting Program, Children's Cancer Institute Australia Lowy Cancer Research Centre, UNSW Australia, Randwick, NSW, Australia; Australian Centre for NanoMedicine, UNSW Australia, Sydney, NSW, Australia
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28
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Plestant C, Strale PO, Seddiki R, Nguyen E, Ladoux B, Mège RM. Adhesive interactions of N-cadherin limit the recruitment of microtubules to cell–cell contacts through organization of actomyosin. J Cell Sci 2014; 127:1660-71. [DOI: 10.1242/jcs.131284] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
ABSTRACT
Adhesive interactions of cadherins induce crosstalk between adhesion complexes and the actin cytoskeleton, allowing strengthening of adhesions and cytoskeletal organization. The underlying mechanisms are not completely understood, and microtubules (MTs) might be involved, as for integrin-mediated cell–extracellular-matrix adhesions. Therefore, we investigated the relationship between N-cadherin and MTs by analyzing the influence of N-cadherin engagement on MT distribution and dynamics. MTs progressed less, with a lower elongation rate, towards cadherin adhesions than towards focal adhesions. Increased actin treadmilling and the presence of an actomyosin contractile belt, suggested that actin relays inhibitory signals from cadherin adhesions to MTs. The reduced rate of MT elongation, associated with reduced recruitment of end-binding (EB) proteins to plus ends, was alleviated by expression of truncated N-cadherin, but was only moderately affected when actomyosin was disrupted. By contrast, destabilizing actomyosin fibers allowed MTs to enter the adhesion area, suggesting that tangential actin bundles impede MT growth independently of MT dynamics. Blocking MT penetration into the adhesion area strengthened cadherin adhesions. Taken together, these results establish a crosstalk between N-cadherin, F-actin and MTs. The opposing effects of cadherin and integrin engagement on actin organization and MT distribution might induce bias of the MT network during cell polarization.
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Affiliation(s)
- Charlotte Plestant
- Institut du Fer à Moulin, UMRS 839 INSERM, Université Pierre et Marie Curie, 75005 Paris, France
| | - Pierre-Olivier Strale
- Institut du Fer à Moulin, UMRS 839 INSERM, Université Pierre et Marie Curie, 75005 Paris, France
| | - Rima Seddiki
- Institut du Fer à Moulin, UMRS 839 INSERM, Université Pierre et Marie Curie, 75005 Paris, France
- Institut Jacques Monod, UMR7592 CNRS, Université Paris Diderot, 75013 Paris, France
| | - Emmanuelle Nguyen
- Mechanobiology Institute, National University of Singapore, 117411 Singapore
| | - Benoit Ladoux
- Institut Jacques Monod, UMR7592 CNRS, Université Paris Diderot, 75013 Paris, France
- Mechanobiology Institute, National University of Singapore, 117411 Singapore
| | - René-Marc Mège
- Institut du Fer à Moulin, UMRS 839 INSERM, Université Pierre et Marie Curie, 75005 Paris, France
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Abstract
The function of muscle is to contract, which means to exert force on a substrate. The adaptations required for skeletal muscle differentiation, from a prototypic cell, involve specialization of housekeeping cytoskeletal contracting and supporting systems into crystalline arrays of proteins. Here I discuss the changes that all three cytoskeletal systems (microfilaments, intermediate filaments, and microtubules) undergo through myogenesis. I also discuss their interaction, through the membrane, to extracellular matrix and to other cells, where force will be exerted during contraction. The three cytoskeletal systems are necessary for the muscle cell and must exert complementary roles in the cell. Muscle is a responsive system, where structure and function are integrated: the structural adaptations it undergoes depend on force production. In this way, the muscle cytoskeleton is a portrait of its physiology. I review the cytoskeletal proteins and structures involved in muscle function and focus particularly on their role in myogenesis, the process by which this incredible muscle machine is made. Although the focus is on skeletal muscle, some of the discussion is applicable to cardiac and smooth muscle.
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30
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Abstract
Dystrophin and utrophin are highly similar proteins that both link cortical actin filaments with a complex of sarcolemmal glycoproteins, yet localize to different subcellular domains within normal muscle cells. In mdx mice and Duchenne muscular dystrophy patients, dystrophin is lacking and utrophin is consequently up-regulated and redistributed to locations normally occupied by dystrophin. Transgenic overexpression of utrophin has been shown to significantly improve aspects of the disease phenotype in the mdx mouse; therefore, utrophin up-regulation is under intense investigation as a potential therapy for Duchenne muscular dystrophy. Here we biochemically compared the previously documented microtubule binding activity of dystrophin with utrophin and analyzed several transgenic mouse models to identify phenotypes of the mdx mouse that remain despite transgenic utrophin overexpression. Our in vitro analyses revealed that dystrophin binds microtubules with high affinity and pauses microtubule polymerization, whereas utrophin has no activity in either assay. We also found that transgenic utrophin overexpression does not correct subsarcolemmal microtubule lattice disorganization, loss of torque production after in vivo eccentric contractions, or physical inactivity after mild exercise. Finally, our data suggest that exercise-induced inactivity correlates with loss of sarcolemmal neuronal NOS localization in mdx muscle, whereas loss of in vivo torque production after eccentric contraction-induced injury is associated with microtubule lattice disorganization.
