What does this research mean for the field?

A decrease (rightward shift) in Ca2+ sensitivity is not the sole determinant for the dilated cardiomyopathy phenotype, as different disease-causing Troponin T mutations exhibit distinct effects on Ca2+ sensitivity and maximal ATPase activity. Novelty: ClaimNovelty.CONTRADICTORY. Consensus alignment: ConsensusAlignment.CHALLENGES_CONSENSUS.

What question did this study set out to answer?

To evaluate the biochemical and contractile consequences of dilated cardiomyopathy-associated troponin T mutations on calcium sensitivity, force generation, and actomyosin ATPase activity.

October 1, 2003Journal of Biological ChemistryOpen Access

Different Functional Properties of Troponin T Mutants That Cause Dilated Cardiomyopathy

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Why the study?

Do Troponin T mutants (R141W, ΔK210, K273E) alter Ca2+ sensitivity and maximal force compared to wild-type TnT in cardiac fibers?

Population

Porcine cardiac fibers and reconstituted actin-activated myosin ATPase assays

Comparison

Troponin T (TnT) mutants R141W, ΔK210, and K273E vs Human cardiac wild-type TnT (HCWTnT)

Design

Preclinical

Authors

GVGayathri VenkatramanUniversity of California, Davis KHKeita HaradaKyushu University AGAldrin V. GomesHeart Failure / Cardiomyopathy

Discussion

Member takes

Implication

TnT mutants exert divergent Ca2+ sensitivity effects; challenges uniform DCM mechanism but animal data leave clinical relevance open.

Key Points

To evaluate the biochemical and contractile consequences of dilated cardiomyopathy-associated troponin T mutations on calcium sensitivity, force generation, and actomyosin ATPase activity.
Cloned and expressed recombinant human cardiac wild-type troponin T along with DCM-associated mutants (ΔK210 and R141W) and the hypertrophic-to-dilated mutant (K273E).
Measured calcium sensitivity of isometric force and maximal force generation in skinned porcine cardiac muscle fibers reconstituted with human troponin subunits.
Assayed calcium-activated actomyosin ATPase activity and evaluated secondary protein structure using far-ultraviolet circular dichroism spectroscopy.
TnT-ΔK210 induced a significant decrease in calcium sensitivity of force development, reduced maximal force generation, and lowered calcium-activated maximal ATPase activity compared to wild type.
TnT-R141W caused no significant alteration in calcium sensitivity or maximal force generation, although it resulted in a moderate reduction in maximal ATPase activity.
TnT-K273E produced a significant increase in calcium sensitivity while maintaining maximal actomyosin ATPase activity and secondary structural characteristics comparable to wild type.

Structured PICO

Do Troponin T mutants (R141W, ΔK210, K273E) alter Ca2+ sensitivity and maximal force compared to wild-type TnT in cardiac fibers?

Population

Porcine cardiac fibers and reconstituted actin-activated myosin ATPase assays

Intervention

Troponin T (TnT) mutants R141W, ΔK210, and K273E

Comparator

Human cardiac wild-type TnT (HCWTnT)

Outcome

Ca2+ sensitivity of force development, maximal force, and maximal ATPase activitysurrogate

A rightward shift in Ca2+ sensitivity is not the only determinant for the phenotype of dilated cardiomyopathy caused by Troponin T mutations.

Cite This Study

Venkatraman et al. (2003) studied this question.

synapsesocial.com/papers/6a1ed460ce3e167bb87e8205 https://doi.org/10.1074/jbc.m302148200

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Different Functional Properties of Troponin T Mutants That Cause Dilated Cardiomyopathy

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Different Functional Properties of Troponin T Mutants That Cause Dilated Cardiomyopathy

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

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