Molecular cloning and expression of chicken cardiac troponin C.

Toyota, Naoji; Shimada, Yutaka; Bader, David M.

doi:10.1161/01.res.65.5.1241

Cited by 16 publications

(6 citation statements)

References 30 publications

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“…It is shown by using specific antibodies that cardiac as well as pectoral TnC exist in the pectoralis muscle of the chick embryo (Toyota and Shimada, 1981). Messenger RNA coding cardiac TnC is also shown in this embryonic muscle (Toyota et al, 1989). However, the present results about the sensitivity to CaZf, Sr"+ , and Ba2+ suggest that pectoral TnC is dominantly expressed in the cultured myotubes.…”

Section: Discussioncontrasting

confidence: 62%

Sensitivity of cultured and skinned chick myotube to calcium, strontium, and barium ions examined by recording isometric contractions

Saito¹,

Yoshida²,

Tanaka³

1992

Journal Cellular Physiology

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Sensitivity of cultured chick myotubes to alkaline earth metal ions was investigated by recording contractile isometric tension through a semiconductor transducer. The myotubes were obtained by culturing myoblasts of chick embryo breast muscles, and skinned chemically before physiological experiments. Contractions developed in response to Ca2+ in a bathing medium higher than 3 x 10(-7) M and reached maximum at 1 x 10(-5) M. Sr2+ was less effective than Ca2+; the threshold concentration was 1 x 10(-5) M and the tension reached maximum at 1 x 10(-3) M. Ba2+ was the least effective among the three alkaline earth metal ions; only one fifth of the Ca(2+)-induced maximum tension was attained at 1 x 10(-3) M. The sensitivity was similar to that of the mature pectoral muscle fiber, a fast twitch muscle fiber, rather than that of the anterior latissimus dorsi, a slow tonic muscle fiber. The sensitivity was shown to be dependent on its troponin C by replacing it with troponin C from the mature pectoral or cardiac muscle. This indicates that TnC of a fast-muscle type is expressed in the cultured chick myotube as in the mature pectoral muscle. The contractile apparatus was thus shown to be well developed in the cultured myotube with characteristics similar to the mature fast twitch muscle fiber.

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Section: Discussioncontrasting

confidence: 62%

Sensitivity of cultured and skinned chick myotube to calcium, strontium, and barium ions examined by recording isometric contractions

Saito¹,

Yoshida²,

Tanaka³

1992

Journal Cellular Physiology

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“…The fact that neither TnI nor Tm manifested isoform shifts during overload is consistent with previous reports. 52,53 In contrast, there are reports of reexpression of a fetal TnT isoform in human failure, 33 and we recently demonstrated a modest TnT isoform switch in hypertrophied rabbit hearts. 28 TnT exists as multiple, developmentally regulated isoforms.…”

Section: Significance Of Changes In Contractile Proteinsmentioning

confidence: 65%

Mechanoenergetic Alterations During the Transition From Cardiac Hypertrophy to Failure in Dahl Salt-Sensitive Rats

et al. 1998

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Background-The time course and mechanisms of altered mechanoenergetics and depressed cross-bridge cycling in hypertrophied and failing myocardium are uncertain. Methods and Results-We studied mechanoenergetics in Dahl salt-sensitive (DS) rats fed high-salt diet (HS) for 6 and 12 (HS-12) weeks to produce compensated hypertrophy and failure. The slope of the end-systolic pressure-volume relation (EЈ max ) was similar in HS-6 and low-salt controls (LS-6), but reduced in HS-12 compared with controls (LS-12 ). There were no changes in troponin I or tropomyosin isoforms. However, the proportion of phosphorylated troponin T was reduced in HS-12 versus LS-12 hearts (PϽ.001). Conclusions-In DS rats, the transition to failure is associated with depressed EЈ max and increased efficiency and economy.These findings are linked to myofibrillar ATPase activity and suggest that mechanisms other than isomyosin switching are important determinants of ventricular energetics. A troponin T isoform switch is one potential mechanism.

