The interaction of rabbit skeletal muscle troponin-T fragments with troponin-I

1985 ◽  
Vol 63 (3) ◽  
pp. 212-218 ◽  
Author(s):  
Joyce R. Pearlstone ◽  
Lawrence B. Smillie
Keyword(s):  
Skeletal Muscle ◽  
Ionic Strength ◽  
Cyanogen Bromide ◽  
Troponin I ◽  
Polypeptide Chain ◽  
Troponin T ◽  
Gel Filtration ◽  
Equimolar Amount ◽  
Binding Region ◽  
Helical Content

The interactions of troponin-I (Tn-I) with a variety of fragments spanning the length of the troponin-T (Tn-T) polypeptide chain have been reinvestigated at physiological ionic strength by affinity chromatographic, gel filtration, and circular dichroism methodologies. Strong binding was observed with fragment T2 (residues 159–259) mimicking that observed with whole Tn-T and Tn-I. Partial binding was seen with the shorter cyanogen bromide (CB) fragments of Tn-T in the order CB4 (residues 176–230) > CB6 (residues 239–259) or CB5 (residues 152–175). No interaction with Tn-I was observed with fragments (CB2, CB3, T1) encompassing residues 1–158 of Tn-T. Based on the present results and the work of others, the binding region for Tn-I includes residues 159–259 and perhaps extends into the highly helical CB2 region (residues 71–151) of Tn-T. No evidence has been obtained by ourselves or others for the interaction of the CB3 region (1–70) with Tn-I. A significant increase (11.6%) in α-helical content was observed when an equimolar amount of fragment T2 (residues 159–259) was mixed with Tn-I, a result similar to that seen with whole Tn-T and Tn-I.

The binding sites of rabbit skeletal troponin-I on troponin-T

1980 ◽  
Vol 58 (8) ◽  
pp. 649-654 ◽  
Author(s):  
Joyce R. Pearlstone ◽  
Lawrence B. Smillie
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Binding Site ◽  
Binding Sites ◽  
Troponin I ◽  
Troponin T ◽  
Gel Filtration ◽  
Troponin C ◽  
Separate Site

Various fragments derived from rabbit skeletal muscle troponin-T (Tn-T) by chemical and (or) proteolytic cleavage were mixed with whole troponin-I (Tn-I) and applied to a Sephadex G-75 gel filtration column in order to determine the binding site of Tn-I on Tn-T. This site of interaction was found to span two distinct regions of Tn-T. The first site involves the highly acidic NH2-terminal fragment CB3 (residues 1–70 of Tn-T). A second separate site is located in the region of residues 152–209 of Tn-T. The present study, in conjunction with our earlier work on tropomyosin – Tn-T binding and Tn-T – troponin-C binding, depicts Tn-T as being a functionally efficient molecule composed of several distinct domains of specialized amino acid sequence, each of which carries out a role in the binding of a different protein.

scholarly journals The components of troponin from chicken fast skeletal muscle. A comparison of troponin T and troponin I from breast and leg muscle

1978 ◽  
Vol 169 (1) ◽  
pp. 229-238 ◽  
Author(s):  
J M Wilkinson
Keyword(s):  
Skeletal Muscle ◽  
Troponin I ◽  
Peptide Mapping ◽  
Troponin T ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Chicken Breast ◽  
Fast Skeletal Muscle ◽  
Molecular Weights ◽  
Leg Muscle

The three components of troponin were prepared from chicken breast and leg muscle. The troponin I and T components were separated by chromatography on DEAE-cellulose after citraconylation and without the use of urea-containing buffers. The troponin I and C components were similar to their counterparts from rabbit fast skeletal muscle, and a comparison of the troponin I components from breast and leg muscle by amino acid analysis, gel electrophoresis and peptide ‘mapping’ provides strong evidence for the identity of these proteins. The molecular weights of the troponin T components from breast and leg muscle were 33 500 and 30 500 respectively, determined by gel filtration. A comparison of these two proteins by methods similar to those used for the troponin I components suggested that they differed only in the N-terminal region of the sequence, the breast-muscle troponin T having an extra length of polypeptide chain of approx. 24 residues that is rich in histidine and alanine. The N-terminal hexapeptide sequence, however, is the same in both proteins and is (Ser,Asx,Glx)Thr-Glu-Glu. The genetic implications of these findings are considered.

