title: Dystrophin/α1-syntrophin scaffold regulated PLC/PKC-dependent store-operated calcium entry in myotubes.
abstract: In skeletal muscles from patient suffering of Duchenne Muscular Dystrophy and from mdx mice, the absence of the cytoskeleton protein dystrophin has been shown to be essential for maintaining a normal calcium influx. We showed that a TRPC store-dependent cation influx is increased by loss of dystrophin or a scaffolding protein α1-syntrophin, however the mechanisms of this calcium mishandling are incompletely understood. First of all, we confirmed that TRPC1 but also STIM1 and Orai1 are supporting the store-operated cation entry which is enhanced in dystrophin-deficient myotubes. Next, we demonstrated that inhibition of PLC or PKC in dystrophin-deficient myotubes restores elevated cation entry to normal levels similarly to enforced minidystrophin expression. In addition, silencing α1-syntrophin also increased cation influx in a PLC/PKC dependent pathway. We also showed that α1-syntrophin and PLCβ are part of a same protein complex reinforcing the idea of their inter-relation in calcium influx regulation. This elevated cation entry was decreased to normal levels by chelating intracellular free calcium with BAPTA-AM. Double treatments with BAPTA-AM and PLC or PKC inhibitors suggested that the elevation of cation influx by PLC/PKC pathway is dependent on cytosolic calcium. All these results demonstrate an involvement in dystrophin-deficient myotubes of a specific calcium/PKC/PLC pathway in elevation of store-operated cation influx supported by the STIM1/Orai1/TRPC1 proteins, which is normally regulated by the α1-syntrophin/dystrophin scaffold.
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, Université de Poitiers/CNRS, Poitiers, France.
authors.forename: Jessica
authors.initials: J
authors.lastname: Sabourin
authors.forename: Rania
authors.initials: R
authors.lastname: Harisseh
authors.forename: Thomas
authors.initials: T
authors.lastname: Harnois
authors.forename: Christophe
authors.initials: C
authors.lastname: Magaud
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bourmeyster
authors.forename: Nadine
authors.initials: N
authors.lastname: Déliot
authors.forename: Bruno
authors.initials: B
authors.lastname: Constantin
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002135:Calcium-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002614:Chelating Agents / Q000494:pharmacology; D016189:Dystrophin / Q000235:genetics / Q000378:metabolism*; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D009124:Muscle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000071740:ORAI1 Protein; D054799:Phospholipase C beta / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D000071737:Stromal Interaction Molecule 1; D050052:TRPC Cation Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D002135:Calcium-Binding Proteins; D002614:Chelating Agents; D016189:Dystrophin; D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D000071740:ORAI1 Protein; C520430:Orai1 protein, mouse; D034741:RNA, Small Interfering; C100757:Stim1 protein, mouse; D000071737:Stromal Interaction Molecule 1; D050052:TRPC Cation Channels; C091825:syntrophin alpha1; C096351:transient receptor potential cation channel, subfamily C, member 1; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D011493:Protein Kinase C; D054799:Phospholipase C beta; D002118:Calcium