scholarly journals Basic Residues in the C-Terminal Region of Troponin T are Critical in Skeletal Muscle Regulation

2020 ◽  
Vol 118 (3) ◽  
pp. 495a
Author(s):  
Alfredo J. Lopez-Davila ◽  
Li Zhu ◽  
Leon Fritz ◽  
Theresia Kraft ◽  
Joseph M. Chalovich
Keyword(s):  
Skeletal Muscle ◽  
Troponin T ◽  
Terminal Region ◽  
Muscle Regulation

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.

scholarly journals Cardiac troponin I, cardiac troponin T, and creatine kinase MB in dialysis patients without ischemic heart disease: evidence of cardiac troponin T expression in skeletal muscle

1997 ◽  
Vol 43 (6) ◽  
pp. 976-982 ◽  
Author(s):  
Mary D McLaurin ◽  
Fred S Apple ◽  
Ellen M Voss ◽  
Charles A Herzog ◽  
Scott W Sharkey
Keyword(s):  
Skeletal Muscle ◽  
Heart Disease ◽  
Ischemic Heart Disease ◽  
Cardiac Troponin ◽  
First Generation ◽  
Troponin T ◽  
Ischemic Heart ◽  
Cardiac Troponin T ◽  
Dialysis Patients ◽  
Acute Ischemic Heart Disease

Abstract Serum cardiac troponin T (cTnT) concentrations are frequently increased in chronic dialysis patients as measured by the first-generation ELISA immunoassay, as is creatine kinase (CK) MB mass in the absence of acute ischemic heart disease. We designed this study to compare four serum markers of myocardial injury [CK-MB mass, first-generation ELISA cTnT, second-generation Enzymun cTnT, and cardiac troponin I (cTnI)] in dialysis patients without acute ischemic heart disease. We also evaluated skeletal muscle from dialysis patients as a potential source of serum cTnT. No patients in the clinical evaluation group (n = 24) studied by history and by physical examination, electrocardiography, and two-dimensional echocardiography had evidence of ischemic heart disease. Biochemical markers were measured in serial predialysis blood samples with specific monoclonal antibody-based immunoassays. For several patients at least one sample measured above the upper reference limit: CK-MB, 7 of 24 (30%); ELISA cTnT, 17 of 24 (71%); Enzymun cTnT, 3 of 18 (17%); and cTnI, 1 of 24 (4%). In a separate group of dialysis patients (n = 5), expression of cTnT, but not cTnI, was demonstrated by Western blot analysis in 4 of 5 skeletal muscle biopsies. Chronic dialysis patients without acute ischemic heart disease frequently had increased serum CK-MB and cTnT. The specificity of the second-generation cTnT (Enzymun) assay was improved over that of the first-generation (ELISA) assay; cTnI was the most specific of the currently available biochemical markers. cTnT, but not cTnI, was expressed in the skeletal muscle of dialysis patients.

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.

Involvement of M-cadherin in terminal differentiation of skeletal muscle cells

1995 ◽  
Vol 108 (9) ◽  
pp. 2973-2981 ◽  
Author(s):  
M. Zeschnigk ◽  
D. Kozian ◽  
C. Kuch ◽  
M. Schmoll ◽  
A. Starzinski-Powitz
Keyword(s):  
Cell Cycle ◽  
Skeletal Muscle ◽  
Cell Adhesion ◽  
Troponin T ◽  
Terminal Differentiation ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Myogenic Cells ◽  
Calcium Dependent ◽  
Tissue Organization

Cadherins are a gene family encoding calcium-dependent cell adhesion proteins which are thought to act in the establishment and maintenance of tissue organization. M-cadherin, one member of the family, has been found in myogenic cells of somitic origin during embryogenesis and in the adult. These findings have suggested that M-cadherin is involved in the regulation of morphogenesis of skeletal muscle cells. Therefore, we investigated the function of M-cadherin in the fusion of myoblasts into myotubes (terminal differentiation) in cell culture. Furthermore, we tested whether M-cadherin might influence (a) the expression of troponin T, a typical marker of biochemical differentiation of skeletal muscle cells, and (b) withdrawal of myoblasts from the cell cycle (called terminal commitment). The studies were performed by using antagonistic peptides which correspond to sequences of the putative M-cadherin binding domain. Analogous peptides of N-cadherin have previously been shown to interfere functionally with the N-cadherin-mediated cell adhesion. In the presence of antagonistic M-cadherin peptides, the fusion of myoblasts into myotubes was inhibited. Analysis of troponin T revealed that it was downregulated at the protein level although its mRNA was still detectable. In addition, withdrawal from the cell cycle typical for terminal commitment of muscle cells was not complete in fusion-blocked myogenic cells. Finally, expression of M-cadherin antisense RNA reducing the expression of the endogenous M-cadherin protein interfered with the fusion process of myoblasts. Our data imply that M-cadherin-mediated myoblast interaction plays an important role in terminal differentiation of skeletal muscle cells.

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