A troponin T mutation that causes infantile restrictive cardiomyopathy increases Ca2+ sensitivity of force development and impairs the inhibitory properties of troponin.
Dilated and hypertrophic cardiomyopathy mutations in troponin can blunt effects of protein kinase A (PKA) phosphorylation of cardiac troponin I (cTnI), decreasing myofilament Ca2+-sensitivity; however this effect has never been tested for restrictive cardiomyopathy (RCM) mutants.
Here, we present the case of a large family, in which a single TNNI3 mutation caused variable phenotypic expression, ranging from restrictive cardiomyopathy (RCMP) to hypertrophic cardiomyopathy (HCMP) to near-normal phenotype.
In this review, cardiac troponin I, one of the sarcomeric thin filament protein, will be discussed regarding its role in cardiac function, its deficiency-related diastolic dysfunction, and the mutation of this protein-mediated restrictive cardiomyopathy.
In this review, we highlight the use of acute genetic engineering of adult cardiac myocytes through stoichiometric replacement of sarcomeric proteins in these disease states with particular focus on cardiac troponin I. Stoichiometric replacement of disease causing mutations has been instrumental in defining the molecular mechanisms of hypertrophic and restrictive cardiomyopathy in a cellular context.
Mutations in human cardiac troponin I that are associated with restrictive cardiomyopathy affect basal ATPase activity and the calcium sensitivity of force development.
Mutations in human cardiac troponin I that are associated with restrictive cardiomyopathy affect basal ATPase activity and the calcium sensitivity of force development.