The enzyme CaM kinase II relaxes the muscle cells
A certain enzyme, the CaM kinase II, keeps the cardiac muscle flexible. By transferring phosphate groups to the giant protein titin, it relaxes the muscle cells. This is reported by researchers led by Prof. Dr. Wolfgang Linke of the Institute of Physiology at the Ruhr Universität in the journal Circulation Research. In failing hearts, which don't pump enough blood around the body, the scientists found an overly active CaM kinase II. "The phosphorylation of titin could be a new starting point for the treatment of heart failure" Prof. Linke speculates.
Titin phosphorylation determines the mechanical tension of the muscle cell
Titin is the largest protein in the human body, and it acts like a spring which tenses or relaxes the muscle cell. The attachment of phosphate groups to specific titin sites - known as phosphorylation - relaxes the cell. It was already known that the calcium/calmodulin-dependent kinase II, CaM kinase II for short, phosphorylates several proteins in heart cells. Whether it also targets the spring protein titin, has now been examined by the researchers in Bochum.
CaM-Kinase II phosphorylates the giant protein titin