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Leikina E, Gamage DG, Prasad V, Goykhberg J, Crowe M, Diao J, Kozlov MM, Chernomordik LV, Millay DP. Myomaker and Myomerger Work Independently to Control Distinct Steps of Membrane Remodeling during Myoblast Fusion. Dev Cell 2018; 46:767-780.e7. [PMID: 30197239 DOI: 10.1016/j.devcel.2018.08.006] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/27/2018] [Accepted: 08/08/2018] [Indexed: 02/03/2023]
Abstract
Classic mechanisms for membrane fusion involve transmembrane proteins that assemble into complexes and dynamically alter their conformation to bend membranes, leading to mixing of membrane lipids (hemifusion) and fusion pore formation. Myomaker and Myomerger govern myoblast fusion and muscle formation but are structurally divergent from traditional fusogenic proteins. Here, we show that Myomaker and Myomerger independently mediate distinct steps in the fusion pathway, where Myomaker is involved in membrane hemifusion and Myomerger is necessary for fusion pore formation. Mechanistically, we demonstrate that Myomerger is required on the cell surface where its ectodomains stress membranes. Moreover, we show that Myomerger drives fusion completion in a heterologous system independent of Myomaker and that a Myomaker-Myomerger physical interaction is not required for function. Collectively, our data identify a stepwise cell fusion mechanism in myoblasts where different proteins are delegated to perform unique membrane functions essential for membrane coalescence.
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Affiliation(s)
- Evgenia Leikina
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dilani G Gamage
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Vikram Prasad
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Joanna Goykhberg
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michael Crowe
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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