Troponin I is the inhibitory subunit of troponin, the thin filament regulatory complex which confers calcium-sensitivity to striated muscle actomyosin ATPase activity.
Gene References into Functions
Pim-1 is a novel kinase that phosphorylates cTnI primarily at Ser23/24 and Ser150 in cardiomyocytes, which in turn may modulate myofilament function under a variety of physiological and pathophysiological conditions.PMID:29544221
Hyperphosphorylation of this serine199 in cTnI C terminus impacts heart function by depressing diastolic function at baseline and limiting systolic reserve under physiological stresses. Paradoxically, it preserves heart function after ischemia/reperfusion injury, potentially by decreasing proteolysis of cTnI.PMID:28899987
The contributions of cardiac myosin binding protein C and troponin I phosphorylation to beta-adrenergic enhancement of in vivo cardiac functionPMID:26635197
The difference in myosin regulatory light chain phosphorylation between the ventricles of R21C(+/+) in cardiac troponin I mice likely contributes to observed differences in contractile force and the lower tension monitored in the LV of HCM micePMID:25961037
troponin I phosphorylation specifically alters the Ca(2+) sensitivity of isometric tension and the time course of relaxation in cardiac muscle myofibrilsPMID:25418306
Combined troponin I Ser-150 and Ser-23/24 phosphorylation sustains thin filament Ca(2+) sensitivity playing an adaptive role to preserve contraction during acidic ischemia.PMID:24657721
these results indicate that the inability to enhance myofilament relaxation through cTnI phosphorylation predisposes the heart to abnormal diastolic function, reduced accessibility of cardiac reserves, dysautonomia, and hypertrophy.PMID:24973218
Dominant negative TnI-TnT interface mutation decreases the binding affinity of cTnI for TnT, causes early ventricular remodeling, and blunts the beta-adrenergic response of cardiac myocytes.PMID:24898585
R193H and R205H mutation increase the binding affinity of Troponin I for Troponin T and Troponin C.PMID:24326031
Conclude that dilated cardiomyopathy-causing mutations in thin filament proteins abolish the relationship between myofilament Ca(2+) sensitivity and troponin I phosphorylation by PKA.PMID:23539503
The pattern of cTnI post-translational modification depends on sex and hypertrophic cardiomyopathy genotype.PMID:23352598
A new functional and pathological role of amino acid modifications in the N-terminal acidic domain of cardiac TnI has been found that is modified by phosphorylations at TnI(S23/S24).PMID:22940544
Data show that cardiac TnI gene transition and the alternatively spliced cardiac TnT isoform switching occur in postnatal pulmonary vein.PMID:23176202
Conclude that cTnI phosphorylation by AMPK may represent a novel mechanism of regulation of cardiac function.PMID:22456184
Generation and functional characterization of knock-in mice harboring the cardiac troponin I-R21C mutation associated with hypertrophic cardiomyopathy.PMID:22086914
Data suggest that AMPK emerges as a possibly important regulator of cardiac and skeletal contractility via phosphorylation of a preferred site adjacent to the inhibitory loop of the thin filament protein TnI.PMID:21416543
Loss of troponin I leads to myofibril hypersensitivity to Ca(2+) causing impaired relaxation in restrictive cardiomyopathy.PMID:20580639
the functional effect of cTnI mutation and its potential value in compensating for the cTnT abnormalityPMID:20551314
Ca(2+) binding to thin filaments reconstituted with either cTnI(wild-type) or pseudo-phosphorylated cTnI(S23D/S24D), cTnI(T144E), and cTnI(S23D/S24D/T144E) was determined.PMID:20164197
Studies indicate that that immunization of genetically susceptible mice with troponin I but not troponin T induced a robust autoimmune response leading to marked inflammation and fibrosis in the myocardium.PMID:19446498
calcium induces an extended conformation of the inhibitory region of troponin I in cardiac muscle troponinPMID:11724531
regulation of myocyte twitch kinetics by beta-stimulation and by endothelin-1 was altered in myocytes containing mutant cTnIPMID:11934831
PKC-mediated phosphorylation of Ser(43) and Ser(45) of cTnI plays an important role in regulating force development in the intact myocardiumPMID:12003851
