Study of a multiprotein complex involved in excitation‐transcription coupling in skeletal cells (1164.9)

Abstract

Pannexin‐1 (Panx1) releases ATP to the extracellular space in skeletal muscle cells in response to electrical stimulation. ATP is a relevant mediator between membrane depolarization and gene expression. We propose that this signaling pathway would require the proper coordination between the voltage sensor (dihydropyridine receptor, DHPR), pannexin1 channels (PnX1, ATP release conduit), nucleotide receptors, and several signaling molecules. The goal of this study was to assess protein‐protein interactions within the E‐T machinery in several models. Newborn derived myotubes, adult fibers, triad fractions from rat or mouse skeletal muscles and L6 cells overexpressing PnX1 have been used. In all the models co‐immunoprecipitation between DHPR, PnX1, P2Y2 receptor and dystrophin has been detected. Using 2D blue‐native SDS/PAGE we detected that DHPR, PnX1, P2Y2, caveolin3 and dystrophin belong to the same multiprotein complex. Using the proximity ligation assay associated to confocal microscopy, we observed co‐localization between DHPR, PnX1, P2Y2 and caveolin3. Unveiling the molecular actors involved in the regulation of gene expression could contribute to the understanding and treatment of skeletal muscle disorders such as muscular dystrophies and sarcopenia associated with aging. Grant Funding Source: Supported by Fondecyt‐1110467‐11100454, Conicyt‐79090021, FONDAP‐15010006, ACT‐1111