title: Dysferlin-peptides reallocate mutated dysferlin thereby restoring function.
abstract: Mutations in the dysferlin gene cause the most frequent adult-onset limb girdle muscular dystrophy, LGMD2B. There is no therapy. Dysferlin is a membrane protein comprised of seven, beta-sheet enriched, C2 domains and is involved in Ca(2+)dependent sarcolemmal repair after minute wounding. On the protein level, point mutations in DYSF lead to misfolding, aggregation within the endoplasmic reticulum, and amyloidogenesis. We aimed to restore functionality by relocating mutant dysferlin. Therefore, we designed short peptides derived from dysferlin itself and labeled them to the cell penetrating peptide TAT. By tracking fluorescently labeled short peptides we show that these dysferlin-peptides localize in the endoplasmic reticulum. There, they are capable of reducing unfolded protein response stress. We demonstrate that the mutant dysferlin regains function in membrane repair in primary human myotubes derived from patients' myoblasts by the laser wounding assay and a novel technique to investigate membrane repair: the interventional atomic force microscopy. Mutant dysferlin abuts to the sarcolemma after peptide treatment. The peptide-mediated approach has not been taken before in the field of muscular dystrophies. Our results could redirect treatment efforts for this condition.
authors.affiliation: Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and Max Delbrück Center for Molecular Medicine, Berlin, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Schoewel
authors.forename: Andreas
authors.initials: A
authors.lastname: Marg
authors.forename: Severine
authors.initials: S
authors.lastname: Kunz
authors.forename: Tim
authors.initials: T
authors.lastname: Overkamp
authors.forename: Romy Siegert
authors.initials: RS
authors.lastname: Carrazedo
authors.forename: Ute
authors.initials: U
authors.lastname: Zacharias
authors.forename: Peter T
authors.initials: PT
authors.lastname: Daniel
authors.forename: Simone
authors.initials: S
authors.lastname: Spuler
mesh_terms: D058227:Amyloidogenic Proteins / Q000378:metabolism; D000818:Animals; D001706:Biopsy / Q000379:methods; D002118:Calcium / Q000737:chemistry; D000073939:Dysferlin; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005456:Fluorescent Dyes / Q000494:pharmacology; D006801:Humans; D007834:Lasers; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology*; D051379:Mice; D018625:Microscopy, Atomic Force / Q000379:methods; D009124:Muscle Proteins / Q000235:genetics* / Q000502:physiology*; D009154:Mutation; D020125:Mutation, Missense; D032446:Myoblasts / Q000166:cytology; D010455:Peptides / Q000737:chemistry; D017354:Point Mutation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D056811:Unfolded Protein Response
chemical_list: D058227:Amyloidogenic Proteins; C114839:DYSF protein, human; C497505:Dysf protein, mouse; D000073939:Dysferlin; D005456:Fluorescent Dyes; D008565:Membrane Proteins; D009124:Muscle Proteins; D010455:Peptides; D002118:Calcium