Troponin I serines 43/45 and regulation of cardiac myofilament function.PMID:12181153
demonstration of novel site specificity of effects of protein kinase C phosphorylation on function and emphasize the complexity of modulation of the actin-myosin interaction by specific changes in the thin filamentPMID:12551921
the relationship between sarcomere length and myofilament lattice spacing in troponin I transgenic mice was markedly shifted downward to an overall decreased myofilament lattice spacing following protein kinase a treatment.PMID:12562915
A primary role of PKC phosphorylation of cTnI may be to reduce the requirements of the contractile apparatus for both Ca2+ and ATP, thereby promoting efficient ATP utilisation during contraction.PMID:12923217
autoantibodies to cTnI induce heart dysfunction and dilatation by chronic stimulation of Ca2+ influx in cardiomyocytesPMID:14595408
PKC-dependent phosphorylation of TnI has important role in the modulation of cardiac function under basal as well as augmented statesPMID:14726296
cTnI has a pivotal role in the positive inotropic response of the murine heart to beta-adrenergic stimulation.PMID:14966306
protein kinase C phosphorylation of cardiac troponin I plays a dominant role in depressing contractilityPMID:15507454
In conclusion, these data (alpha-chloralose-urethane) demonstrate that alpha-adrenergic-mediated force reduction is mediated through troponin I protein kinase C phosphorylationPMID:15579573
removal of the N-terminal extension of cTnI enhances cardiac function by increasing the rate of myocardial relaxation and lowering left ventricular end diastolic pressure to facilitate ventricular fillingPMID:15611140
The Ca2+ binding properties of various assemblies of the regulatory components that contain one of the cardiomyopathy-related mutant cTnI.PMID:16531415
Abnormal TnI phosphorylation observed in cardiac failure may explain exacerbated relaxation delay in response to increased afterload and contribute to blunted chronotropic reserve.PMID:16936010
The cTnI-G203S mutation disrupts interactions with partner proteins, and results in intracellular Ca2+ dysregulation early in life, suggesting a pathogenic role in development of familial hypertrophic cardiomyopathy.PMID:16950368
TnI deficiency impairs left ventricular relaxation, which leads to diastolic heart failure.PMID:17526646
cTnI-Cre mice have delayed onset of Cre activity during early heart developmentPMID:17540338
The primary effect of protein kinase A phosphorylation of cardiac troponin I is reduced Ca(2+) sensitivity of force, whereas phosphorylation of cardiac myosin-binding protein C accelerates the kinetics of force development.PMID:17641226
Changes in Ca(2+) affinity also support the idea that the equilibrium between states of actin-tropomyosin-troponin was shifted to the inactive state by mutations that mimic troponin I phosphorylation.PMID:17872964
Thr144 in cardiac TnI modulates cardiac myofilament length-dependent activation.PMID:17975107
Lys184 deletion in troponin I impairs relaxation kinetics and induces hypercontractility in murine cardiac myofibrils.PMID:18096573
Simultaneous defects in MHC7 & TnI accelerate onset & progression of familial hypertrophic cardiomyopathy. Compared with single-mutant models, double-mutant mice develop severe disease & premature death, progressing directly to a dilated phenotype.PMID:18362229
Impaired relaxation is the main manifestation in transgenic mice expressing a restrictive cardiomyopathy mutation, R193H, in cardiac TnI.PMID:18408133
Removal of the N-terminal extension of cardiac troponin I as a functional compensation for impaired myocardial beta-adrenergic signalingPMID:18815135
Transfer of troponin I-specific T cells can induce inflammation and fibrosis in wild-type mice, leading to deterioration of contractile function. Two sequence motifs of cTnI that induce inflammation and fibrosis in myocardium are characterized.PMID:18955666
These results indicate that YY1 is a novel regulator of fetal TnI transcription in the heart.PMID:19013134
the nNOS-PMCA4b complex regulates contractility via cAMP and phosphorylation of both PLB and cTnI.PMID:19278978