1
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Barry C, Rouhana S, Braun JL, Geromella MS, Fajardo VA, Pyle WG. Perimenopause Decreases SERCA2a Activity in the Hearts of a Mouse Model of Ovarian Failure. Biomolecules 2024; 14:675. [PMID: 38927078 PMCID: PMC11201532 DOI: 10.3390/biom14060675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Revised: 06/06/2024] [Accepted: 06/07/2024] [Indexed: 06/28/2024] Open
Abstract
Risk of cardiovascular disease mortality rises in women after menopause. While increased cardiovascular risk is largely attributed to postmenopausal declines in estrogens, the molecular changes in the heart that contribute to risk are poorly understood. Disruptions in intracellular calcium handling develop in ovariectomized mice and have been implicated in cardiac dysfunction. Using a mouse model of menopause in which ovarian failure occurs over 120 days, we sought to determine if perimenopause impacted calcium removal mechanisms in the heart and identify the molecular mechanisms. Mice were injected with 4-vinylcyclohexene diepoxide (VCD) to induce ovarian failure over 120 days, mimicking perimenopause. Hearts were removed at 60 and 120 days after VCD injections, representing the middle and end of perimenopause. SERCA2a function was significantly diminished at the end of perimenopause. Neither SERCA2a nor phospholamban expression changed at either time point, but phospholamban phosphorylation at S16 and T17 was dynamically altered. Intrinsic SERCA inhibitors sarcolipin and myoregulin increased >4-fold at day 60, as did the native activator DWORF. At the end of perimenopause, sarcolipin and myoregulin returned to baseline levels while DWORF was significantly reduced below controls. Sodium-calcium exchanger expression was significantly increased at the end of perimenopause. These results show that the foundation for increased cardiovascular disease mortality develops in the heart during perimenopause and that regulators of calcium handling exhibit significant fluctuations over time. Understanding the temporal development of cardiovascular risk associated with menopause and the underlying mechanisms is critical to developing interventions that mitigate the rise in cardiovascular mortality that arises after menopause.
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Affiliation(s)
- Ciara Barry
- IMPART Team Canada Investigator Network, Dalhousie Medicine, Saint John, NB E2K 5E2, Canada
| | - Sarah Rouhana
- IMPART Team Canada Investigator Network, Dalhousie Medicine, Saint John, NB E2K 5E2, Canada
| | - Jessica L. Braun
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada (V.A.F.)
- Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Mia S. Geromella
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada (V.A.F.)
- Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Val A. Fajardo
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada (V.A.F.)
- Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - W. Glen Pyle
- IMPART Team Canada Investigator Network, Dalhousie Medicine, Saint John, NB E2K 5E2, Canada
- Women’s Health Research Institute at BC Women’s Hospital + Health Centre, Vancouver, BC V6H 2N9, Canada
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2
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Mareedu S, Fefelova N, Galindo CL, Prakash G, Mukai R, Sadoshima J, Xie LH, Babu GJ. Improved mitochondrial function in the hearts of sarcolipin-deficient dystrophin and utrophin double-knockout mice. JCI Insight 2024; 9:e170185. [PMID: 38564291 PMCID: PMC11141945 DOI: 10.1172/jci.insight.170185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 03/21/2024] [Indexed: 04/04/2024] Open
Abstract
Duchenne muscular dystrophy (DMD) is a progressive muscle-wasting disease associated with cardiomyopathy. DMD cardiomyopathy is characterized by abnormal intracellular Ca2+ homeostasis and mitochondrial dysfunction. We used dystrophin and utrophin double-knockout (mdx:utrn-/-) mice in a sarcolipin (SLN) heterozygous-knockout (sln+/-) background to examine the effect of SLN reduction on mitochondrial function in the dystrophic myocardium. Germline reduction of SLN expression in mdx:utrn-/- mice improved cardiac sarco/endoplasmic reticulum (SR) Ca2+ cycling, reduced cardiac fibrosis, and improved cardiac function. At the cellular level, reducing SLN expression prevented mitochondrial Ca2+ overload, reduced mitochondrial membrane potential loss, and improved mitochondrial function. Transmission electron microscopy of myocardial tissues and proteomic analysis of mitochondria-associated membranes showed that reducing SLN expression improved mitochondrial structure and SR-mitochondria interactions in dystrophic cardiomyocytes. These findings indicate that SLN upregulation plays a substantial role in the pathogenesis of cardiomyopathy and that reducing SLN expression has clinical implications in the treatment of DMD cardiomyopathy.
