Mechanical forces are efficiently converted into cellular signals to initiate structural and functional remodeling of cardiac myocytes. Molecular mechanisms underlying cardiac mechanotransduction are still barely understood. Nuclear Factor of Activated T-cells (NFAT) is an important calcium-responsive transcription factor and a key player in cardiac remodeling processes. In this study, we investigated the involvement of Ca2+ signaling molecules as a link between mechanical stretch and NFAT translocation in HL-1 atrial myocytes. We specifically focused on the potential role of receptor-operated and/or store-operated Ca2+ permeable channels of the TRPCs (classical transient receptor potential) and the Orai family. Populations of HL-1 cells overexpressing GFP-NFAT were exposed to a single-stretch by 20% for 20 minutes on commercially available silicon membranes and NFAT localization was then analyzed by fluorescence microscopy. Results revealed that stretched HL-1 cells significantly increased NFAT nuclear translocation when compared to unstretched cells. Similar NFAT activation was obtained when HL-1 cells were stimulated by either endothelin-1 (100 nM) or thapsigargin (1μM) in the absence of a stretch stimulus. These results demonstrate that similar levels of NFAT activation are induced in HL-1 cells by either mechanical stress, cell activation via Gq-coupled receptors or depletion of internal Ca2+ stores. HL-1 cells were found to express several TRPC isoforms that might contribute to mechanotransduction. Our data suggest a linkage between mechanical stretch and cardiac remodeling involving Ca2+ entry and NFAT activation.This work is funded by FWF (Austrian research fund) projects P21925-B19, P22565-B18 and the DK Metabolic and Cardiovascular Disease grant W1226-B18.