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Orai1 Deficiency Leads To Heart Failure And Skeletal Myopathy In Zebrafish., Mirko Völkers, Nima Dolatabadi, Natalie Gude, Patrick Most, Mark A Sussman, David Hassel

Center for Translational Medicine Faculty Papers

Mutations in the store-operated Ca²⁺ entry pore protein ORAI1 have been reported to cause myopathies in human patients but the mechanism involved is not known. Cardiomyocytes express ORAI1 but its role in heart function is also unknown. Using reverse genetics in zebrafish, we demonstrated that inactivation of the highly conserved zebrafish orthologue of ORAI1 resulted in severe heart failure, reduced ventricular systolic function, bradycardia and skeletal muscle weakness. Electron microscopy of Orai1-deficient myocytes revealed progressive skeletal muscle instability with loss of myofiber integrity and ultrastructural abnormalities of the z-disc in both skeletal and cardiac muscle. Isolated Orai1-deficient cardiomyocytes showed loss …