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MESH Headings
- Animals
- Male
- Mice
- Calcium/metabolism
- Cardiomyopathies/metabolism
- Cardiomyopathies/genetics
- Cardiomyopathies/pathology
- Disease Models, Animal
- Dystrophin/genetics
- Dystrophin/metabolism
- Mice, Inbred mdx
- Mice, Knockout
- Mitochondria, Heart/metabolism
- Mitochondria, Heart/ultrastructure
- Mitochondria, Heart/genetics
- Muscle Proteins/metabolism
- Muscle Proteins/genetics
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/pathology
- Myocardium/metabolism
- Myocardium/pathology
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Proteolipids/metabolism
- Proteolipids/genetics
- Utrophin/genetics
- Utrophin/metabolism
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Affiliation(s)
- Satvik Mareedu
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
| | - Nadezhda Fefelova
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
| | - Cristi L. Galindo
- Vascular Medicine Institute and Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Goutham Prakash
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
| | - Risa Mukai
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
| | - Junichi Sadoshima
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
| | - Gopal J. Babu
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
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3
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Keefe JA, Moore OM, Ho KS, Wehrens XHT. Role of Ca 2+ in healthy and pathologic cardiac function: from normal excitation-contraction coupling to mutations that cause inherited arrhythmia. Arch Toxicol 2023; 97:73-92. [PMID: 36214829 PMCID: PMC10122835 DOI: 10.1007/s00204-022-03385-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 09/15/2022] [Indexed: 01/19/2023]
Abstract
Calcium (Ca2+) ions are a key second messenger involved in the rhythmic excitation and contraction of cardiomyocytes throughout the heart. Proper function of Ca2+-handling proteins is required for healthy cardiac function, whereas disruption in any of these can cause cardiac arrhythmias. This comprehensive review provides a broad overview of the roles of Ca2+-handling proteins and their regulators in healthy cardiac function and the mechanisms by which mutations in these proteins contribute to inherited arrhythmias. Major Ca2+ channels and Ca2+-sensitive regulatory proteins involved in cardiac excitation-contraction coupling are discussed, with special emphasis on the function of the RyR2 macromolecular complex. Inherited arrhythmia disorders including catecholaminergic polymorphic ventricular tachycardia, long QT syndrome, Brugada syndrome, short QT syndrome, and arrhythmogenic right-ventricular cardiomyopathy are discussed with particular emphasis on subtypes caused by mutations in Ca2+-handling proteins.