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31
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Alieva IB, Zemskov EA, Smurova KM, Kaverina IN, Verin AD. The leading role of microtubules in endothelial barrier dysfunction: disassembly of peripheral microtubules leaves behind the cytoskeletal reorganization. J Cell Biochem 2014; 114:2258-72. [PMID: 23606375 DOI: 10.1002/jcb.24575] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 04/11/2013] [Indexed: 01/23/2023]
Abstract
Disturbance of the endothelial barrier is characterized by dramatic cytoskeleton reorganization, activation of actomyosin contraction and, finally, leads to intercellular gap formation. Here we demonstrate that the edemagenic agent, thrombin, causes a rapid increase in the human pulmonary artery endothelial cell (EC) barrier permeability accompanied by fast decreasing in the peripheral microtubules quantity and reorganization of the microtubule system in the internal cytoplasm of the EC within 5 min of the treatment. The actin stress-fibers formation occurs gradually and the maximal effect is observed relatively later, 30 min of the thrombin treatment. Thus, microtubules reaction develops faster than the reorganization of the actin filaments system responsible for the subsequent changes of the cell shape during barrier dysfunction development. Direct microtubules depolymerization by nocodazole initiates the cascade of barrier dysfunction reactions. Nocodazole-induced barrier disruption is connected directly with the degree of peripheral microtubules depolymerization. Short-term loss of endothelial barrier function occurs at the minimal destruction of peripheral microtubules, when actin filament system is still intact. Specifically, we demonstrate that the EC microtubule dynamics examined by time-lapse imaging of EB3-GFP comets movement has changed under these conditions: microtubule plus ends growth rate significantly decreased near the cell periphery. The microtubules, apparently, are the first target in the circuit of reactions leading to the pulmonary EC barrier compromise. Our results show that dynamic microtubules play an essential role in the barrier function in vitro; peripheral microtubules depolymerization is necessary and sufficient condition for initiation of endothelial barrier dysfunction.
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Affiliation(s)
- Irina B Alieva
- Electron Microscopy Department, AN Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.
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32
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Stypula-Cyrus Y, Mutyal NN, Dela Cruz M, Kunte DP, Radosevich AJ, Wali R, Roy HK, Backman V. End-binding protein 1 (EB1) up-regulation is an early event in colorectal carcinogenesis. FEBS Lett 2014; 588:829-35. [PMID: 24492008 DOI: 10.1016/j.febslet.2014.01.046] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/20/2014] [Indexed: 11/19/2022]
Abstract
End-binding protein (EB1) is a microtubule protein that binds to the tumor suppressor adenomatous polyposis coli (APC). While EB1 is implicated as a potential oncogene, its role in cancer progression is unknown. Therefore, we analyzed EB1/APC expression at the earliest stages of colorectal carcinogenesis and in the uninvolved mucosa ("field effect") of human and animal tissue. We also performed siRNA-knockdown in colon cancer cell lines. EB1 is up-regulated in early and field carcinogenesis in the colon, and the cellular/nano-architectural effect of EB1 knockdown depended on the genetic context. Thus, dysregulation of EB1 is an important early event in colon carcinogenesis.
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Affiliation(s)
- Yolanda Stypula-Cyrus
- Biomedical Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - Nikhil N Mutyal
- Biomedical Engineering Department, Northwestern University, Evanston, IL 60208, USA
| | - Mart Dela Cruz
- Department of Medicine, Boston Medical Center, Boston, MA 02118, USA
| | - Dhananjay P Kunte
- Department of Internal Medicine, NorthShore University Health System, Evanston, IL 60201, USA
| | - Andrew J Radosevich
- Biomedical Engineering Department, Northwestern University, Evanston, IL 60208, USA
| | - Ramesh Wali
- Department of Medicine, Boston Medical Center, Boston, MA 02118, USA
| | - Hemant K Roy
- Department of Medicine, Boston Medical Center, Boston, MA 02118, USA.
| | - Vadim Backman
- Biomedical Engineering Department, Northwestern University, Evanston, IL 60208, USA
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33
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Leśniewska K, Warbrick E, Ohkura H. Peptide aptamers define distinct EB1- and EB3-binding motifs and interfere with microtubule dynamics. Mol Biol Cell 2014; 25:1025-36. [PMID: 24478452 PMCID: PMC3967968 DOI: 10.1091/mbc.e13-08-0504] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This study isolated many peptide aptamers containing the SxIP motif that binds to Drosophila EB1 and human EB1 and EB3. Interaction sequences are similar to but distinct from each other. Aptamers can competitively displace endogenous EB1-interacting proteins from microtubule plus ends, and their expression in developing flies alters microtubule dynamics. EB1 is a conserved protein that plays a central role in regulating microtubule dynamics and organization. It binds directly to microtubule plus ends and recruits other plus end–localizing proteins. Most EB1-binding proteins contain a Ser–any residue–Ile-Pro (SxIP) motif. Here we describe the isolation of peptide aptamers with optimized versions of this motif by screening for interaction with the Drosophila EB1 protein. The use of small peptide aptamers to competitively inhibit protein interaction and function is becoming increasingly recognized as a powerful technique. We show that SxIP aptamers can bind microtubule plus ends in cells and functionally act to displace interacting proteins by competitive binding. Their expression in developing flies can interfere with microtubules, altering their dynamics. We also identify aptamers binding to human EB1 and EB3, which have sequence requirements similar to but distinct from each other and from Drosophila EB1. This suggests that EB1 paralogues within one species may interact with overlapping but distinct sets of proteins in cells.
