Ferlins are a novel class of membrane-bound proteins with six C2 domains. In other membrane associated proteins, C2 domains have been implicated in the regulation of membrane fusion by divalent cation and phospholipid binding, and through protein interactions. Mutations in the worm ferlin homolog, fer-1, produce defective membrane fusion. Mutations in dysferlin cause muscular dystrophy in humans. Dysferlin mutations produce an abnormal accumulation of subsarcolemmal vesicles in muscle. We identified myoferlin because of its high homology to dysferlin. We generated antibodies specific to dysferlin and myoferlin and found that each protein is associated with the plasma membrane. In prefusion myoblasts, myoferlin is highly expressed, while dysferlin is expressed in mature myotubes. We demonstrated that the C2A domain of dysferlin and myoferlin bound phosphotidylserine in a calcium-dependent manner. Furthermore, a mutation dysferlin that is associated with muscular dystrophy reduced calcium sensitive phospholipid binding. In muscle, membrane fusion is necessary for myoblast fusion to multinucleate myotubes. Membrane fusion is also required for membrane repair. We hypothesize that dysferlin and myoferlin regulate membrane fusion events in muscle. Moreover, we believe that defects in these ferlin proteins lead to abnormal membrane fusion. To elucidate the role of ferlin proteins in membrane fusion in muscle:
Aim 1) We will test the calcium sensitive phospholipid binding properties of normal and mutant ferlin C2 domains.
Aim 2) We will study the role of ferlin proteins in regeneration and repair in vivo using murine models of ferlin underexpression and ferlin overexpression.
Aim 3) We will characterize a novel ferlin.
Aim 4) We will search for ferlin- interacting proteins to determine additional proteins that regulate muscle membrane fusion. Significance: These experiments are designed to improve our understanding membrane fusion in muscle. Membrane fusion in muscle is relevant to diseases such as muscular dystrophy and also to the normal aging process of muscle. ? ?
|Quattrocelli, Mattia; Capote, Joanna; Ohiri, Joyce C et al. (2017) Genetic modifiers of muscular dystrophy act on sarcolemmal resealing and recovery from injury. PLoS Genet 13:e1007070|
|Quattrocelli, Mattia; Barefield, David Y; Warner, James L et al. (2017) Intermittent glucocorticoid steroid dosing enhances muscle repair without eliciting muscle atrophy. J Clin Invest 127:2418-2432|
|Demonbreun, Alexis R; McNally, Elizabeth M (2017) Muscle cell communication in development and repair. Curr Opin Pharmacol 34:7-14|
|Quattrocelli, Mattia; Salamone, Isabella M; Page, Patrick G et al. (2017) Intermittent Glucocorticoid Dosing Improves Muscle Repair and Function in Mice with Limb-Girdle Muscular Dystrophy. Am J Pathol 187:2520-2535|
|Demonbreun, Alexis R; McNally, Elizabeth M (2016) Plasma Membrane Repair in Health and Disease. Curr Top Membr 77:67-96|
|Demonbreun, Alexis R; Quattrocelli, Mattia; Barefield, David Y et al. (2016) An actin-dependent annexin complex mediates plasma membrane repair in muscle. J Cell Biol 213:705-18|
|Lamar, Kay-Marie; Miller, Tamari; Dellefave-Castillo, Lisa et al. (2016) Genotype-Specific Interaction of Latent TGF? Binding Protein 4 with TGF?. PLoS One 11:e0150358|
|Demonbreun, Alexis R; Allen, Madison V; Warner, James L et al. (2016) Enhanced Muscular Dystrophy from Loss of Dysferlin Is Accompanied by Impaired Annexin A6 Translocation after Sarcolemmal Disruption. Am J Pathol 186:1610-22|
|Lenhart, Kaitlin C; O'Neill 4th, Thomas J; Cheng, Zhaokang et al. (2015) GRAF1 deficiency blunts sarcolemmal injury repair and exacerbates cardiac and skeletal muscle pathology in dystrophin-deficient mice. Skelet Muscle 5:27|
|Demonbreun, Alexis R; McNally, Elizabeth M (2015) DNA Electroporation, Isolation and Imaging of Myofibers. J Vis Exp :e53551|
Showing the most recent 10 out of 30 publications