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“…Details of these clones have been described elsewhere (17)(18)(19). The cardiac nomenclature for the TnC and TnI mutants is specified according to GenBank accession numbers A27204 (20) and AAA16157 (21), respectively. Further cTnI and cTnC mutants were constructed with the Quick-Change site-directed mutagenesis kit (Stratagene) using complementary oligonucleotides containing the desired mutations into the cysteine-less background (obtained by mutating native cysteines to C35S͞C84S for cTnC and C80I͞C97Sfor cTnI).…”

Section: Methodsmentioning

confidence: 99%

Structure of the inhibitory region of troponin by site directed spin labeling electron paramagnetic resonance

Brown

Sale

Hills

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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Site-directed spin labeling EPR (SDSL-EPRtroponin I ͉ spin labels ͉ Fourier transform electron paramagnetic resonance ͉ DEER ͉ dipolar R egulation of striated muscle contraction is associated with Ca 2ϩ -dependent structural transitions in the muscle thin filament, which is composed of the troponin complex, tropomyosin, and actin. Troponin is composed of three components: TnC, which binds Ca 2ϩ ; TnI, which inhibits actomyosin activity; and TnT, which anchors TnC and TnI to tropomyosin. Muscle contraction is initiated by the binding of Ca 2ϩ to the N-lobe regulatory sites of TnC. The N lobe then undergoes a structural transition from a closed to an open form, which then facilitates the release of the inhibitory region of TnI from actin, binding to TnC and stimulation of the actomyosin ATPase. The mechanism of this signaling pathway is still tentative (for review, see ref. 1).Crystal and NMR structures are available for TnC and several complexes of TnC with TnI fragments. The crystal structure of TnC reveals a dumbbell-shaped protein consisting of two globular domains, joined by a 22-residue central ␣-helix (2-4). Each domain contains a hydrophobic cleft and two helix-loop-helix EF-hand metal binding motifs; two high-affinity Ca 2ϩ ͞Mg 2ϩ sites in the C-terminal domain (sites III and IV) and two low-affinity Ca 2ϩ specific sites in the N-terminal domain (sites I and II). In skeletal TnC, sites III and IV are permanently occupied by Mg 2ϩ and facilitate the structural binding of TnC to the contractile apparatus (5). Binding of Ca 2ϩ to sites I and II is the physiological trigger for muscle contraction. In cardiac TnC, binding site I is inactive and Ca 2ϩ binding to site II does not induce as large a structural change as observed in skeletal TnC (6). TnI is capable of inhibiting actomyosin ATPase in the absence of other subunits, but Ca 2ϩ -dependent regulation requires TnC, TnT, and tropomyosin. The inhibitory region (skTnI 96-117) alone can fully inhibit actomyosin ATPase activity (7) possibly by binding either to actin or to TnC in the ''on'' or ''off'' states (8-10). The corresponding residues for the cardiac inhibitory region are 129-150 because of a unique Ϸ32 residue N-terminal extension of cTnI.Structural information for the intact troponin complex is limited to low-resolution neutron diffraction and electron microscopy studies (11-13), though several high-resolution structures of TnC with bound TnI peptides are available. Two computational models have been recently proposed for the binary complex of TnC and TnI (14,15). Both models have TnI and TnC in an antiparallel arrangement with multiple interaction sites between the two subunits. NMR, crystallography, and neutron scattering was used by Tung et al. (15) to develop a computational model of the binary complex in which TnI winds around TnC in either a left-handed manner (model ''L'') or a right-handed manner (model ''R''). In both structures, the inhibitory region of TnI is modeled as a flexible ␤-hairpin in close proximity to the central helix of TnC. ...

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Molecular cloning and expression of chicken cardiac troponin C.

Cited by 16 publications

References 30 publications

Sensitivity of cultured and skinned chick myotube to calcium, strontium, and barium ions examined by recording isometric contractions

Sensitivity of cultured and skinned chick myotube to calcium, strontium, and barium ions examined by recording isometric contractions

Mechanoenergetic Alterations During the Transition From Cardiac Hypertrophy to Failure in Dahl Salt-Sensitive Rats

Structure of the inhibitory region of troponin by site directed spin labeling electron paramagnetic resonance

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