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Affiliation(s)
- Karolina Leśniewska
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom Division of Molecular Medicine, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
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34
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Folker ES, Schulman VK, Baylies MK. Translocating myonuclei have distinct leading and lagging edges that require kinesin and dynein. Development 2013; 141:355-66. [PMID: 24335254 DOI: 10.1242/dev.095612] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Nuclei are precisely positioned within all cells, and mispositioned nuclei are a hallmark of many muscle diseases. Myonuclear positioning is dependent on Kinesin and Dynein, but interactions between these motor proteins and their mechanisms of action are unclear. We find that in developing Drosophila muscles, Dynein and Kinesin work together to move nuclei in a single direction by two separate mechanisms that are spatially segregated. First, the two motors work together in a sequential pathway that acts from the cell cortex at the muscle poles. This mechanism requires Kinesin-dependent localization of Dynein to cell cortex near the muscle pole. From this location Dynein can pull microtubule minus-ends and the attached myonuclei toward the muscle pole. Second, the motors exert forces directly on individual nuclei independently of the cortical pathway. However, the activities of the two motors on the nucleus are polarized relative to the direction of myonuclear translocation: Kinesin acts at the leading edge of the nucleus, whereas Dynein acts at the lagging edge of the nucleus. Consistent with the activities of Kinesin and Dynein being polarized on the nucleus, nuclei rarely change direction, and those that do, reorient to maintain the same leading edge. Conversely, nuclei in both Kinesin and Dynein mutant embryos change direction more often and do not maintain the same leading edge when changing directions. These data implicate Kinesin and Dynein in two distinct and independently regulated mechanisms of moving myonuclei, which together maximize the ability of myonuclei to achieve their proper localizations within the constraints imposed by embryonic development.
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Affiliation(s)
- Eric S Folker
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY 10065, USA
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Pustylnik S, Fiorino C, Nabavi N, Zappitelli T, da Silva R, Aubin JE, Harrison RE. EB1 levels are elevated in ascorbic Acid (AA)-stimulated osteoblasts and mediate cell-cell adhesion-induced osteoblast differentiation. J Biol Chem 2013; 288:22096-110. [PMID: 23740245 DOI: 10.1074/jbc.m113.481515] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Osteoblasts are differentiated mesenchymal cells that function as the major bone-producing cells of the body. Differentiation cues including ascorbic acid (AA) stimulation provoke intracellular changes in osteoblasts leading to the synthesis of the organic portion of the bone, which includes collagen type I α1, proteoglycans, and matrix proteins, such as osteocalcin. During our microarray analysis of AA-stimulated osteoblasts, we observed a significant up-regulation of the microtubule (MT) plus-end binding protein, EB1, compared with undifferentiated osteoblasts. EB1 knockdown significantly impaired AA-induced osteoblast differentiation, as detected by reduced expression of osteoblast differentiation marker genes. Intracellular examination of AA-stimulated osteoblasts treated with EB1 siRNA revealed a reduction in MT stability with a concomitant loss of β-catenin distribution at the cell cortex and within the nucleus. Diminished β-catenin levels in EB1 siRNA-treated osteoblasts paralleled an increase in phospho-β-catenin and active glycogen synthase kinase 3β, a kinase known to target β-catenin to the proteasome. EB1 siRNA treatment also reduced the expression of the β-catenin gene targets, cyclin D1 and Runx2. Live immunofluorescent imaging of differentiated osteoblasts revealed a cortical association of EB1-mcherry with β-catenin-GFP. Immunoprecipitation analysis confirmed an interaction between EB1 and β-catenin. We also determined that cell-cell contacts and cortically associated EB1/β-catenin interactions are necessary for osteoblast differentiation. Finally, using functional blocking antibodies, we identified E-cadherin as a major contributor to the cell-cell contact-induced osteoblast differentiation.
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Affiliation(s)
- Sofia Pustylnik
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
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Zhang T, Birbrair A, Wang ZM, Taylor J, Messi ML, Delbono O. Troponin T nuclear localization and its role in aging skeletal muscle. AGE (DORDRECHT, NETHERLANDS) 2013; 35:353-370. [PMID: 22189912 PMCID: PMC3592954 DOI: 10.1007/s11357-011-9368-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 12/08/2011] [Indexed: 05/31/2023]
Abstract
Troponin T (TnT) is known to mediate the interaction between Tn complex and tropomyosin (Tm), which is essential for calcium-activated striated muscle contraction. This regulatory function takes place in the myoplasm, where TnT binds Tm. However, recent findings of troponin I and Tm nuclear translocation in Drosophila and mammalian cells imply other roles for the Tn-Tm complex. We hypothesized that TnT plays a nonclassical role through nuclear translocation. Immunoblotting with different antibodies targeting the NH2- or COOH-terminal region uncovered a pool of fast skeletal muscle TnT3 localized in the nuclear fraction of mouse skeletal muscle as either an intact or fragmented protein. Construction of TnT3-DsRed fusion proteins led to the further observation that TnT3 fragments are closely related to nucleolus and RNA polymerase activity, suggesting a role for TnT3 in regulating transcription. Functionally, overexpression of TnT3 fragments produced significant defects in nuclear shape and caused high levels of apoptosis. Interestingly, nuclear TnT3 and its fragments were highly regulated by aging, thus creating a possible link between the deleterious effects of TnT3 and sarcopenia. We propose that changes in nuclear TnT3 and its fragments cause the number of myonuclei to decrease with age, contributing to muscle damage and wasting.
