The endocytic recycling protein EHD2 interacts with myoferlin to regulate myoblast fusion.
Skeletal muscle is a multinucleated syncytium that develops and is maintained by the fusion of myoblasts to the syncytium. Myoblast fusion involves the regulated coalescence of two apposed membranes. Myoferlin is a membrane-anchored, multiple C2 domain-containing protein that is highly expressed in fusing myoblasts and required for efficient myoblast fusion to myotubes. We found that myoferlin binds directly to the eps15 homology domain protein, EHD2. Members of the EHD family have been previously implicated in endocytosis as well as endocytic recycling, a process where membrane proteins internalized by endocytosis are returned to the plasma membrane. EHD2 binds directly to the second C2 domain of myoferlin, and EHD2 is reduced in myoferlin null myoblasts. In contrast to normal myoblasts, myoferlin null myoblasts accumulate labeled transferrin and have delayed recycling. Introduction of dominant negative EHD2 into myoblasts leads to the sequestration of myoferlin and inhibition of myoblast fusion. The interaction of myoferlin with EHD2 identifies molecular overlap between the endocytic recycling pathway and the machinery that regulates myoblast membrane fusion.
Doherty
Katherine R
KR
Department of Molecular Genetics and Cell Biology, Committee on Developmental Biology, The University of Chicago, Chicago, IL 60637, USA.
Demonbreun
Alexis R
AR
Wallace
Gregory Q
GQ
Cave
Andrew
A
Posey
Avery D
AD
Heretis
Konstantina
K
Pytel
Peter
P
McNally
Elizabeth M
EM
D000595:Amino Acid Sequence; D000818:Animals; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002459:Cell Fusion; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D017124:Conserved Sequence; D004705:Endocytosis; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D032446:Myoblasts / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D014168:Transferrin / Q000378:metabolism
D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; C485117:EHD2 protein, mouse; C415584:MYOF protein, human; D008565:Membrane Proteins; D009124:Muscle Proteins; D014168:Transferrin; C521810:myoferlin protein, mouse