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Affiliation(s)
- Joshua A Keefe
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Oliver M Moore
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kevin S Ho
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA.,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, One Baylor Plaza, BCM335, Houston, TX, 77030, USA. .,Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA. .,Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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4
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Petrick HL, Brownell S, Vachon B, Brunetta HS, Handy RM, van Loon LJC, Murrant CL, Holloway GP. Dietary nitrate increases submaximal SERCA activity and ADP transfer to mitochondria in slow-twitch muscle of female mice. Am J Physiol Endocrinol Metab 2022; 323:E171-E184. [PMID: 35732003 DOI: 10.1152/ajpendo.00371.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rapid oscillations in cytosolic calcium (Ca2+) coordinate muscle contraction, relaxation, and physical movement. Intriguingly, dietary nitrate decreases ATP cost of contraction, increases force production, and increases cytosolic Ca2+, which would seemingly necessitate a greater demand for sarcoplasmic reticulum Ca2+ ATPase (SERCA) to sequester Ca2+ within the sarcoplasmic reticulum (SR) during relaxation. As SERCA is highly regulated, we aimed to determine the effect of 7-day nitrate supplementation (1 mM via drinking water) on SERCA enzymatic properties and the functional interaction between SERCA and mitochondrial oxidative phosphorylation. In soleus, we report that dietary nitrate increased force production across all stimulation frequencies tested, and throughout a 25 min fatigue protocol. Mice supplemented with nitrate also displayed an ∼25% increase in submaximal SERCA activity and SERCA efficiency (P = 0.053) in the soleus. To examine a possible link between ATP consumption and production, we established a methodology coupling SERCA and mitochondria in permeabilized muscle fibers. The premise of this experiment is that the addition of Ca2+ in the presence of ATP generates ADP from SERCA to support mitochondrial respiration. Similar to submaximal SERCA activity, mitochondrial respiration supported by SERCA-derived ADP was increased by ∼20% following nitrate in red gastrocnemius. This effect was fully attenuated by the SERCA inhibitor cyclopiazonic acid and was not attributed to differences in mitochondrial oxidative capacity, ADP sensitivity, protein content, or reactive oxygen species emission. Overall, these findings suggest that improvements in submaximal SERCA kinetics may contribute to the effects of nitrate on force production during fatigue.NEW & NOTEWORTHY We show that nitrate supplementation increased force production during fatigue and increased submaximal SERCA activity. This was also evident regarding the high-energy phosphate transfer from SERCA to mitochondria, as nitrate increased mitochondrial respiration supported by SERCA-derived ADP. Surprisingly, these observations were only apparent in muscle primarily expressing type I (soleus) but not type II fibers (EDL). These findings suggest that alterations in SERCA properties are a possible mechanism in which nitrate increases force during fatiguing contractions.
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Affiliation(s)
- Heather L Petrick
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands
| | - Stuart Brownell
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Bayley Vachon
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Henver S Brunetta
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
- Department of Physiological Sciences, Federal University of Santa Catarina, Santa Catarina, Brazil
| | - Rachel M Handy
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Luc J C van Loon
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands
| | - Coral L Murrant
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Graham P Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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5
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Sarcoplasmic Reticulum Ca2+ Dysregulation in the Pathophysiology of Inherited Arrhythmia: An Update. Biochem Pharmacol 2022; 200:115059. [DOI: 10.1016/j.bcp.2022.115059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/18/2022] [Accepted: 04/19/2022] [Indexed: 11/19/2022]
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6
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Braun JL, Messner HN, Cleverdon REG, Baranowski RW, Hamstra SI, Geromella MS, Stuart JA, Fajardo VA. Heterozygous SOD2 deletion selectively impairs SERCA function in the soleus of female mice. Physiol Rep 2022; 10:e15285. [PMID: 35581738 PMCID: PMC9114654 DOI: 10.14814/phy2.15285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/05/2022] [Accepted: 04/08/2022] [Indexed: 06/15/2023] Open
Abstract
The sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) restores intracellular Ca2+ ([Ca2+ ]i ) to resting levels after muscle contraction, ultimately eliciting relaxation. SERCA pumps are highly susceptible to tyrosine (T)-nitration, impairing their ability to take up Ca2+ resulting in reduced muscle function and increased [Ca2+ ]i and cellular damage. The mitochondrial antioxidant enzyme, superoxide dismutase 2 (SOD2), converts superoxide radicals into less reactive H2 O2 . Heterozygous deletion of SOD2 (Sod2+/- ) in mice increases mitochondrial oxidative stress; however, the consequences of reduced SOD2 expression in skeletal and cardiac muscle, specifically the effect on SERCA pumps, has yet to be investigated. We obtained soleus, extensor digitorum longus (EDL), and left ventricle (LV) muscles from 6 to 7 month-old wild-type (WT) and Sod2+/- female C57BL/6J mice. Ca2+ -dependent SERCA activity assays were performed to assess SERCA function. Western blotting was conducted to examine the protein content of SERCA, phospholamban, and sarcolipin; and immunoprecipitation experiments were done to assess SERCA2a- and SERCA1a-specific T-nitration. Heterozygous SOD2 deletion did not alter SERCA1a or SERCA2a expression in the soleus or LV but reduced SERCA2a in the EDL compared with WT, though this was not statistically significant. Soleus muscles from Sod2+/- mice showed a significant reduction in SERCA's apparent affinity for Ca2+ when compared to WT, corresponding with significantly elevated SERCA2a T-nitration in the soleus. No effect was seen in the EDL or the LV. This is the first study to investigate the effects of SOD2 deficiency on muscle SERCA function and shows that it selectively impairs SERCA function in the soleus.
