title: Calpain cleavage within dysferlin exon 40a releases a synaptotagmin-like module for membrane repair.
abstract: Dysferlin and calpain are important mediators of the emergency response to repair plasma membrane injury. Our previous research revealed that membrane injury induces cleavage of dysferlin to release a synaptotagmin-like C-terminal module we termed mini-dysferlinC72. Here we show that injury-activated cleavage of dysferlin is mediated by the ubiquitous calpains via a cleavage motif encoded by alternately spliced exon 40a. An exon 40a-specific antibody recognizing cleaved mini-dysferlinC72 intensely labels the circumference of injury sites, supporting a key role for dysferlinExon40a isoforms in membrane repair and consistent with our evidence suggesting that the calpain-cleaved C-terminal module is the form specifically recruited to injury sites. Calpain cleavage of dysferlin is a ubiquitous response to membrane injury in multiple cell lineages and occurs independently of the membrane repair protein MG53. Our study links calpain and dysferlin in the calcium-activated vesicle fusion of membrane repair, placing calpains as upstream mediators of a membrane repair cascade that elicits cleaved dysferlin as an effector. Of importance, we reveal that myoferlin and otoferlin are also cleaved enzymatically to release similar C-terminal modules, bearing two C2 domains and a transmembrane domain. Evolutionary preservation of this feature highlights its functional importance and suggests that this highly conserved C-terminal region of ferlins represents a functionally specialized vesicle fusion module.
authors.affiliation: Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia.
authors.forename: G M I
authors.initials: GM
authors.lastname: Redpath
authors.affiliation: Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia.
authors.forename: N
authors.initials: N
authors.lastname: Woolger
authors.affiliation: Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia.
authors.forename: A K
authors.initials: AK
authors.lastname: Piper
authors.affiliation: Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia.
authors.forename: F A
authors.initials: FA
authors.lastname: Lemckert
authors.affiliation: Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Lek
authors.affiliation: Department of Pathology and Molecular Medicine, Queen's University, Division of Cancer Biology and Genetics, Queen's Cancer Research Institute, Kingston, ON K7L 3N6, Canada.
authors.forename: P A
authors.initials: PA
authors.lastname: Greer
authors.affiliation: Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia, and Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, VIC 3010, Australia.
authors.forename: K N
authors.initials: KN
authors.lastname: North
authors.affiliation: Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia sandra.cooper@sydney.edu.au.
authors.forename: S T
authors.initials: ST
authors.lastname: Cooper
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002154:Calpain / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D000073939:Dysferlin; D057809:HEK293 Cells; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D008561:Membrane Fusion / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D050857:Synaptotagmins / Q000378:metabolism*; D000070584:Tripartite Motif Proteins
chemical_list: D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; C114839:DYSF protein, human; D000073939:Dysferlin; C415584:MYOF protein, human; D008565:Membrane Proteins; D009124:Muscle Proteins; C118457:OTOF protein, human; D020033:Protein Isoforms; C558399:TRIM72 protein, human; D000070584:Tripartite Motif Proteins; D050857:Synaptotagmins; D002154:Calpain; C410233:Capns1 protein, mouse; C570925:Capn2 protein, mouse