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Wherley TJ, Thomas S, Millay DP, Saunders T, Roy S. Molecular regulation of myocyte fusion. Curr Top Dev Biol 2024; 158:53-82. [PMID: 38670716 DOI: 10.1016/bs.ctdb.2024.01.016] [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] [Indexed: 04/28/2024]
Abstract
Myocyte fusion is a pivotal process in the development and regeneration of skeletal muscle. Failure during fusion can lead to a range of developmental as well as pathological consequences. This review aims to comprehensively explore the intricate processes underlying myocyte fusion, from the molecular to tissue scale. We shed light on key players, such as the muscle-specific fusogens - Myomaker and Myomixer, in addition to some lesser studied molecules contributing to myocyte fusion. Conserved across vertebrates, Myomaker and Myomixer play a crucial role in driving the merger of plasma membranes of fusing myocytes, ensuring the formation of functional muscle syncytia. Our multiscale approach also delves into broader cell and tissue dynamics that orchestrate the timing and positioning of fusion events. In addition, we explore the relevance of muscle fusogens to human health and disease. Mutations in fusogen genes have been linked to congenital myopathies, providing unique insights into the molecular basis of muscle diseases. We conclude with a discussion on potential therapeutic avenues that may emerge from manipulating the myocyte fusion process to remediate skeletal muscle disorders.
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Affiliation(s)
- Tanner J Wherley
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Serena Thomas
- Warwick Medical School, University of Warwick, Coventry, United Kingdom; Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Proteos, Singapore, Singapore
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States.
| | - Timothy Saunders
- Warwick Medical School, University of Warwick, Coventry, United Kingdom; Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Proteos, Singapore, Singapore.
| | - Sudipto Roy
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Proteos, Singapore, Singapore; Department of Biological Sciences, National University of Singapore, Singapore, Singapore; Department of Pediatrics, National University of Singapore, Singapore, Singapore.
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Johnson CJ, Zhang Z, Zhang H, Shang R, Piekarz KM, Bi P, Stolfi A. A change in cis-regulatory logic underlying obligate versus facultative muscle multinucleation in chordates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.06.583753. [PMID: 38559144 PMCID: PMC10979880 DOI: 10.1101/2024.03.06.583753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Vertebrates and tunicates are sister groups that share a common fusogenic factor, Myomaker (Mymk), that drives myoblast fusion and muscle multinucleation. Yet they are divergent in when and where they express Mymk. In vertebrates, all developing skeletal muscles express Mymk and are obligately multinucleated. In tunicates, Mymk is only expressed in post-metamorphic multinucleated muscles, but is absent from mononucleated larval muscles. In this study, we demonstrate that cis-regulatory sequence differences in the promoter region of Mymk underlie the different spatiotemporal patterns of its transcriptional activation in tunicates and vertebrates. While in vertebrates Myogenic Regulatory Factors (MRFs) like MyoD1 alone are required and sufficient for Mymk transcription in all skeletal muscles, we show that transcription of Mymk in post-metamorphic muscles of the tunicate Ciona requires the combinatorial activity of MRF/MyoD and Early B-Cell Factor (Ebf). This macroevolutionary difference appears to be encoded in cis, likely due to the presence of a putative Ebf binding site adjacent to predicted MRF binding sites in the Ciona Mymk promoter. We further discuss how Mymk and myoblast fusion might have been regulated in the last common ancestor of tunicates and vertebrates, for which we propose two models.