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Affiliation(s)
- Tan Zhang
- />Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157 USA
| | - Alexander Birbrair
- />Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157 USA
- />Neuroscience Program, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157 USA
| | - Zhong-Min Wang
- />Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157 USA
| | - Jackson Taylor
- />Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157 USA
- />Neuroscience Program, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157 USA
| | - María Laura Messi
- />Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157 USA
| | - Osvaldo Delbono
- />Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157 USA
- />Neuroscience Program, Wake Forest School of Medicine, 1 Medical Center Blvd., Winston-Salem, NC 27157 USA
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EB1, p150Glued, and Clasp1 control endothelial tubulogenesis through microtubule assembly, acetylation, and apical polarization. Blood 2013; 121:3521-30. [PMID: 23444400 DOI: 10.1182/blood-2012-11-470179] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Vascular tube morphogenesis requires the establishment of endothelial cell (EC) apical-basal polarity in three-dimensional (3D) extracellular matrices. To date, there is little understanding of how EC polarity is controlled during these highly dynamic and rapid morphogenic events. We show that the microtubule tip complex proteins, end binding 1 (EB1), p150(Glued), and Clasp1, control human EC tube formation by (1) inducing microtubule assembly and asymmetric cytoskeletal polarization, whereby acetylated and detyrosinated tubulins distribute in a subapical membrane location and filamentous actin distributes basally; (2) increasing tubulin posttranslational modifications, including required acetylation events; and (3) regulating an EC lumen signaling cascade that involves membrane type 1 matrix metallopatrinase (MT1-MMP)-dependent proteolysis as well as Pak, Raf, and Erk kinases. Another regulator of this process is the microtubule stabilizing protein, tau, which binds p150(Glued) and similarly affects EC lumen formation by controlling the levels of acetylated and detyrosinated tubulins. Increased expression of the tubulin deacetylases, sirtuin 2, and histone deacetylase 6 (HDAC6), blocks EC tube formation and cytoskeletal polarization, while siRNA suppression of these deacetylases stimulates these events. Overall, this work reveals a fundamental role for microtubule tip complex proteins in coordinating microtubule assembly, posttranslational modifications including acetylation, and apical-basal cytoskeletal polarization to control the developing apical membrane surface during blood vessel tubulogenesis in 3D matrix environments.
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Zhang T, Birbrair A, Delbono O. Nonmyofilament-associated troponin T3 nuclear and nucleolar localization sequence and leucine zipper domain mediate muscle cell apoptosis. Cytoskeleton (Hoboken) 2013; 70:134-47. [PMID: 23378072 DOI: 10.1002/cm.21095] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 12/17/2012] [Accepted: 12/21/2012] [Indexed: 11/07/2022]
Abstract
Troponin T (TnT) plays a major role in striated muscle contraction. We recently demonstrated that the fast skeletal muscle TnT3 isoform is localized in the muscle nucleus, and either its full-length or COOH-terminus leads to muscle cell apoptosis. Here, we further explored the mechanism by which it enters the nucleus and promotes cytotoxicity. Amino acid truncation and substitution showed that its COOH-terminus contains a dominant nuclear/nucleolar localization sequence (KLKRQK) and the basic lysine and arginine residues might play an important role in the nuclear retention and nucleolar enrichment of KLKRQK-DsRed fusion proteins. Deleting this domain or substituting lysine and arginine residues (KLAAQK) resulted in a dramatic loss of TnT3 nuclear and nucleolar localization. In contrast, the GATAKGKVGGRWK domain-DsRed construct localized exclusively in the cytoplasm, indicating that a nuclear exporting sequence is possibly localized in this region. Additionally, we identified a classical DNA-binding leucine zipper domain (LZD) which is conserved among TnT isoforms and species. Deletion of LZD or KLKRQK sequence significantly reduced cell apoptosis compared to full-length TnT3. We conclude that TnT3 contains both a nuclear localization signal and a DNA-binding domain, which may mediate nuclear/nucleolar signaling and muscle cell apoptosis.
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Affiliation(s)
- Tan Zhang
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, 1 Medical Center Boulevard, Winston-Salem, NC 27157, USA
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Goldspink DA, Gadsby JR, Bellett G, Keynton J, Tyrrell BJ, Lund EK, Powell PP, Thomas P, Mogensen MM. The microtubule end-binding protein EB2 is a central regulator of microtubule reorganisation in apico-basal epithelial differentiation. J Cell Sci 2013; 126:4000-14. [DOI: 10.1242/jcs.129759] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Microtubule end-binding (EB) proteins influence microtubule dynamic instability, a process essential for microtubule reorganisation during apico-basal epithelial differentiation. Here we establish for the first time that EB2, but not EB1, expression is critical for initial microtubule reorganisation during apico-basal epithelial differentiation, and that EB2 downregulation promotes bundle formation. EB2 siRNA knockdown during early stages of apico-basal differentiation prevented microtubule reorganisation, while its downregulation at later stages promoted microtubule stability and bundle formation. Interestingly, while EB1 is not essential for microtubule reorganisation its knockdown prevented apico-basal bundle formation and epithelial elongation. EB2 siRNA depletion in undifferentiated epithelial cells induced formation of straight, less dynamic microtubules with EB1 and ACF7 lattice association and co-alignment with actin filaments, a phenotype that could be rescued by formin inhibition. Importantly, in situ inner ear and intestinal crypt epithelial tissue revealed direct correlations between low level of EB2 expression and presence of apico-basal microtubule bundles, which were absent where EB2 was elevated. EB2 is evidently important for initial microtubule reorganisation during epithelial polarisation, while its downregulation facilitates EB1/ACF7 microtubule lattice association, microtubule-actin filament co-alignment and bundle formation. The spatiotemporal expression of EB2 thus dramatically influences microtubule organisation, EB1/ACF7 deployment and epithelial differentiation.
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Malarkannan S, Awasthi A, Rajasekaran K, Kumar P, Schuldt KM, Bartoszek A, Manoharan N, Goldner NK, Umhoefer CM, Thakar MS. IQGAP1: a regulator of intracellular spacetime relativity. THE JOURNAL OF IMMUNOLOGY 2012; 188:2057-63. [PMID: 22345702 DOI: 10.4049/jimmunol.1102439] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Activating and inhibiting receptors of lymphocytes collect valuable information about their mikròs kósmos. This information is essential to initiate or to turn off complex signaling pathways. Irrespective of these advances, our knowledge on how these intracellular activation cascades are coordinated in a spatiotemporal manner is far from complete. Among multiple explanations, the scaffolding proteins have emerged as a critical piece of this evolutionary tangram. Among many, IQGAP1 is one of the essential scaffolding proteins that coordinate multiple signaling pathways. IQGAP1 possesses multiple protein interaction motifs to achieve its scaffolding functions. Using these domains, IQGAP1 has been shown to regulate a number of essential cellular events. This includes actin polymerization, tubulin multimerization, microtubule organizing center formation, calcium/calmodulin signaling, Pak/Raf/Mek1/2-mediated Erk1/2 activation, formation of maestrosome, E-cadherin, and CD44-mediated signaling and glycogen synthase kinase-3/adenomatous polyposis coli-mediated β-catenin activation. In this review, we summarize the recent developments and exciting new findings of cellular functions of IQGAP1.
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Affiliation(s)
- Subramaniam Malarkannan
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Milwaukee, WI 53226, USA.
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Wilson MH, Holzbaur ELF. Opposing microtubule motors drive robust nuclear dynamics in developing muscle cells. J Cell Sci 2012; 125:4158-69. [PMID: 22623723 DOI: 10.1242/jcs.108688] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dynamic interactions with the cytoskeleton drive the movement and positioning of nuclei in many cell types. During muscle cell development, myoblasts fuse to form syncytial myofibers with nuclei positioned regularly along the length of the cell. Nuclear translocation in developing myotubes requires microtubules, but the mechanisms involved have not been elucidated. We find that as nuclei actively translocate through the cell, they rotate in three dimensions. The nuclear envelope, nucleoli and chromocenters within the nucleus rotate together as a unit. Both translocation and rotation require an intact microtubule cytoskeleton, which forms a dynamic bipolar network around nuclei. The plus- and minus-end-directed microtubule motor proteins, kinesin-1 and dynein, localize to the nuclear envelope in myotubes. Kinesin-1 localization is mediated at least in part by interaction with klarsicht/ANC-1/Syne homology (KASH) proteins. Depletion of kinesin-1 abolishes nuclear rotation and significantly inhibits nuclear translocation, resulting in the abnormal aggregation of nuclei at the midline of the myotube. Dynein depletion also inhibits nuclear dynamics, but to a lesser extent, leading to altered spacing between adjacent nuclei. Thus, oppositely directed motors acting from the surface of the nucleus drive nuclear motility in myotubes. The variable dynamics observed for individual nuclei within a single myotube are likely to result from the stochastic activity of competing motors interacting with a complex bipolar microtubule cytoskeleton that is also continuously remodeled as the nuclei move. The three-dimensional rotation of myotube nuclei may facilitate their motility through the complex and crowded cellular environment of the developing muscle cell, allowing for proper myonuclear positioning.
