TY - JOUR T1 - Measurement of myofilament calcium in living cardiomyocytes using a targeted genetically encoded indicator JF - bioRxiv DO - 10.1101/268003 SP - 268003 AU - Paul Robinson AU - Alexander J Sparrow AU - Connor N Broyles AU - Kolja Sievert AU - Yu-Fen Chang AU - Frances A Brook AU - Xiaoyu Zhang AU - Hugh Watkins AU - Yama A Abassi AU - Michael A Geeves AU - Charles Redwood AU - Matthew J Daniels Y1 - 2018/01/01 UR - http://biorxiv.org/content/early/2018/04/16/268003.abstract N2 - Visualising when and where calcium appears and disappears in cardiomyocytes is a major goal of cardiovascular research. Surprisingly we find that the chemical dyes widely used for this purpose disrupt cell contractility, due at least in part due to direct inhibition of the acto-myosin ATPase required to generate force. In order to improve calcium detection methods, we have developed a genetically encoded indicator that sits within the myofilament to directly visualise the changes occurring at the sarcomere. This tool improves on established chemical dyes and untargeted genetically encoded indicators for analysing small molecule modulators of myofilament-based calcium signalling. Importantly this is achieved without any measurable change in contractile function. ER -