Sarcolipin is a novel regulator of cardiac sarcoplasmic reticulum Ca2+ ATPase 2a (SERCA2a) and is expressed abundantly in atria. In this study we investigated the physiological significance of sarcolipin in the heart by generating a mouse model deficient for sarcolipin. The sarcolipin-null mice do not show any developmental abnormalities or any cardiac pathology. The absence of sarcolipin does not modify the expression level of other Ca2+ handling proteins, in particular phospholamban, and its phosphorylation status. Calcium uptake studies revealed that, in the atria, ablation of sarcolipin resulted in an increase in the affinity of the SERCA pump for Ca2+ and the maximum velocity of Ca2+ uptake rates. An important finding is that ablation of sarcolipin resulted in an increase in atrial Ca2+ transient amplitudes, and this resulted in enhanced atrial contractility. Furthermore, atria from sarcolipin-null mice showed a blunted response to isoproterenol stimulation, implicating sarcolipin as a mediator of beta-adrenergic responses in atria. Our study documented that sarcolipin is a key regulator of SERCA2a in atria. Importantly, our data demonstrate the existence of distinct modulators for the SERCA pump in the atria and ventricles.
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http://dx.doi.org/10.1073/pnas.0707722104 | DOI Listing |
Int J Mol Sci
December 2022
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
Skeletal muscle-based nonshivering thermogenesis (NST) plays an important role in the regulation and maintenance of body temperature in birds and large mammals, which do not contain brown adipose tissue (BAT). However, the relative contribution of muscle-based NST to thermoregulation is not clearly elucidated in wild small mammals, which have evolved an obligate thermogenic organ of BAT. In this study, we investigated whether muscle would become an important site of NST when BAT function is conditionally minimized in Brandt's voles ().
View Article and Find Full Text PDFAm J Physiol Cell Physiol
February 2022
Department of Cell Biology and Molecular Medicine, Rutgers, New Jersey Medical School, Newark, New Jersey.
Duchenne muscular dystrophy (DMD) is an inherited muscle wasting disease. Metabolic impairments and oxidative stress are major secondary mechanisms that severely worsen muscle function in DMD. Here, we sought to determine whether germline reduction or ablation of sarcolipin (SLN), an inhibitor of sarco/endoplasmic reticulum (SR) Ca ATPase (SERCA), improves muscle metabolism and ameliorates muscle pathology in the mouse model of DMD.
View Article and Find Full Text PDFFront Physiol
March 2021
Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, United States.
Sarcolipin (SLN) is a regulator of sarco/endo plasmic reticulum Ca-ATPase (SERCA) pump and has been shown to be involved in muscle nonshivering thermogenesis (NST) and energy metabolism. Interestingly, SLN expression is significantly upregulated both during muscle development and in several disease states. However, the significance of altered SLN expression in muscle patho-physiology is not completely understood.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
January 2021
Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey.
Sarcolipin (SLN) is an inhibitor of sarco/endoplasmic reticulum (SR) Ca-ATPase (SERCA) and expressed at high levels in the ventricles of animal models for and patients with Duchenne muscular dystrophy (DMD). The goal of this study was to determine whether the germline ablation of SLN expression improves cardiac SERCA function and intracellular Ca (Ca) handling and prevents cardiomyopathy in the mouse model of DMD. Wild-type, , SLN-haploinsufficient (), and SLN-deficient () mice were used for this study.
View Article and Find Full Text PDFJ Biol Chem
June 2017
From the Department of Physiology and
SERCA1, the sarco(endo)plasmic reticulum Ca-ATPase of skeletal muscle, is essential for muscle relaxation and maintenance of low resting Ca levels in the myoplasm. We recently reported that small ankyrin 1 (sAnk1) interacts with the sarco(endo)plasmic reticulum Ca-ATPase in skeletal muscle (SERCA1) to inhibit its activity. We also showed that this interaction is mediated at least in part through sAnk1's transmembrane domain in a manner similar to that of sarcolipin (SLN).
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