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Affiliation(s)
- Meredith H Wilson
- Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, D400 Richards Building, Philadelphia, PA 19104-6085, USA
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Rudolf A, Buttgereit D, Rexer KH, Renkawitz-Pohl R. The syncytial visceral and somatic musculature develops independently of β3-Tubulin during Drosophila embryogenesis, while maternally supplied β1-Tubulin is stable until the early steps of myoblast fusion. Eur J Cell Biol 2012; 91:192-203. [DOI: 10.1016/j.ejcb.2011.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/15/2011] [Accepted: 11/16/2011] [Indexed: 12/11/2022] Open
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Mian I, Pierre-Louis WS, Dole N, Gilberti RM, Dodge-Kafka K, Tirnauer JS. LKB1 destabilizes microtubules in myoblasts and contributes to myoblast differentiation. PLoS One 2012; 7:e31583. [PMID: 22348111 PMCID: PMC3279410 DOI: 10.1371/journal.pone.0031583] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 01/09/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Skeletal muscle myoblast differentiation and fusion into multinucleate myotubes is associated with dramatic cytoskeletal changes. We find that microtubules in differentiated myotubes are highly stabilized, but premature microtubule stabilization blocks differentiation. Factors responsible for microtubule destabilization in myoblasts have not been identified. FINDINGS We find that a transient decrease in microtubule stabilization early during myoblast differentiation precedes the ultimate microtubule stabilization seen in differentiated myotubes. We report a role for the serine-threonine kinase LKB1 in both microtubule destabilization and myoblast differentiation. LKB1 overexpression reduced microtubule elongation in a Nocodazole washout assay, and LKB1 RNAi increased it, showing LKB1 destabilizes microtubule assembly in myoblasts. LKB1 levels and activity increased during myoblast differentiation, along with activation of the known LKB1 substrates AMP-activated protein kinase (AMPK) and microtubule affinity regulating kinases (MARKs). LKB1 overexpression accelerated differentiation, whereas RNAi impaired it. CONCLUSIONS Reduced microtubule stability precedes myoblast differentiation and the associated ultimate microtubule stabilization seen in myotubes. LKB1 plays a positive role in microtubule destabilization in myoblasts and in myoblast differentiation. This work suggests a model by which LKB1-induced microtubule destabilization facilitates the cytoskeletal changes required for differentiation. Transient destabilization of microtubules might be a useful strategy for enhancing and/or synchronizing myoblast differentiation.
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Affiliation(s)
- Isma Mian
- Center for Molecular Medicine and University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Willythssa Stéphie Pierre-Louis
- Center for Molecular Medicine and University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Neha Dole
- Center for Molecular Medicine and University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Renée M. Gilberti
- Center for Molecular Medicine and University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Kimberly Dodge-Kafka
- Calhoun Center for Cardiology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Jennifer S. Tirnauer
- Center for Molecular Medicine and University of Connecticut Health Center, Farmington, Connecticut, United States of America
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Solute carrier family 3 member 2 (Slc3a2) controls yolk syncytial layer (YSL) formation by regulating microtubule networks in the zebrafish embryo. Proc Natl Acad Sci U S A 2012; 109:3371-6. [PMID: 22331904 DOI: 10.1073/pnas.1200642109] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The yolk syncytial layer (YSL) in the zebrafish embryo is a multinucleated syncytium essential for embryo development, but the molecular mechanisms underlying YSL formation remain largely unknown. Here we show that zebrafish solute carrier family 3 member 2 (Slc3a2) is expressed specifically in the YSL and that slc3a2 knockdown causes severe YSL defects including clustering of the yolk syncytial nuclei and enhanced cell fusion, accompanied by disruption of microtubule networks. Expression of a constitutively active RhoA mimics the YSL phenotypes caused by slc3a2 knockdown, whereas attenuation of RhoA or ROCK activity rescues the slc3a2-knockdown phenotypes. Furthermore, slc3a2 knockdown significantly reduces tyrosine phosphorylation of c-Src, and overexpression of a constitutively active Src restores the slc3a2-knockdown phenotypes. Our data demonstrate a signaling pathway regulating YSL formation in which Slc3a2 inhibits the RhoA/ROCK pathway via phosphorylation of c-Src to modulate YSL microtubule dynamics. This work illuminates processes at a very early stage of zebrafish embryogenesis and more generally informs the mechanism of cell dynamics during syncytium formation.
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Zaal KJM, Reid E, Mousavi K, Zhang T, Mehta A, Bugnard E, Sartorelli V, Ralston E. Who needs microtubules? Myogenic reorganization of MTOC, Golgi complex and ER exit sites persists despite lack of normal microtubule tracks. PLoS One 2011; 6:e29057. [PMID: 22216166 PMCID: PMC3246457 DOI: 10.1371/journal.pone.0029057] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 11/20/2011] [Indexed: 11/18/2022] Open
Abstract
A wave of structural reorganization involving centrosomes, microtubules, Golgi complex and ER exit sites takes place early during skeletal muscle differentiation and completely remodels the secretory pathway. The mechanism of these changes and their functional implications are still poorly understood, in large part because all changes occur seemingly simultaneously. In an effort to uncouple the reorganizations, we have used taxol, nocodazole, and the specific GSK3-β inhibitor DW12, to disrupt the dynamic microtubule network of differentiating cultures of the mouse skeletal muscle cell line C2. Despite strong effects on microtubules, cell shape and cell fusion, none of the treatments prevented early differentiation. Redistribution of centrosomal proteins, conditional on differentiation, was in fact increased by taxol and nocodazole and normal in DW12. Redistributions of Golgi complex and ER exit sites were incomplete but remained tightly linked under all circumstances, and conditional on centrosomal reorganization. We were therefore able to uncouple microtubule reorganization from the other events and to determine that centrosomal proteins lead the reorganization hierarchy. In addition, we have gained new insight into structural and functional aspects of the reorganization of microtubule nucleation during myogenesis.
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Affiliation(s)
- Kristien J M Zaal
- Light Imaging Section, Office of Science and Technology, National Institute of Arthritis, Musculoskeletal, and Skin Disease, National Institutes of Health, Bethesda, Maryland, USA.
