title: Regulation of TRPC1 and TRPC4 cation channels requires an alpha1-syntrophin-dependent complex in skeletal mouse myotubes.
abstract: The dystrophin-associated protein complex (DAPC) is essential for skeletal muscle, and the lack of dystrophin in Duchenne muscular dystrophy results in a reduction of DAPC components such as syntrophins and in fiber necrosis. By anchoring various molecules, the syntrophins may confer a role in cell signaling to the DAPC. Calcium disorders and abnormally elevated cation influx in dystrophic muscle cells have suggested that the DAPC regulates some sarcolemmal cationic channels. We demonstrated previously that mini-dystrophin and alpha1-syntrophin restore normal cation entry in dystrophin-deficient myotubes and that sarcolemmal TRPC1 channels associate with dystrophin and the bound PDZ domain of alpha1-syntrophin. This study shows that small interfering RNA (siRNA) silencing of alpha1-syntrophin dysregulated cation influx in myotubes. Moreover, deletion of the PDZ-containing domain prevented restoration of normal cation entry by alpha1-syntrophin transfection in dystrophin-deficient myotubes. TRPC1 and TRPC4 channels are expressed at the sarcolemma of muscle cells; forced expression or siRNA silencing showed that cation influx regulated by alpha1-syntrophin is supported by TRPC1 and TRPC4. A molecular association was found between TRPC1 and TRPC4 channels and the alpha1-syntrophin-dystrophin complex. TRPC1 and TRPC4 channels may form sarcolemmal channels anchored to the DAPC, and alpha1-syntrophin is necessary to maintain the normal regulation of TRPC-supported cation entry in skeletal muscle. Cation channels with DAPC form a signaling complex that modulates cation entry and may be crucial for normal calcium homeostasis in skeletal muscles.
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, UMR CNRS 6187, Université de Poitiers, 86022 Poitiers, France.
authors.forename: Jessica
authors.initials: J
authors.lastname: Sabourin
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, UMR CNRS 6187, Université de Poitiers, 86022 Poitiers, France.
authors.forename: Coralie
authors.initials: C
authors.lastname: Lamiche
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, UMR CNRS 6187, Université de Poitiers, 86022 Poitiers, France.
authors.forename: Aurelie
authors.initials: A
authors.lastname: Vandebrouck
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, UMR CNRS 6187, Université de Poitiers, 86022 Poitiers, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Magaud
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, UMR CNRS 6187, Université de Poitiers, 86022 Poitiers, France.
authors.forename: Jerome
authors.initials: J
authors.lastname: Rivet
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, UMR CNRS 6187, Université de Poitiers, 86022 Poitiers, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Cognard
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, UMR CNRS 6187, Université de Poitiers, 86022 Poitiers, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bourmeyster
authors.affiliation: Institut de Physiologie et Biologie Cellulaires, UMR CNRS 6187, Université de Poitiers, 86022 Poitiers, France. Electronic address: bruno.constantin@univ-poitiers.fr.
authors.forename: Bruno
authors.initials: B
authors.lastname: Constantin
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002412:Cations / Q000378:metabolism; D002460:Cell Line; D049028:Dystrophin-Associated Protein Complex / Q000235:genetics / Q000378:metabolism; D020868:Gene Silencing; D006706:Homeostasis / Q000502:physiology*; D017136:Ion Transport / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering; D012508:Sarcolemma / Q000235:genetics / Q000378:metabolism; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D002412:Cations; D049028:Dystrophin-Associated Protein Complex; D008565:Membrane Proteins; D009124:Muscle Proteins; D034741:RNA, Small Interfering; D050052:TRPC Cation Channels; C489571:TRPC4 ion channel; C091825:syntrophin alpha1; C096351:transient receptor potential cation channel, subfamily C, member 1; D002118:Calcium