Regulation of sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) in turtle muscle and liver during acute exposure to anoxia

Ramnanan, Christopher J.; McMullen, David C.; Bielecki, A; Storey, Kenneth B.

doi:10.1242/jeb.036087

Cited by 11 publications

(6 citation statements)

References 39 publications

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“…Increased KCl tolerance could mean that the hibernating form of NADP-IDH has increased chemical stability in Richardson's ground squirrels. A similar phenomenon was observed in the SERCA (sarcoendoplasmic reticulum Ca 2+ -ATPase) enzyme of turtles which undergoes anoxia, another form of hypometabolic stress [45].…”

Section: Discussionsupporting

confidence: 66%

Purification and characterization of NADP-isocitrate dehydrogenase from skeletal muscle of Urocitellus richardsonii

2022

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NADP-dependent isocitrate dehydrogenase (NADP-IDH, EC 1.1.1.42) catalyzes the oxidative decarboxylation of isocitrate to α-ketoglutarate with the concomitant production of NADPH. NADPH plays important roles in many biosynthesis pathways, maintenance of proper oxidation-reduction balance, and protection against oxidative damage. This present study investigated the dynamic nature of NADP-IDH during hibernation by purifying it from the skeletal muscle of Richardson's ground squirrel (Urocitellus richardsonii) and analyzing its structural and functional changes in response to hibernation. Kinetic parameters of puri ed NADP-IDH from euthermic and hibernating ground squirrel skeletal muscle were characterized at 22°C and 5°C. Relative to euthermic muscle, NADP-IDH in hibernating muscle had a higher a nity for its substrate, isocitrate at 22°C, whereas at 5°C, there was a signi cant decrease in isocitrate a nity. Western blot analysis revealed greater serine and threonine phosphorylation in hibernator NADP-IDH as compared to euthermic NADP-IDH. In addition, Bioinformatic analysis predicted the presence of 18 threonine and 21 serine phosphorylation sites on squirrel NADP-IDH. The structural and functional changes in NADP-IDH indicate the ability of the organism to reduce energy consumption during hibernation, while emphasizing increased NADPH production, and thus antioxidant activity, during torpor arousal cycles.

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Section: Discussionsupporting

confidence: 66%

Purification and characterization of NADP-isocitrate dehydrogenase from skeletal muscle of Urocitellus richardsonii

2022

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“…Interestingly, however, freeze-tolerant E. solidaginis larvae show a reduction in cellular ATP levels of more than 50% in the frozen, anoxic state (Storey and Storey 1985), so tbis would have the functional effect of reducing SERCA activity as a result of substrate limitation. Phosphorylation of SERCA has also recently been shown to decrease activity in the liver and muscle of an anoxiatolerant turtle (Ramnanan et al 2010). …”

Section: Discussionmentioning

confidence: 99%

In Cold‐Hardy Insects, Seasonal, Temperature, and Reversible Phosphorylation Controls Regulate Sarco/Endoplasmic Reticulum Ca²⁺‐ATPase (SERCA)

McMullen

Ramnanan

Storey

2010

Physiological and Biochemical Zoology

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Winter cold hardiness of insects typically involves one of two major strategies for survival below 0 degrees C: freeze avoidance and freeze tolerance. The two strategies have some common features, including the accumulation of high concentrations of cryoprotectant polyols and the frequent occurrence of diapause. Entry into the hypometabolic state of diapause requires coordinated suppression of major ATP-consuming metabolic processes, and ion motive ATPases are important targets for regulation. This study documents the suppression of sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) activity in the overwintering larvae of two cold-hardy species, the freeze-avoiding gall moth Epiblema scudderiana and the freeze-tolerant gall fly Eurosta solidaginis. Activity was reduced despite a lack of change in SERCA protein levels in E. solidaginis larvae over the winter and a six- to eightfold increase in SERCA protein in E. scudderiana. This implicated posttranslational modification as the mechanism of SERCA suppression, and in vitro incubations indicated that enzyme phosphorylation by protein kinases A, G, or C strongly reduced enzyme activity. A stable reduction in SERCA activity was also seen in cold-acclimated larvae of both species compared with 15 degrees C controls, with significant changes in the kinetic parameters of the E. scudderiana enzyme (e.g., K(m) ATP was 3.2-fold higher in -20 degrees C-acclimated larvae) that were consistent with reduced enzyme function at low temperature. Epiblema scudderiana SERCA was also subject to regulation by differential temperature effects (Arrhenius activation energy increased by approximately threefold below 10 degrees C) and by seasonal changes in the levels of a SERCA inhibitor protein, phospholamban.