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Affiliation(s)
- Jessica L. Braun
- Department of KinesiologyBrock UniversitySt. CatharinesOntarioCanada
- Centre for Bone and Muscle HealthBrock UniversitySt. CatharinesOntarioCanada
- Centre for NeuroscienceBrock UniversitySt. CatharinesOntarioCanada
| | - Holt N. Messner
- Department of KinesiologyBrock UniversitySt. CatharinesOntarioCanada
- Centre for Bone and Muscle HealthBrock UniversitySt. CatharinesOntarioCanada
- Department of Biological SciencesBrock UniversitySt. CatharinesOntarioCanada
| | - Riley E. G. Cleverdon
- Department of KinesiologyBrock UniversitySt. CatharinesOntarioCanada
- Centre for Bone and Muscle HealthBrock UniversitySt. CatharinesOntarioCanada
| | - Ryan W. Baranowski
- Department of KinesiologyBrock UniversitySt. CatharinesOntarioCanada
- Centre for Bone and Muscle HealthBrock UniversitySt. CatharinesOntarioCanada
| | - Sophie I. Hamstra
- Department of KinesiologyBrock UniversitySt. CatharinesOntarioCanada
- Centre for Bone and Muscle HealthBrock UniversitySt. CatharinesOntarioCanada
| | - Mia S. Geromella
- Department of KinesiologyBrock UniversitySt. CatharinesOntarioCanada
- Centre for Bone and Muscle HealthBrock UniversitySt. CatharinesOntarioCanada
| | - Jeffrey A. Stuart
- Department of Biological SciencesBrock UniversitySt. CatharinesOntarioCanada
| | - Val A. Fajardo
- Department of KinesiologyBrock UniversitySt. CatharinesOntarioCanada
- Centre for Bone and Muscle HealthBrock UniversitySt. CatharinesOntarioCanada
- Centre for NeuroscienceBrock UniversitySt. CatharinesOntarioCanada
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7
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Chambers PJ, Juracic ES, Fajardo VA, Tupling AR. The role of SERCA and sarcolipin in adaptive muscle remodeling. Am J Physiol Cell Physiol 2022; 322:C382-C394. [PMID: 35044855 DOI: 10.1152/ajpcell.00198.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Sarcolipin (SLN) is a small integral membrane protein that regulates the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pump. When bound to SERCA, SLN reduces the apparent Ca2+ affinity of SERCA and uncouples SERCA Ca2+ transport from its ATP consumption. As such, SLN plays a direct role in altering skeletal muscle relaxation and energy expenditure. Interestingly, the expression of SLN is dynamic during times of muscle adaptation, where large increases in SLN content are found in response to development, atrophy, overload and disease. Several groups have suggested that increases in SLN, especially in dystrophic muscle, are deleterious to muscle function and exacerbate already abhorrent intracellular Ca2+ levels. However, there is also significant evidence to show that increased SLN content is a beneficial adaptive mechanism which protects the SERCA pump and activates Ca2+ signaling and adaptive remodeling during times of cell stress. In this review, we first discuss the role for SLN in healthy muscle during both development and overload, where SLN has been shown to activate Ca2+ signaling to promote mitochondrial biogenesis, fibre type shifts and muscle hypertrophy. Then, with respect to muscle disease, we summarize the discrepancies in the literature as to whether SLN upregulation is adaptive or maladaptive in nature. This review is the first to offer the concept of SLN hormesis in muscle disease, wherein both too much and too little SLN are detrimental to muscle health. Finally, the underlying mechanisms which activate SLN upregulation are discussed, specifically acknowledging a potential positive feedback loop between SLN and Ca2+ signaling molecules.