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Mancini A, Sirabella D, Zhang W, Yamazaki H, Shirao T, Krauss RS. Regulation of myotube formation by the actin-binding factor drebrin. Skelet Muscle 2011; 1:36. [PMID: 22152295 PMCID: PMC3251523 DOI: 10.1186/2044-5040-1-36] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 12/08/2011] [Indexed: 11/15/2022] Open
Abstract
Background Myogenic differentiation involves cell-cycle arrest, activation of the muscle-specific transcriptome, and elongation, alignment and fusion of myoblasts into multinucleated myotubes. This process is controlled by promyogenic transcription factors and regulated by signaling pathways in response to extracellular cues. The p38 mitogen-activated protein kinase (p38 MAPK) pathway promotes the activity of several such transcription factors, including MyoD and MEF2, thereby controlling the muscle-specific transcription program. However, few p38-regulated genes that play a role in the regulation of myogenesis have been identified. Methods RNA interference (RNAi), chemical inhibition and immunofluorescence approaches were used to assess the role of drebrin in differentiation of primary mouse myoblasts and C2C12 cells. Results In a search for p38-regulated genes that promote myogenic differentiation, we identified Dbn1, which encodes the actin-binding protein drebrin. Drebrin is an F-actin side-binding protein that remodels actin to facilitate the change of filopodia into dendritic spines during synaptogenesis in developing neurons. Dbn1 mRNA and protein are induced during differentiation of primary mouse and C2C12 myoblasts, and induction is substantially reduced by the p38 MAPK inhibitor SB203580. Primary myoblasts and C2C12 cells depleted of drebrin by RNAi display reduced levels of myogenin and myosin heavy chain and form multinucleated myotubes very inefficiently. Treatment of myoblasts with BTP2, a small-molecule inhibitor of drebrin, produces a phenotype similar to that produced by knockdown of drebrin, and the inhibitory effects of BTP2 are rescued by expression of a mutant form of drebrin that is unable to bind BTP2. Drebrin in myoblasts is enriched in cellular projections and cell cortices and at regions of cell-cell contact, all sites where F-actin, too, was concentrated. Conclusions Our findings reveal that Dbn1 expression is a target of p38 MAPK signaling during myogenesis and that drebrin promotes myoblast differentiation.
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Affiliation(s)
- Annalisa Mancini
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, One Gustave L, Levy Place, New York, NY 10029, USA.
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Dobi KC, Metzger T, Baylies MK. Characterization of early steps in muscle morphogenesis in a Drosophila primary culture system. Fly (Austin) 2011; 5:68-75. [PMID: 21339707 DOI: 10.4161/fly.5.2.15031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Myogenesis in Drosophila embryos requires fusion between Founder cells (FCs) and Fusion Competent myoblasts (FCMs) to form multinucleate myotubes. Myoblast fusion is well characterized in embryos, and many factors required for this process have been identified; however, a number of questions pertaining to the mechanisms of fusion remain and are challenging to answer in the embryo. We have developed a modified primary cell culture protocol to address these questions in vitro. Using this system, we determined the optimal time for examining fusion in culture and confirmed that known fusion proteins are expressed and localized as in embryos. Importantly, we disrupted the actin and microtubule networks with the drugs latrunculin B and nocodazole, respectively, confirming that actin is required for myoblast fusion and showing for the first time that microtubules are also required for this process in Drosophila. Finally, we show that myotubes in culture adopt and maintain specific muscle identities.
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Affiliation(s)
- Krista C Dobi
- Memorial Sloan-Kettering Cancer Center; New York, NY, USA
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Picone R, Ren X, Ivanovitch KD, Clarke JDW, McKendry RA, Baum B. A polarised population of dynamic microtubules mediates homeostatic length control in animal cells. PLoS Biol 2010; 8:e1000542. [PMID: 21103410 PMCID: PMC2982804 DOI: 10.1371/journal.pbio.1000542] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 10/01/2010] [Indexed: 11/18/2022] Open
Abstract
An analysis of cells grown on micro-patterned lines, and of cells during zebrafish development, identifies a population of microtubules that align along the long axis of cells to mediate homeostatic length control. Because physical form and function are intimately linked, mechanisms that maintain cell shape and size within strict limits are likely to be important for a wide variety of biological processes. However, while intrinsic controls have been found to contribute to the relatively well-defined shape of bacteria and yeast cells, the extent to which individual cells from a multicellular animal control their plastic form remains unclear. Here, using micropatterned lines to limit cell extension to one dimension, we show that cells spread to a characteristic steady-state length that is independent of cell size, pattern width, and cortical actin. Instead, homeostatic length control on lines depends on a population of dynamic microtubules that lead during cell extension, and that are aligned along the long cell axis as the result of interactions of microtubule plus ends with the lateral cell cortex. Similarly, during the development of the zebrafish neural tube, elongated neuroepithelial cells maintain a relatively well-defined length that is independent of cell size but dependent upon oriented microtubules. A simple, quantitative model of cellular extension driven by microtubules recapitulates cell elongation on lines, the steady-state distribution of microtubules, and cell length homeostasis, and predicts the effects of microtubule inhibitors on cell length. Together this experimental and theoretical analysis suggests that microtubule dynamics impose unexpected limits on cell geometry that enable cells to regulate their length. Since cells are the building blocks and architects of tissue morphogenesis, such intrinsically defined limits may be important for development and homeostasis in multicellular organisms. Because many physical processes change with scale, size control is a fundamental problem for living systems. While in some instances the size of a structure is directly determined by the dimensions of its individual constituents, many biological structures are dynamic, self-organising assemblies of relatively small component parts. How such assemblies are maintained within defined size limits remains poorly understood. Here, by confining cells to spread on lines, we show that animal cells reach a defined length that is independent of their volume and width. In searching for a “ruler” that might determine this axial limit to cell spreading, we identified a population of dynamic microtubule polymers that become oriented along the long axis of cells. This growing population of oriented microtubules drives extension of the spreading cell margin while, conversely, interactions with the cell margin promote microtubule depolymerisation, leading to cell shortening. Using a mathematical model we show that this coupling of dynamic microtubule polymerisation and depolymerisation with directed cell elongation is sufficient to explain the limit to cell spreading and cell length homeostasis. Because microtubules appear to regulate cell length in a similar way in the developing zebrafish neural tube, we suggest that this microtubule-dependent mechanism is likely to be of widespread importance for the regulation of cell and tissue geometry.
