title: Regulation of capacitative calcium entries by alpha1-syntrophin: association of TRPC1 with dystrophin complex and the PDZ domain of alpha1-syntrophin.
abstract: Calcium mishandling in Duchenne dystrophic muscle suggested that dystrophin, a membrane-associated cytoskeleton protein, might regulate calcium signaling cascade such as calcium influx pathway. It was previously shown that abnormal calcium entries involve uncontrolled stretch-activated currents and store-operated Ca2+ currents supported by TRPC1 channels. Moreover, our recent work demonstrated that reintroduction of minidystrophin in dystrophic myotubes restores normal capacitative calcium entries (CCEs). However, until now, no molecular link between the dystrophin complex and calcium entry channels has been described. This study is the first to show by coimmunoprecipitation assays the molecular association of TRPC1 with dystrophin and alpha1-syntrophin in muscle cells. TRPC1 was also associated with alpha1-syntrophin in dystrophic muscle cells independently of dystrophin. Furthermore, glutathione S-transferase (GST) pull-down assays showed that TRPC1 binds to the alpha1-syntrophin PDZ domain. Transfected recombinant alpha1-syntrophin formed a complex with TRPC1 channels and restored normal CCEs in dystrophic muscle cells. We suggest that normal regulation of CCEs in skeletal muscle depends on the association between TRPC1 channels and alpha1-syntrophin that may anchor the store-operated channels to the dystrophin-associated protein complex (DAPC). The loss of this molecular association could participate in the calcium alterations observed in dystrophic muscle cells. This study provides a new model for the regulation of calcium influx by interaction with the scaffold of the DAPC in muscle cells.
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, CNRS, UMR-6187, University of Poitiers, 86022 Poitiers, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Vandebrouck
authors.forename: Jessica
authors.initials: J
authors.lastname: Sabourin
authors.forename: Jérôme
authors.initials: J
authors.lastname: Rivet
authors.forename: Haouria
authors.initials: H
authors.lastname: Balghi
authors.forename: Stéphane
authors.initials: S
authors.lastname: Sebille
authors.forename: Alain
authors.initials: A
authors.lastname: Kitzis
authors.forename: Guy
authors.initials: G
authors.lastname: Raymond
authors.forename: Christian
authors.initials: C
authors.lastname: Cognard
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bourmeyster
authors.forename: Bruno
authors.initials: B
authors.lastname: Constantin
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003599:Cytoskeleton / Q000378:metabolism; D016189:Dystrophin / Q000378:metabolism*; D049029:Dystrophin-Associated Proteins / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D047468:Immunoprecipitation; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012508:Sarcolemma / Q000378:metabolism; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D016189:Dystrophin; D049029:Dystrophin-Associated Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D011993:Recombinant Fusion Proteins; D050052:TRPC Cation Channels; C091825:syntrophin alpha1; C096351:transient receptor potential cation channel, subfamily C, member 1; D049452:Green Fluorescent Proteins; D002118:Calcium