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Affiliation(s)
- Paige J Chambers
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Emma S Juracic
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Val A Fajardo
- Department Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - A Russell Tupling
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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8
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Zhihao L, Jingyu N, Lan L, Michael S, Rui G, Xiyun B, Xiaozhi L, Guanwei F. SERCA2a: a key protein in the Ca 2+ cycle of the heart failure. Heart Fail Rev 2021; 25:523-535. [PMID: 31701344 DOI: 10.1007/s10741-019-09873-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Calcium ion (Ca2+) cycle plays a crucial role in the contraction and relaxation of cardiomyocytes. The sarcoplasmic reticulum (SR) acts as an organelle for storing Ca2+, which mediated the release and re-uptake of Ca2+ during contraction and relaxation. Disorders of SR function lead to the dysfunction of Ca2+ cycle and myocardial cell function. The sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a (SERCA2a) acts as a subtype of SERCA expressed in the heart, which mediates the contraction of cardiomyocytes and Ca2+ in the cytoplasm to re-enter into the SR. The rate of uptake of Ca2+ by the SR determines the rate of myocardial relaxation. The regulation of SERCA2a activity controls the contractility and relaxation of the heart, affecting cardiac function. The expression and activity of SERCA2a are reduced in failing hearts. Gene therapy by increasing the expression of SERCA2a in the heart has been proven effective. In addition, SERCA2a is regulated by a variety of factors, including transmembrane micropeptides, protein kinases, and post-translational modifications (PTMs). In this review, we discuss the regulatory factors of SERCA2a and provide new insights into future treatments and the direction of heart failure research. In addition, gene therapy for SERCA2a has recently emerged as therapeutic option and hence will be discussed in this review.
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Affiliation(s)
- Liu Zhihao
- Tianjin Laboratory of Translational Research of TCM Prescription and Syndrome, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Number 314 Anshanxi Road, Nankai District, Tianjin, 300193, People's Republic of China.,State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China
| | - Ni Jingyu
- Tianjin Laboratory of Translational Research of TCM Prescription and Syndrome, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Number 314 Anshanxi Road, Nankai District, Tianjin, 300193, People's Republic of China.,State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China
| | - Li Lan
- Tianjin Laboratory of Translational Research of TCM Prescription and Syndrome, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Number 314 Anshanxi Road, Nankai District, Tianjin, 300193, People's Republic of China.,State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China
| | - Sarhene Michael
- Tianjin Laboratory of Translational Research of TCM Prescription and Syndrome, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Number 314 Anshanxi Road, Nankai District, Tianjin, 300193, People's Republic of China.,State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China
| | - Guo Rui
- Tianjin Laboratory of Translational Research of TCM Prescription and Syndrome, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Number 314 Anshanxi Road, Nankai District, Tianjin, 300193, People's Republic of China.,State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China
| | - Bian Xiyun
- Central Laboratory, The Fifth Central Hospital of Tianjin, Tianjin, 300450, People's Republic of China
| | - Liu Xiaozhi
- Central Laboratory, The Fifth Central Hospital of Tianjin, Tianjin, 300450, People's Republic of China
| | - Fan Guanwei
- Tianjin Laboratory of Translational Research of TCM Prescription and Syndrome, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Number 314 Anshanxi Road, Nankai District, Tianjin, 300193, People's Republic of China. .,State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China.
