[Structure and function of selected Ca(2+) transport systems in cardiac cells]

Transport systems, which transfer calcium across the plasma membrane or from the intracellular stores belong to important modulators of the intracellular calcium concentration. It is well known that the maintenance of the calcium homeostasis becomes the basis of the proper function of the heart muscle and its impairment leads to the development of the pathophysiological changes which may end in the cell death. Diversity of the calcium transport systems is given not only by their function (transfer of calcium across the plasma membrane in both direction) but also by their location (in the plasma membrane or in membranes of the intracellular stores). This review summarizes the current knowledge about the structure and function of selected calcium systems in the cardiac cells. We focused mainly on the L-type calcium channel, which is involved in the process of excitation and contraction coupling, and on the Na/Ca exchanger, which is considered to be an important system for the calcium extrusion from the heart cells.