Myofilament incorporation and contractile function after gene transfer of cardiac troponin I Ser43/45Ala

► Gene transfer of cTnISer43/45Ala is expressed and incorporated into myocyte sarcomeres. ► Myofilament contractile function is altered by cTnISer43/45Ala. ► Functional changes are not due to alterations in Ca2+ transients or phosphorylation. ► The response to the PKC agonist ET is changed by cTnISer43/45Ala.