Troponin I3, cardiac type (TNNI3), also known as cardiac troponin I (cTnI), is the inhibitory element of troponin. It possesses an inhibitory peptide (IP) domain and a switch peptide (SP) domain that is located N-terminal of the IP domain. The gene encoding TNNI3 is localized on human chromosome 19q13.42.
Troponin I3, cardiac type (TNNI3) or cardiac troponin I (cTnI) modulates the diastolic function of the heart. Low expression of TNNI3 is associated with cardiac diastolic dysfunction. Elevated expression of the protein indicates cardiac injury. TNNI3 is a biomarker for myocardial infarction and mutations in the gene encoding it have been linked to hypertrophic cardiomyopathy.
