There is evidence for the existence of developmental changes in expression of troponin I (TNI) in cardiac thin filaments; however, regulation of TNI expression has not been described. We tested whether thyroid state affects expression of TNI using neonatal and adult rats made hypothyroid by treatment with 6-n-propyl-2-thiouracil. Polyacrylamide gels of myofibrils from hearts of 7-, 14-, 21-, an...

UNLABELLED Antiangiogenic gene transfer inhibiting growth of new blood vessels is a promising approach in cancer therapy. Human troponin I (TnI) efficiently inhibits endothelial cell proliferation, migration, as well as angiogenesis and tumor growth in vivo. However, little is known about its effects on perfusion and tumor biology. METHODS Stable Morris hepatoma (MH3924A) cells overexpressing...

Fourteen monoclonal antibodies (mAbs) against human cardiac troponin I (cTnI) were generated by commonly used experimental techniques. All these antibodies, as well as antibody 414 (HyTest), were specific for human cTnI. Fifteen antibodies thus obtained were tested in a sandwich cTnI immunofluorescence assay (altogether 196 combinations). Ten pairs giving the highest sensitivity were selected f...

Human tumors of various tissue origins show an intriguing over-expression of genes not considered oncogenes, such as that encoding Troponin-I (TnI), a well-known muscle protein. Out of the three TnI genes known in humans, the slow form, TNNI1, is affected the most. Drosophila has only one TnI gene, wupA. Here, we studied excess- and loss-of function of wupA in Drosophila, and assayed TNNI1 down...

BACKGROUND Although global ischemia induces troponin I (TnI) degradation, regional ischemia does not. We hypothesized that this disparity is related to preload-induced proteolysis, which varies as a function of the amount of myocardium at risk of ischemia. METHODS AND RESULTS Isolated rat hearts were buffer-perfused at controlled levels of preload. Increasing preload to 25 mm Hg in the absenc...

The troponin complex, composed of troponin T (TnT), troponin I (TnI), and troponin C (TnC), is the major calcium-dependent regulator of muscle contraction, which is present widely in both vertebrates and invertebrates. Little is known about evolutionary aspects of troponin in the animal kingdom. Using a combination of data mining and functional analysis of TnI, we report evidence that an N-term...

BACKGROUND In hemodialysis patients, elevated plasma troponin concentrations are a common finding that has even increased with the advent of newly developed sensitive assays. However, the interpretation and relevance of this is still under debate. METHODS In this cross-sectional study, we analyzed plasma concentrations of sensitive troponin I (TnI) and troponin T (TnT) in stable ambulatory he...

Protein kinase C (PKC) modulates cardiomyocyte function by phosphorylation of intracellular targets including myofilament proteins. Data generated from studies on in vitro heart preparations indicate that PKC phosphorylation of troponin I (TnI), primarily via PKC-epsilon, may slow the rates of cardiac contraction and relaxation (+dP/dt and -dP/dt). To explore this issue in vivo, we employed tra...

The Troponin-Tropomyosin (Tn-Tm) complex regulates muscle contraction through a series of Ca(2+)-dependent conformational changes that control actin-myosin interactions. Members of this complex in Drosophila include the actin-binding protein Troponin I (TnI), and two Tropomyosins (Tm1 and Tm2), which are thought to form heterodimers. We show here that pre-cellular embryos of TnI, Tm1 and Tm2 mu...

A simple chromatographic procedure using DEAE-Sephadex has been established to isolate the troponin I-troponin C complex from unbound troponin I (TnI) and troponin C (TnC). A 1:1 complex can be formed between bovine cardiac carboxamidomethylated troponin I and rabbit skeletal troponin C. The formation of the complex is calcium dependent. It is stable to DEAE-chromatography in 6 M urea, 3 mM Ca2...