1:00pm, Monday, 22 August
Room BIG13, Ground Floor
710 Cumberland St
Dr Michelle Munro
Department of Physiology, University of Otago
‘Cardiac ultrastructure, remodeling and calcium handling in heart health and disease’
The generation of a regular heartbeat relies on the signaling of calcium throughout the cardiomyocytes, which needs to be synchronised both within and between cells for efficient contraction of the heart. Structurally, this synchronisation is aided by the presence of invaginations of the plasma membrane throughout the cell, known as transverse tubules (t-tubules). One of the key proteins involved in cardiac calcium signaling is the ryanodine receptor – RyR. RyR is a calcium channel which releases calcium from the intracellular calcium store – the sarcoplasmic reticulum (SR). In healthy conditions, this creates the cell-wide increase in cytosolic calcium needed for cellular contraction. In cardiomyocytes, RyR form clusters at the dyad, a region formed by the close association of the SR and t-tubule membranes. In many forms of cardiomyopathy, t-tubule and dyad organisation becomes disrupted, and RyR function is dysregulated. This can result in reduced contractility of the heart or the generation of arrhythmias. This seminar will cover how RyR and dyadic organisation are altered in heart disease and contribute to altered calcium handling. This will include the application of different imaging techniques, including multi-colour confocal and super-resolution imaging.