The formation of skeletal muscle during embryonic development and following injury to adult muscle requires fusion of myoblasts to form multinucleated myofibers. Recently, we discovered a novel muscle-specific membrane protein, named Myomaker, that controls vertebrate myoblast fusion during embryogenesis and adulthood. Myomaker is expressed on the cell surface of embryonic myoblasts during fusion and is down- regulated thereafter. Similarly, Myomaker is up-regulated in muscle satellite cells in response to injury, concomitant with their fusion during muscle regeneration. Over-expression of Myomaker in myoblasts dramatically enhances fusion and forced expression in fibroblasts promotes fusion with myoblasts. Conversely, genetic disruption of Myomaker in mice causes perinatal death due to an absence of multi- nucleated muscle fibers and conditional gene deletion in adult satellite cells completely prevents muscle regeneration. The discovery of Myomaker provides a new inroad into myoblast fusion and will enable the detailed molecular dissection of the mechanistic basis of this process. Myomaker belongs to a small family of related membrane proteins that are expressed in other cell types, suggesting a general mechanism for cell-cell fusion. The goals of this project are to define the precise molecular mechanism whereby Myomaker drives myoblast fusion and to identify additional components of the process through which Myomaker exerts its fusogenic activity. The insights gleaned from these studies will shed light not only on the fundamental mechanisms of intercellular fusion but will also have important implications for understanding muscle disease and for the potential development of new therapeutic strategies for restoration of function to diseased muscle.

Public Health Relevance

Skeletal muscle formation during development and following injury requires fusion of muscle cells to form multinucleated myofibers. We recently discovered a muscle-specific membrane protein, named Myomaker, that controls muscle cell fusion and the goal of this project is to define the molecular basis of myoblast fusion and muscle formation under the control of Myomaker. The insights gleaned from these studies will shed light not only on the fundamental mechanisms of intercellular fusion but will also have important implications for understanding muscle disease and for the potential development of new therapeutic strategies for restoration of function to diseased muscle.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
1R01AR067294-01A1
Application #
8961360
Study Section
Skeletal Muscle and Exercise Physiology Study Section (SMEP)
Program Officer
Boyce, Amanda T
Project Start
2015-07-15
Project End
2020-06-30
Budget Start
2015-07-15
Budget End
2016-06-30
Support Year
1
Fiscal Year
2015
Total Cost
$350,347
Indirect Cost
$130,347
Name
University of Texas Sw Medical Center Dallas
Department
Biochemistry
Type
Schools of Medicine
DUNS #
800771545
City
Dallas
State
TX
Country
United States
Zip Code
75390
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