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Affiliation(s)
| | - Zheng Zhang
- Department of Genetics, University of Georgia, Athens, GA, USA
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - Haifeng Zhang
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - Renjie Shang
- Department of Genetics, University of Georgia, Athens, GA, USA
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - Katarzyna M Piekarz
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Pengpeng Bi
- Department of Genetics, University of Georgia, Athens, GA, USA
- Center for Molecular Medicine, University of Georgia, Athens, GA, USA
| | - Alberto Stolfi
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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Wuyun Q, Chen Y, Shen Y, Cao Y, Hu G, Cui W, Gao J, Zheng W. Recent Progress of Protein Tertiary Structure Prediction. Molecules 2024; 29:832. [PMID: 38398585 PMCID: PMC10893003 DOI: 10.3390/molecules29040832] [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: 12/30/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
The prediction of three-dimensional (3D) protein structure from amino acid sequences has stood as a significant challenge in computational and structural bioinformatics for decades. Recently, the widespread integration of artificial intelligence (AI) algorithms has substantially expedited advancements in protein structure prediction, yielding numerous significant milestones. In particular, the end-to-end deep learning method AlphaFold2 has facilitated the rise of structure prediction performance to new heights, regularly competitive with experimental structures in the 14th Critical Assessment of Protein Structure Prediction (CASP14). To provide a comprehensive understanding and guide future research in the field of protein structure prediction for researchers, this review describes various methodologies, assessments, and databases in protein structure prediction, including traditionally used protein structure prediction methods, such as template-based modeling (TBM) and template-free modeling (FM) approaches; recently developed deep learning-based methods, such as contact/distance-guided methods, end-to-end folding methods, and protein language model (PLM)-based methods; multi-domain protein structure prediction methods; the CASP experiments and related assessments; and the recently released AlphaFold Protein Structure Database (AlphaFold DB). We discuss their advantages, disadvantages, and application scopes, aiming to provide researchers with insights through which to understand the limitations, contexts, and effective selections of protein structure prediction methods in protein-related fields.
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Affiliation(s)
- Qiqige Wuyun
- Department of Computer Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Yihan Chen
- School of Mathematical Sciences and LPMC, Nankai University, Tianjin 300071, China;
| | - Yifeng Shen
- Faculty of Environment and Information Studies, Keio University, Fujisawa 252-0882, Kanagawa, Japan;
| | - Yang Cao
- College of Life Sciences, Sichuan University, Chengdu 610065, China
| | - Gang Hu
- NITFID, School of Statistics and Data Science, LPMC and KLMDASR, Nankai University, Tianjin 300071, China
| | - Wei Cui
- School of Mathematical Sciences and LPMC, Nankai University, Tianjin 300071, China;
| | - Jianzhao Gao
- School of Mathematical Sciences and LPMC, Nankai University, Tianjin 300071, China;
| | - Wei Zheng
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
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Long T, Zhang Y, Donnelly L, Li H, Pien YC, Liu N, Olson EN, Li X. Cryo-EM structures of Myomaker reveal a molecular basis for myoblast fusion. Nat Struct Mol Biol 2023; 30:1746-1754. [PMID: 37770716 DOI: 10.1038/s41594-023-01110-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 08/25/2023] [Indexed: 09/30/2023]
Abstract
The fusion of mononucleated myoblasts produces multinucleated muscle fibers leading to the formation of skeletal muscle. Myomaker, a skeletal muscle-specific membrane protein, is essential for myoblast fusion. Here we report the cryo-EM structures of mouse Myomaker (mMymk) and Ciona robusta Myomaker (cMymk). Myomaker contains seven transmembrane helices (TMs) that adopt a G-protein-coupled receptor-like fold. TMs 2-4 form a dimeric interface, while TMs 3 and 5-7 create a lipid-binding site that holds the polar head of a phospholipid and allows the alkyl tails to insert into Myomaker. The similarity of cMymk and mMymk suggests a conserved Myomaker-mediated cell fusion mechanism across evolutionarily distant species. Functional analyses demonstrate the essentiality of the dimeric interface and the lipid-binding site for fusogenic activity, and heterologous cell-cell fusion assays show the importance of transcellular interactions of Myomaker protomers for myoblast fusion. Together, our findings provide structural and functional insights into the process of myoblast fusion.