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9
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Barbot T, Beswick V, Montigny C, Quiniou É, Jamin N, Mouawad L. Deciphering the Mechanism of Inhibition of SERCA1a by Sarcolipin Using Molecular Simulations. Front Mol Biosci 2021; 7:606254. [PMID: 33614704 PMCID: PMC7890198 DOI: 10.3389/fmolb.2020.606254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/06/2020] [Indexed: 12/02/2022] Open
Abstract
SERCA1a is an ATPase calcium pump that transports Ca2+ from the cytoplasm to the sarco/endoplasmic reticulum lumen. Sarcolipin (SLN), a transmembrane peptide, regulates the activity of SERCA1a by decreasing its Ca2+ transport rate, but its mechanism of action is still not well-understood. To decipher this mechanism, we have performed normal mode analysis in the all-atom model, with the SERCA1a-SLN complex, or the isolated SERCA1a, embedded in an explicit membrane. The comparison of the results allowed us to provide an explanation at the atomic level for the action of SLN that is in good agreement with experimental observations. In our analyses, the presence of SLN locally perturbs the TM6 transmembrane helix and as a consequence modifies the position of D800, one of the key metal-chelating residues. Additionally, it reduces the flexibility of the gating residues, V304, and E309 in TM4, at the entrance of the Ca2+ binding sites, which would decrease the affinity for Ca2+. Unexpectedly, SLN has also an effect on the ATP binding site more than 35 Å away, due to the straightening of TM5, a long helix considered as the spine of the protein. The straightening of TM5 modifies the structure of the P-N linker that sits above it, and which comprises the 351DKTG354 conserved motif, resulting in an increase of the distance between ATP and the phosphorylation site. As a consequence, the turn-over rate could be affected. All this gives SERCA1a the propensity to go toward a Ca2+ low-affinity E2-like state in the presence of SLN and toward a Ca2+ high-affinity E1-like state in the absence of SLN. In addition to a general mechanism of inhibition of SERCA1a regulatory peptides, this study also provides an insight into the conformational transition between the E2 and E1 states.
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Affiliation(s)
- Thomas Barbot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Veronica Beswick
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France.,Physics Department, Evry-Val-d'Essonne University, Paris-Saclay University, Evry, France
| | - Cédric Montigny
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Éric Quiniou
- CNRS UMR9187 / INSERM U1196, Institut Curie, PSL Research University, Université Paris-Saclay, Orsay, France
| | - Nadège Jamin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Liliane Mouawad
- CNRS UMR9187 / INSERM U1196, Institut Curie, PSL Research University, Université Paris-Saclay, Orsay, France
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10
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Mechanisms underlying pathological Ca 2+ handling in diseases of the heart. Pflugers Arch 2021; 473:331-347. [PMID: 33399957 PMCID: PMC10070045 DOI: 10.1007/s00424-020-02504-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/01/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Cardiomyocyte contraction relies on precisely regulated intracellular Ca2+ signaling through various Ca2+ channels and transporters. In this article, we will review the physiological regulation of Ca2+ handling and its role in maintaining normal cardiac rhythm and contractility. We discuss how inherited variants or acquired defects in Ca2+ channel subunits contribute to the development or progression of diseases of the heart. Moreover, we highlight recent insights into the role of protein phosphatase subunits and striated muscle preferentially expressed protein kinase (SPEG) in atrial fibrillation, heart failure, and cardiomyopathies. Finally, this review summarizes current drug therapies and new advances in genome editing as therapeutic strategies for the cardiac diseases caused by aberrant intracellular Ca2+ signaling.
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11
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Sarcolipin Exhibits Abundant RNA Transcription and Minimal Protein Expression in Horse Gluteal Muscle. Vet Sci 2020; 7:vetsci7040178. [PMID: 33202832 PMCID: PMC7711957 DOI: 10.3390/vetsci7040178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 11/05/2020] [Indexed: 01/02/2023] Open
Abstract
Ca2+ regulation in equine muscle is important for horse performance, yet little is known about this species-specific regulation. We reported recently that horse encode unique gene and protein sequences for the sarcoplasmic reticulum (SR) Ca2+-transporting ATPase (SERCA) and the regulatory subunit sarcolipin (SLN). Here we quantified gene transcription and protein expression of SERCA and its inhibitory peptides in horse gluteus, as compared to commonly-studied rabbit skeletal muscle. RNA sequencing and protein immunoblotting determined that horse gluteus expresses the ATP2A1 gene (SERCA1) as the predominant SR Ca2+-ATPase isoform and the SLN gene as the most-abundant SERCA inhibitory peptide, as also found in rabbit skeletal muscle. Equine muscle expresses an insignificant level of phospholamban (PLN), another key SERCA inhibitory peptide expressed commonly in a variety of mammalian striated muscles. Surprisingly in horse, the RNA transcript ratio of SLN-to-ATP2A1 is an order of magnitude higher than in rabbit, while the corresponding protein expression ratio is an order of magnitude lower than in rabbit. Thus, SLN is not efficiently translated or maintained as a stable protein in horse muscle, suggesting a non-coding role for supra-abundant SLN mRNA. We propose that the lack of SLN and PLN inhibition of SERCA activity in equine muscle is an evolutionary adaptation that potentiates Ca2+ cycling and muscle contractility in a prey species domestically selected for speed.