Abstract 366: Engineered Human Cardiac Tissue from Skeletal Muscle Derived Cells and Induced Pluripotent Stem Cell Derived Cardiomyocytes

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Kimimasa Tobita ◽  
Jason S Tchao ◽  
Jong Kim ◽  
Bo Lin ◽  
Johnny Huard ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Stem Cell ◽  
Pluripotent Stem Cell ◽  
Cardiac Tissue ◽  
Troponin I ◽  
Troponin T ◽  
Induced Pluripotent Stem Cell ◽  
Human Cardiac Tissue ◽  
Induced Pluripotent ◽  
Immature Myocardium

We have previously shown that rat skeletal muscle derived stem cells differentiate into an immature cardiomyocyte (CM) phenotype within a 3-dimensional collagen gel engineered cardiac tissue (ECT). Here, we investigated whether human skeletal muscle derived progenitor cells (skMDCs) can differentiate into a CM phenotype within ECT similar to rat skeletal muscle stem cells and compared the human skMDC-ECT properties with ECT from human induced pluripotent stem cell (iPSc) derived CMs. SkMDCs differentiated into a cardiac muscle phenotype within ECT and exhibited spontaneous beating activity as early as culture day 4 and maintained their activity for more than 2 weeks. SkMDC-ECTs stained positive for cardiac specific troponin-T and troponin-I, and were co-localized with fast skeletal muscle myosin heavy chain (sk-fMHC) with a striated muscle pattern similar to fetal myocardium. The iPS-CM-ECTs maintained spontaneous beating activity for more than 2 weeks from ECT construction. iPS-CM stained positive for both cardiac troponin-T and troponin-I, and were also co-localized with sk-fMHC while the striated expression pattern of sk-fMHC was lost similar to post-natal immature myocardium. Connexin-43 protein was expressed in both engineered tissue types, and the expression pattern was similar to immature myocardium. The skMDC-ECT significantly upregulated expression of cardiac-specific genes compared to conventional 2D culture. SkMDC-ECT displayed cardiac muscle like intracellular calcium ion transients. The contractile force measurements demonstrated functional properties of fetal type myocardium in both ECTs. Our results suggest that engineered human cardiac tissue from skeletal muscle progenitor cells mimics developing fetal myocardium while the engineered cardiac tissue from inducible pluripotent stem cell-derived cardiomyocytes mimics post-natal immature myocardium.

P4420Is exercise-induced cardiac troponin release caused by skeletal muscle injury?

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
T Paana ◽  
S Jaakkola ◽  
E Tuunainen ◽  
S Wittfooth ◽  
K Bamberg ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Troponin ◽  
Muscle Injury ◽  
Troponin I ◽  
Troponin T ◽  
Skeletal Muscle Injury ◽  
Coronary Syndrome ◽  
Marathon Race ◽  
Recreational Runners ◽  
Exercise Induced