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Affiliation(s)
- Tao Long
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yichi Zhang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Linda Donnelly
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hui Li
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yu-Chung Pien
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ning Liu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Xiaochun Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Tang Q, Liu M, Zhao H, Chen L. Glycogen-binding protein STBD1: Molecule and role in pathophysiology. J Cell Physiol 2023; 238:2010-2025. [PMID: 37435888 DOI: 10.1002/jcp.31078] [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: 02/21/2023] [Revised: 06/19/2023] [Accepted: 06/23/2023] [Indexed: 07/13/2023]
Abstract
Starch-binding domain-containing protein 1 (STBD1) is a glycogen-binding protein discovered in skeletal muscle gene differential expression that is pivotal to cellular energy metabolism. Recent studies have indicated that STBD1 is involved in many physiological processes, such as glycophagy, glycogen accumulation, and lipid droplet formation. Moreover, dysregulation of STBD1 causes multiple diseases, including cardiovascular disease, metabolic disease, and even cancer. Deletions and/or mutations in STBD1 promote tumorigenesis. Therefore, STBD1 has garnered considerable interest in the pathology community. In this review, we first summarized the current understanding of STBD1, including its structure, subcellular localization, tissue distribution, and biological functions. Next, we examined the roles and molecular mechanisms of STBD1 in related diseases. Based on available research, we discussed the novel function and future of STBD1, including its potential application as a therapeutic target in glycogen-related diseases. Given the significance of STBD1 in energy metabolism, an in-depth understanding of the protein is crucial for understanding physiological processes and developing therapeutic strategies for related diseases.
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Affiliation(s)
- Qiannan Tang
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Hengyang Medical School, University of South China, Hengyang, China
| | - Meiqing Liu
- Key Laboratory of Cardiovascular Diseases of Yunnan Province, Key Laboratory of Tumor Immunological Prevention and Treatment of Yunnan Province, Central Laboratory of Yan'an Hospital Affiliated to Kunming Medical University, Kunming, China
| | - Hong Zhao
- Nursing College, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Linxi Chen
- Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Hengyang Medical School, University of South China, Hengyang, China
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Witcher PC, Sun C, Millay DP. Expression of Myomaker and Myomerger in myofibers causes muscle pathology. Skelet Muscle 2023; 13:8. [PMID: 37127758 PMCID: PMC10150476 DOI: 10.1186/s13395-023-00317-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 04/17/2023] [Indexed: 05/03/2023] Open
Abstract
BACKGROUND Skeletal muscle development and regeneration depend on cellular fusion of myogenic progenitors to generate multinucleated myofibers. These progenitors utilize two muscle-specific fusogens, Myomaker and Myomerger, which function by remodeling cell membranes to fuse to each other or to existing myofibers. Myomaker and Myomerger expression is restricted to differentiating progenitor cells as they are not detected in adult myofibers. However, Myomaker remains expressed in myofibers from mice with muscular dystrophy. Ablation of Myomaker from dystrophic myofibers results in reduced membrane damage, leading to a model where persistent fusogen expression in myofibers, in contrast to myoblasts, is harmful. METHODS Dox-inducible transgenic mice were developed to ectopically express Myomaker or Myomerger in the myofiber compartment of skeletal muscle. We quantified indices of myofiber membrane damage, such as serum creatine kinase and IgM+ myofibers, and assessed general muscle histology, including central nucleation, myofiber size, and fibrosis. RESULTS Myomaker or Myomerger expression in myofibers independently caused membrane damage at acute time points. This damage led to muscle pathology, manifesting with centrally nucleated myofibers and muscle atrophy. Dual expression of both Myomaker and Myomerger in myofibers exacerbated several aspects of muscle pathology compared to expression of either fusogen by itself. CONCLUSIONS These data reveal that while myofibers can tolerate some level of Myomaker and Myomerger, expression of a single fusogen above a threshold or co-expression of both fusogens is damaging to myofibers. These results explain the paradigm that their expression in myofibers can have deleterious consequences in muscle pathologies and highlight the need for their highly restricted expression during myogenesis and fusion.
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Affiliation(s)
- Phillip C Witcher
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Chengyi Sun
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA.
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