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12
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Phospholamban and sarcolipin prevent thermal inactivation of sarco(endo)plasmic reticulum Ca2+-ATPases. Biochem J 2020; 477:4281-4294. [PMID: 33111944 DOI: 10.1042/bcj20200346] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 10/15/2020] [Accepted: 10/28/2020] [Indexed: 12/31/2022]
Abstract
Na+-K+-ATPase from mice lacking the γ subunit exhibits decreased thermal stability. Phospholamban (PLN) and sarcolipin (SLN) are small homologous proteins that regulate sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs) with properties similar to the γ subunit, through physical interactions with SERCAs. Here, we tested the hypothesis that PLN and SLN may protect against thermal inactivation of SERCAs. HEK-293 cells were co-transfected with different combinations of cDNAs encoding SERCA2a, PLN, a PLN mutant (N34A) that cannot bind to SERCA2a, and SLN. One-half of the cells were heat stressed at 40°C for 1 h (HS), and one-half were maintained at 37°C (CTL) before harvesting the cells and isolating microsomes. Compared with CTL, maximal SERCA activity was reduced by 25-35% following HS in cells that expressed either SERCA2a alone or SERCA2a and mutant PLN (N34A) whereas no change in maximal SERCA2a activity was observed in cells that co-expressed SERCA2a and either PLN or SLN following HS. Increases in SERCA2a carbonyl group content and nitrotyrosine levels that were detected following HS in cells that expressed SERCA2a alone were prevented in cells co-expressing SERCA2a with PLN or SLN, whereas co-expression of SERCA2a with mutant PLN (N34A) only prevented carbonyl group formation. In other experiments using knock-out mice, we found that thermal inactivation of SERCA was increased in cardiac left ventricle samples from Pln-null mice and in diaphragm samples from Sln-null mice, compared with WT littermates. Our results show that both PLN and SLN form a protective interaction with SERCA pumps during HS, preventing nitrosylation and oxidation of SERCA and thus preserving its maximal activity.
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Wang Z, Zhang J, Ma XF, Chang H, Peng X, Xu SH, Wang HP, Gao YF. A Temporal Examination of Cytoplasmic Ca 2 + Levels, Sarcoplasmic Reticulum Ca 2 + Levels, and Ca 2 + -Handling-Related Proteins in Different Skeletal Muscles of Hibernating Daurian Ground Squirrels. Front Physiol 2020; 11:562080. [PMID: 33192559 PMCID: PMC7609816 DOI: 10.3389/fphys.2020.562080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/30/2020] [Indexed: 12/13/2022] Open
Abstract
To explore the possible mechanism of the sarcoplasmic reticulum (SR) in the maintenance of cytoplasmic calcium (Ca2+) homeostasis, we studied changes in cytoplasmic Ca2+, SR Ca2+, and Ca2+-handling proteins of slow-twitch muscle (soleus, SOL), fast-twitch muscle (extensor digitorum longus, EDL), and mixed muscle (gastrocnemius, GAS) in different stages in hibernating Daurian ground squirrels (Spermophilus dauricus). Results showed that the level of cytoplasmic Ca2+ increased and SR Ca2+ decreased in skeletal muscle fiber during late torpor (LT) and inter-bout arousal (IBA), but both returned to summer active levels when the animals aroused from and re-entered into torpor (early torpor, ET), suggesting that intracellular Ca2+ is dynamic during hibernation. The protein expression of ryanodine receptor1 (RyR1) increased in the LT, IBA, and ET groups, whereas the co-localization of calsequestrin1 (CSQ1) and RyR1 in GAS muscle decreased in the LT and ET groups, which may increase the possibility of RyR1 channel-mediated Ca2+ release. Furthermore, calcium pump (SR Ca2+-ATPase 1, SERCA1) protein expression