Myofilament proteins: From cardiac disorders to proteomic changes

Myofilament proteins of the cardiac sarcomere house the molecular machinery responsible for generating tension and pressure. Release of intracellular Ca(2+) triggers myofilament tension generation and shortening, but the response to Ca(2+) is modulated by changes in key regulatory proteins. We review how these proteomic changes are essential to adaptive physiological regulation of cardiac output and become maladaptive in cardiac disorders. We also review the essentials of proteomic techniques used to study myofilament protein changes, including degradation, isoform expression, phosphorylation and oxidation. Selected proteomic studies illustrate the applications of these approaches.