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“…SERCA activity measured by the method described previously [31]. SERCA activity was determined from assays in the absence versus presence of 50 nM thapsigargin, a specific inhibitor of SERCA.…”

Section: Methodsmentioning

confidence: 99%

CD38-cADPR-SERCA Signaling Axis Determines Skeletal Muscle Contractile Force in Response to β-Adrenergic Stimulation

Park

Nam

Kim

et al. 2018

Cell Physiol Biochem

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Background/Aims: Cyclic ADP-ribose (cADPR) is a Ca²⁺ -mobilization messenger that acts on ryanodine-sensitive Ca²⁺ channels in the sarcoplasmic reticulum (SR) Ca²⁺ stores. Moreover, it has been proposed that cADPR serves an additional role in activating the sarcoendoplasmic reticulum Ca²⁺ -ATPase (SERCA) pump. The aim of this study was to determine the exact mechanism by which cADPR regulates SR Ca²⁺ stores in physiologically relevant systems. Methods: We analyzed Ca²⁺ signals as well as the production of Ca²⁺ mobilizing messengers in the skeletal muscle cells of mice subjected to intensive exercise or in the SR fractions from skeletal muscle cells after β-adrenergic receptor (β-AR) stimulation. Results: We show that cADPR enhances SERCA activity in skeletal muscle cells in response to β-AR agonists, increasing SR Ca²⁺ uptake. We demonstrate that cADPR is generated by CD38, a cADPR-synthesizing enzyme, increasing muscle Ca²⁺ signals and contractile force during exercise. CD38 is upregulated by the cAMP response element–binding protein (CREB) transcription factor upon β-AR stimuli and exercise. CD38 knockout (KO) mice show defects in their exercise and cADPR synthesis capabilities, lacking a β-AR agonist-induced muscle contraction when compared to wild-type mice. The skeletal muscle of CD38 KO mice exhibits delayed cytosolic Ca²⁺ clearance and reduced SERCA activity upon exercise. Conclusion: These findings provide insight into the physiological adaptive mechanism by which the CD38- cADPR-SERCA signaling axis plays an essential role in muscle contraction under exercise, and define cADPR as an endogenous activator of SERCA in enhancing the SR Ca²⁺ load.

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Regulation of sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) in turtle muscle and liver during acute exposure to anoxia

Cited by 11 publications

References 39 publications

Purification and characterization of NADP-isocitrate dehydrogenase from skeletal muscle of Urocitellus richardsonii

Purification and characterization of NADP-isocitrate dehydrogenase from skeletal muscle of Urocitellus richardsonii

In Cold‐Hardy Insects, Seasonal, Temperature, and Reversible Phosphorylation Controls Regulate Sarco/Endoplasmic Reticulum Ca²⁺‐ATPase (SERCA)

CD38-cADPR-SERCA Signaling Axis Determines Skeletal Muscle Contractile Force in Response to β-Adrenergic Stimulation

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Regulation of sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) in turtle muscle and liver during acute exposure to anoxia

Cited by 11 publications

References 39 publications

Purification and characterization of NADP-isocitrate dehydrogenase from skeletal muscle of Urocitellus richardsonii

Purification and characterization of NADP-isocitrate dehydrogenase from skeletal muscle of Urocitellus richardsonii

In Cold‐Hardy Insects, Seasonal, Temperature, and Reversible Phosphorylation Controls Regulate Sarco/Endoplasmic Reticulum Ca2+‐ATPase (SERCA)

CD38-cADPR-SERCA Signaling Axis Determines Skeletal Muscle Contractile Force in Response to β-Adrenergic Stimulation

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In Cold‐Hardy Insects, Seasonal, Temperature, and Reversible Phosphorylation Controls Regulate Sarco/Endoplasmic Reticulum Ca²⁺‐ATPase (SERCA)