Abstract Background Cardiac troponins (cTn) are highly sensitive and specific markers for cardiac injury and a key element in the diagnosis of acute coronary syndrome. Strenuous exercise is known to induce increases in cTn, but the causative factors remain ambiguous. It is also equivocal whether exercise induced skeletal muscle injury is associated with cTn elevation. Purpose The aim of this study was to identify independent predictors for the rise in cardiac troponin T (cTnT) and I (cTnI) concentration and to focus on the relationship between skeletal muscle injury measured by skeletal troponin I (skTnI) and cTn elevations after a marathon race in a large group of male recreational runners. Methods A total of 40 recreational runners participating in the marathon in our city were recruited. The study included baseline visit (prerace) and immediate post-race sampling. Results The post-marathon cTnT concentration rose above the reference limit in 38 (95%) participants and the detection limit for cTnI was exceeded in 34 (85%) participants. Similarly, a 10-fold increase in skTnI concentration was observed and elevated post-race values were seen in all participants. There was no significant correlation between the post-race cTnT or cTnT change and post-race skTnI (Spearman's rho = 0.249, p=0.122, rho = 0.285, p=0.074). However, post-race cTnI and change in cTnI were associated with post-race skTnI (rho = 0.404, p=0.01, rho = 0.460, p=0.003) and creatine kinase (r=0.368, p=0.019) concentration. Subjective exertion or self-reported muscle symptoms did not correlate with post-race cTnT, cTnI or skTnI levels. Post-Race cTnT <40 Post-Race cTnT ≥40 p-value n=18 n=22 Age, years 53.3±12.2 44.0±11.9 0.002 Active training, years 12.0 (9.3) 17.0 (15.8) 0.190 Muscle symptoms 7 (38.9) 11 (52.4) 0.523 Creatinine kinase, ug/l 406 (137) 399 (319) 0.163 N-terminal proBNP ng/l 137±168 158±277 0.783 Skeletal Troponin I, ng/ml 28.6 (41) 56.7 (143) 0.199 Figure 1 Conclusions Cardiac troponin became abnormal in almost all runners after marathon race. The exercise-induced rise in cardiac troponin I is related to simultaneous release of skeletal troponin I. The mechanism of this association remains uncertain, but clinicians should be cautious when interpreting post-exercise troponin levels without clinical symptoms and signs of myocardial ischemia.

scholarly journals Full-Size and Partially Truncated Cardiac Troponin Complexes in the Blood of Patients with Acute Myocardial Infarction

2019 ◽  
Vol 65 (7) ◽  
pp. 882-892 ◽  
Author(s):  
Alexandra V Vylegzhanina ◽  
Alexander E Kogan ◽  
Ivan A Katrukha ◽  
Ekaterina V Koshkina ◽  
Anastasia V Bereznikova ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Troponin I ◽  
Troponin T ◽  
Gel Filtration ◽  
Free Form ◽  
Plasma Samples ◽  
Full Size ◽  
Troponin Complex ◽  
Almost All

AbstractBACKGROUNDThe measurement of cardiac isoforms of troponin I (cTnI) and troponin T (cTnT) is widely used for the diagnosis of acute myocardial infarction (AMI). However, there are conflicting data regarding what forms of cTnI and cTnT are present in the blood of AMI patients. We investigated cTnI and cTnT as components of troponin complexes in the blood of AMI patients.METHODSGel filtration techniques, sandwich fluoroimmunoassays, and Western blotting were used.RESULTSPlasma samples from patients with AMI contained the following troponin complexes: (a) a cTnI-cTnT-TnC complex (ITC) composed of full-size cTnT of 37 kDa or its 29-kDa fragment and full-size cTnI of 29 kDa or its 27-kDa fragments; (b) ITC with lower molecular weight (LMW-ITC) in which cTnT was truncated to the 14-kDa C-terminal fragments; and (c) a binary cTnI-cTnC complex composed of truncated cTnI of approximately 14 kDa. During the progression of the disease, the amount of ITC in AMI samples decreased, whereas the amounts of LMW-ITC and short 16- to 20-kDa cTnT central fragments increased. Almost all full-size cTnT and a 29-kDa cTnT fragment in AMI plasma samples were the components of ITC. No free full-size cTnT was found in AMI plasma samples. Only 16- to 27-kDa central fragments of cTnT were present in a free form in patient blood.CONCLUSIONSA ternary troponin complex exists in 2 forms in the blood of patients with AMI: full-size ITC and LMW-ITC. The binary cTnI-cTnC complex and free cTnT fragments are also present in patient blood.

scholarly journals Conformational modulation of slow skeletal muscle troponin T by an NH2-terminal metal-binding extension

