Deletion of the titin N2B region accelerates myofibrillar force development but does not alter relaxation kinetics.

ABSTRACT: Cardiac titin is the main determinant of sarcomere stiffness during diastolic relaxation. To explore whether titin stiffness affects the kinetics of cardiac myofibrillar contraction and relaxation, we used subcellular myofibrils from the left ventricles of homozygous and heterozygous N2B-knockout mice which express truncated cardiac titins lacking the unique elastic N2B region. Compared with myofibrils from wild-type mice, myofibrils from knockout and heterozygous mice exhibit increased passive myofibrillar stiffness. To determine the kinetics of Ca(2+)-induced force development (rate constant kACT), myofibrils from knockout, heterozygous and wild-type mice were stretched to the same sarcomere length (2.3 µm) and rapidly activated with Ca(2+). Additionally, mechanically induced force-redev

SUBMITTER: Elhamine F 

PROVIDER: S-EPMC4150059 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature