Abstract
In the cell membranes, there are specific transporters that promote the pump of the cyclic nucleotides out of the cell. These transporters are also key proteins that control the intracellular levels of these nucleotides. These transporters (also known as multidrug resistance proteins) include the subtypes MRP4 and MRP5, which are encoded by the genes Abcc4 and Abcc5, respectively. Our gro…