The Inositol Trisphosphate/Calcium Signaling Pathway in Health and Disease

Many cellular functions are regulated by calcium (Ca(2+)) signals that are generated by different signaling pathways. One of these is the inositol 1,4,5-trisphosphate/calcium (InsP3/Ca(2+)) signaling pathway that operates through either primary or modulatory mechanisms. In its primary role, it generates the Ca(2+) that acts directly to control processes such as metabolism, secretion, fertilization, proliferation, and smooth muscle contraction. Its modulatory role occurs in excitable cells where it modulates the primary Ca(2+) signal generated by the entry of Ca(2+) through voltage-operated channels that releases Ca(2+) from ryanodine receptors (RYRs) on the internal stores. In carrying out this modulatory…