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Affiliation(s)
- Remigio Picone
- Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, London, United Kingdom
- London Centre for Nanotechnology, London, United Kingdom
- Department of Medicine, University College London, London, United Kingdom
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Xiaoyun Ren
- Medical Research Council Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Kenzo D. Ivanovitch
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Jon D. W. Clarke
- Medical Research Council Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Rachel A. McKendry
- London Centre for Nanotechnology, London, United Kingdom
- Department of Medicine, University College London, London, United Kingdom
- * E-mail: (RAM); (BB)
| | - Buzz Baum
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- * E-mail: (RAM); (BB)
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49
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Whipple RA, Matrone MA, Cho EH, Balzer EM, Vitolo MI, Yoon JR, Ioffe OB, Tuttle KC, Yang J, Martin SS. Epithelial-to-mesenchymal transition promotes tubulin detyrosination and microtentacles that enhance endothelial engagement. Cancer Res 2010; 70:8127-37. [PMID: 20924103 DOI: 10.1158/0008-5472.can-09-4613] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Epithelial-to-mesenchymal transition (EMT) is associated with increased breast tumor metastasis; however, the specific mechanisms by which EMT promotes metastasis remain somewhat unclear. Despite the importance of cytoskeletal dynamics during both EMT and metastasis, very few current studies examine the cytoskeleton of detached and circulating tumor cells. Specific posttranslational α-tubulin modifications are critical for adherent cell motility and implicated in numerous pathologies, but also remain understudied in detached cells. We report here that EMT induced through ectopic expression of Twist or Snail promotes α-tubulin detyrosination and the formation of tubulin-based microtentacles in detached HMLEs. Mechanistically, EMT downregulates the tubulin tyrosine ligase enzyme, resulting in an accumulation of detyrosinated α-tubulin (Glu-tubulin), and increases microtentacles that penetrate endothelial layers to facilitate tumor cell reattachment. Confocal microscopy shows that microtentacles are capable of penetrating the junctions between endothelial cells. Suppression of endogenous Twist in metastatic human breast tumor cells is capable of reducing both tubulin detyrosination and microtentacles. Clinical breast tumor samples display high concordance between Glu-tubulin and Twist expression levels, emphasizing the coupling between EMT and tubulin detyrosination in vivo. Coordinated elevation of Twist and Glu-tubulin at invasive tumor fronts, particularly within ductal carcinoma in situ samples, establishes that EMT-induced tubulin detyrosination occurs at the earliest stages of tumor invasion. These data support a novel model where the EMT that occurs during tumor invasion downregulates tubulin tyrosine ligase, increasing α-tubulin detyrosination and promoting microtentacles that could enhance the reattachment of circulating tumor cells to the vascular endothelium during metastasis.
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Affiliation(s)
- Rebecca A Whipple
- Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Fant X, Srsen V, Espigat-Georger A, Merdes A. Nuclei of non-muscle cells bind centrosome proteins upon fusion with differentiating myoblasts. PLoS One 2009; 4:e8303. [PMID: 20011525 PMCID: PMC2788420 DOI: 10.1371/journal.pone.0008303] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 11/23/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In differentiating myoblasts, the microtubule network is reorganized from a centrosome-bound, radial array into parallel fibres, aligned along the long axis of the cell. Concomitantly, proteins of the centrosome relocalize from the pericentriolar material to the outer surface of the nucleus. The mechanisms that govern this relocalization are largely unknown. METHODOLOGY In this study, we perform experiments in vitro and in cell culture indicating that microtubule nucleation at the centrosome is reduced during myoblast differentiation, while nucleation at the nuclear surface increases. We show in heterologous cell fusion experiments, between cultures of differentiating mouse myoblasts and human cells of non-muscular origin, that nuclei from non-muscle cells recruit centrosome proteins once fused with the differentiating myoblasts. This recruitment still occurs in the presence of cycloheximide and thus appears to be independent of new protein biosynthesis. CONCLUSIONS Altogether, our data suggest that nuclei of undifferentiated cells have the dormant potential to bind centrosome proteins, and that this potential becomes activated during myoblast differentiation.
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Affiliation(s)
- Xavier Fant
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Vlastimil Srsen
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Aude Espigat-Georger
- Unité Mixte de Recherche 2587, Centre National de la Recherche Scientifique-Pierre Fabre, Toulouse, France
| | - Andreas Merdes
- Unité Mixte de Recherche 2587, Centre National de la Recherche Scientifique-Pierre Fabre, Toulouse, France
- * E-mail:
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