Transient state kinetic studies of Ca2+-dependent ATPase and calcium transport by cardiac sarcoplasmic reticulum. Effect of cyclic AMP-dependent protein kinase-catalyzed phosphorylation of phospholamban.

Michihiko Tada; Makoto Yamada; Fumio Ohmori; Takeshi Kuzuya; Makoto Inui; Hiroshi Abe

doi:10.1016/s0021-9258(19)85980-x

March 1, 1980Journal of Biological ChemistryOpen Access

Transient state kinetic studies of Ca2+-dependent ATPase and calcium transport by cardiac sarcoplasmic reticulum. Effect of cyclic AMP-dependent protein kinase-catalyzed phosphorylation of phospholamban.

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Key Points

This study investigates the influence of phospholamban phosphorylation on Ca2+-dependent ATPase activity in cardiac sarcoplasmic reticulum.
Transient kinetic analysis of ATPase dynamics via rapid quenching device after incubation with and without cyclic AMP-dependent protein kinase.
Evaluation of calcium binding and EP formation in Ca2+-free and Ca2+-bound microsomes with varying ATP concentrations.
Comparison of initial rates and maximal EP formation using phosphorylated versus non-phosphorylated preparations.
In Ca2+-free microsomes, phosphorylated ATPase showed enhanced initial rates of EP formation and calcium binding compared to non-phosphorylated.
Significant enhancement of EP formation occurred with greater than 10 µM ATP, while lower ATP concentrations reduced this effect.
Phospholamban phosphorylation notably increases the rate of calcium translocation across the microsomal membrane.

Structured PICO

P

Population

Cardiac microsomes (sarcoplasmic reticulum)

I

Intervention

Incubation with cAMP-dependent protein kinase (phosphorylation of phospholamban)

C

Comparator

Incubation without cAMP-dependent protein kinase

O

Outcome

Transient kinetics of the formation of the phosphorylated intermediate EP of ATPase and calcium bindingsurrogate

Phosphorylation of phospholamban by cAMP-dependent protein kinase accelerates calcium binding and translocation across the cardiac sarcoplasmic reticulum membrane.

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Implication

Accelerates mechanistic insight into SR calcium handling; leaves open translation to human cardiac physiology or therapy.

Abstract

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Cite This Study

Tada et al. (1980) studied this question.

synapsesocial.com/papers/6a24b5d78c55644ebb279b62 https://doi.org/10.1016/s0021-9258(19)85980-x

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Transient state kinetic studies of Ca2+-dependent ATPase and calcium transport by cardiac sarcoplasmic reticulum. Effect of cyclic AMP-dependent protein kinase-catalyzed phosphorylation of phospholamban.

Key Points

Structured PICO

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Transient state kinetic studies of Ca2+-dependent ATPase and calcium transport by cardiac sarcoplasmic reticulum. Effect of cyclic AMP-dependent protein kinase-catalyzed phosphorylation of phospholamban.

Key Points

Structured PICO

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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