2000 ◽  
Vol 279 (4) ◽  
pp. C1067-C1077 ◽  
Author(s):  
Jian-Ping Jin ◽  
Aihua Chen ◽  
Ozgur Ogut ◽  
Qi-Quan Huang
Keyword(s):  
Skeletal Muscle ◽  
Monoclonal Antibody ◽  
Metal Binding ◽  
Metal Ion ◽  
Troponin I ◽  
Troponin T ◽  
Terminal Region ◽  
Sequence Motif ◽  
Fast Skeletal Muscle ◽  
Slow Skeletal Muscle

Troponin T (TnT) is an essential element in the thin filament Ca2+-regulatory system controlling striated muscle contraction. Alternative RNA splicing generates developmental and muscle type-specific TnT isoforms differing in the hypervariable NH2-terminal region. Using avian fast skeletal muscle TnT containing a metal-binding segment, we have demonstrated a role of the NH2-terminal domain in modulating the conformation of TnT (Wang J and Jin JP. Biochemistry 37: 14519–14528, 1998). To further investigate the structure-function relationship of TnT, the present study constructed and characterized a recombinant protein in which the metal-binding peptide present in avian fast skeletal muscle TnT was fused to the NH2 terminus of mouse slow skeletal muscle TnT. Metal ion or monoclonal antibody binding to the NH2-terminal extension induced conformational changes in other domains of the model TnT molecule. This was shown by the altered affinity to a monoclonal antibody against the COOH-terminal region and a polyclonal antiserum recognizing multiple epitopes. Protein binding assays showed that metal binding to the NH2-terminal extension had effects on the interaction of TnT with troponin I, troponin C, and most significantly, tropomyosin. The data indicate that the NH2-terminal Tx [4–7 repeats of a sequence motif His-(Glu/Ala)-Glu-Ala-His] extension confers a specific conformational modulation in the slow skeletal muscle TnT.

Cardiac Troponin I and T Concentrations in Patients with Cocaine-Associated Chest Pain

1996 ◽  
Vol 33 (3) ◽  
pp. 183-186 ◽  
Author(s):  
Mary McLaurin ◽  
Fred S Apple ◽  
Timothy D Henry ◽  
Scott W Sharkey
Keyword(s):  
Skeletal Muscle ◽  
Chest Pain ◽  
Cardiac Troponin ◽  
Muscle Injury ◽  
Troponin I ◽  
Troponin T ◽  
Acute Chest Pain ◽  
Cardiac Troponin I ◽  
Skeletal Muscle Injury ◽  
Rule Out

Patients with cocaine-related chest pain with electrocardiographic (ECG) abnormalities are often admitted to rule out acute myocardial infarction (AMI). Cardiac troponin I and T should be superior to measurement of creatine kinase (CK)—MB for detecting cardiac injury in patients with coexisting skeletal muscle injury. We prospectively evaluated 19 consecutive patients with acute chest pain related to cocaine use who were hospitalized to rule out AMI. The admission ECG was abnormal in 16 of 19 patients. Total CK and CK—MB were elevated during the hospital course in 14 and 3 patients, respectively. Cardiac troponin I and cardiac troponin T levels were within normal limits in all patients demonstrating that recent myocardial injury did not occur. Clinically, no patient had an AMI. Cocaine-induced thoracic skeletal muscle injury or transient cocaine-induced coronary vasospasm should be considered as alternative sources of chest pain in these patients.

Effect of denervation on the content of cardiac troponin-T and cardiac troponin-I in rat skeletal muscle

2007 ◽  
Vol 40 (5-6) ◽  
pp. 423-426 ◽  
Author(s):  
Salim Fredericks ◽  
Hans Degens ◽  
Godfrina McKoy ◽  
Katie Bainbridge ◽  
Paul O. Collinson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Troponin T ◽  
Cardiac Troponin I ◽  
Cardiac Troponin T ◽  
Rat Skeletal Muscle

scholarly journals Troponin Variants as Markers of Skeletal Muscle Health and Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Monica Rasmussen ◽  
Jian-Ping Jin
Keyword(s):  
Skeletal Muscle ◽  
Troponin I ◽  
Striated Muscle ◽  
Troponin T ◽  
Muscle Quality ◽  
Striated Muscles ◽  
Thin Filaments ◽  
Age Related ◽  
Development And Aging ◽  
Regulation Of Muscle Contraction

Ca2+-regulated contractility is a key determinant of the quality of muscles. The sarcomeric myofilament proteins are essential players in the contraction of striated muscles. The troponin complex in the actin thin filaments plays a central role in the Ca2+-regulation of muscle contraction and relaxation. Among the three subunits of troponin, the Ca2+-binding subunit troponin C (TnC) is a member of the calmodulin super family whereas troponin I (TnI, the inhibitory subunit) and troponin T (TnT, the tropomyosin-binding and thin filament anchoring subunit) are striated muscle-specific regulatory proteins. Muscle type-specific isoforms of troponin subunits are expressed in fast and slow twitch fibers and are regulated during development and aging, and in adaptation to exercise or disuse. TnT also evolved with various alternative splice forms as an added capacity of muscle functional diversity. Mutations of troponin subunits cause myopathies. Owing to their physiological and pathological importance, troponin variants can be used as specific markers to define muscle quality. In this focused review, we will explore the use of troponin variants as markers for the fiber contents, developmental and differentiation states, contractile functions, and physiological or pathophysiological adaptations of skeletal muscle. As protein structure defines function, profile of troponin variants illustrates how changes at the myofilament level confer functional qualities at the fiber level. Moreover, understanding of the role of troponin modifications and mutants in determining muscle contractility in age-related decline of muscle function and in myopathies informs an approach to improve human health.

scholarly journals Anti–Cardiac Troponin Autoantibodies Are Specific to the Conformational Epitopes Formed by Cardiac Troponin I and Troponin T in the Ternary Troponin Complex

2017 ◽  
Vol 63 (1) ◽  
pp. 343-350 ◽  
Author(s):  
Alexandra V Vylegzhanina ◽  
Alexander E Kogan ◽  
Ivan A Katrukha ◽  
Olga V Antipova ◽  
Andrey N Kara ◽  
...  
Keyword(s):  
Cardiac Troponin ◽  
Complex I ◽  
Troponin I ◽  
Troponin T ◽  
Early Stage ◽  
Gel Filtration ◽  
Inhibitory Effect ◽  
Cardiac Troponin I ◽  
Blood Samples ◽  
Troponin Complex

Abstract BACKGROUND Autoantibodies to cardiac troponins (TnAAbs) could negatively affect cardiac troponin I (cTnI) measurements by TnAAbs-sensitive immunoassays. We investigated the epitope specificity of TnAAbs and its influence on cTnI immunodetection in patients with acute myocardial infarction (AMI). METHODS The specificity of TnAAbs was studied in immunoassays and gel-filtration experiments. The influence of TnAAbs on endogenous troponin measurements was studied in 35 plasma samples from 15 patients with AMI. RESULTS The inhibitory effect of TnAAbs on the cTnI immunodetection was observed only for the ternary cardiac troponin complex (I–T–C) and not for the binary cardiac troponin complex (I–C) or free cTnI. In the same TnAAbs-containing samples, the immunodetection of cardiac troponin T (cTnT) added in the form of I–T–C (but not free cTnT) was also inhibited in the assays that used monoclonal antibodies (mAbs) specific to the 223–242 epitope. The negative effects of TnAAbs on the measurements of endogenous cTnI in AMI samples were less than on the measurements of isolated I–T–C and decreased with time after the onset of symptoms. Early AMI blood samples might contain a mixture of the I–T–C and I–C complexes with the ratio gradually changing with the progression of the disease in favor of I–C. CONCLUSIONS The investigated TnAAbs are specific to the structural epitopes formed by cTnI and cTnT molecules in the I–T–C complex. AMI blood samples contain a mixture of I–C and I–T–C complexes. The concentrations of total cTnI at the early stage of AMI could be underestimated in approximately 5%–10% of patients if measured by TnAAbs-sensitive immunoassays.

Sign in / Sign up

Export Citation Format

Share Document