increased in the LT, IBA, and ET groups, and the signaling pathway-related factors of SERCA activity [i.e., β-adrenergic receptor2 protein expression (in GAS), phosphorylation levels of phospholamban (in GAS), and calmodulin kinase2 (in SOL)] all increased, suggesting that these factors may be involved in the up-regulation of SERCA1 activity in different groups. The increased protein expression of Ca2+-binding proteins CSQ1 and calmodulin (CaM) indicated that intracellular free Ca2+-binding ability also increased in the LT, IBA, ET, and POST groups. In brief, changes in cytoplasmic and SR Ca2+ concentrations, SR RyR1 and SERCA1 protein expression levels, and major RyR1 and SERCA1 signaling pathway-related factors were unexpectedly active in the torpor stage when metabolic functions were highly inhibited.
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Affiliation(s)
- Zhe Wang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, China.,College of Life Sciences, Qufu Normal University, Qufu, China
| | - Jie Zhang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, China
| | - Xiu-Feng Ma
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, China
| | - Hui Chang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, China
| | - Xin Peng
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, China
| | - Shen-Hui Xu
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, China
| | - Hui-Ping Wang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, China
| | - Yun-Fang Gao
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, Ministry of Education, Xi'an, China
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Liu Z, Zhang Y, Qiu C, Zhu H, Pan S, Jia H, Kang H, Guan G, Hui R, Zhu L, Wang J. Diabetes mellitus exacerbates post-myocardial infarction heart failure by reducing sarcolipin promoter methylation. ESC Heart Fail 2020; 7:1935-1948. [PMID: 32525286 PMCID: PMC7373908 DOI: 10.1002/ehf2.12789] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 04/29/2020] [Accepted: 05/07/2020] [Indexed: 12/15/2022] Open
Abstract
Aims Sarcolipin (SLN) is a key regulator of sarcoplasmic reticulum calcium‐ATPase (SERCA)2a, which handles intracellular calcium re‐uptake. This study was aimed to investigate the involvement of SLN in post‐myocardial infarction (MI) heart failure (HF) in diabetes. Methods and results Diabetes/MI rat models were established. Altered SLN expression in diabetic hearts was screened out by microarray. A myocardiotropic viral vector was used to deliver siRNA to silence SLN. DNA methylation was evaluated by bisulfite sequencing. Cardiac functions were evaluated by invasive haemodynamic examinations. The SERCA2a activity, cytoplasmic calcium concentration ([Ca2+]i), calcium spark, and myocyte contraction were detected. Correlation between HF and diabetes was analysed in a cohort consisted of 101 ST‐segment elevated myocardial infarction (STEMI) patients between 2017 and 2019 [53.54 ± 4.64 years old; 61.4% male gender; HbA1c% 6.15 ± 2.00; and left ventricular ejection fraction (LVEF%) 40.64 ± 3.20%]. SLN expression was evaluated in left ventricular tissue sample from six STEMI patients complicated with diabetes and six STEMI patients without diabetes. Expressions of DNA methyltransferase 1a and DNA methyltransferase 3 were reduced in diabetic hearts, leading to down‐regulation of SLN promoter methylation, resulting in increased SLN expression in rats. Impaired heart systolic functions were found in experimental diabetic MI rats, which were attenuated by SLN silencing. SERCA2a activity reduction and [Ca2+]i elevation were attenuated by SLN silencing in diabetic animal hearts and high‐glucose incubated primary myocytes. SLN silencing suppressed calcium sparks and improved contraction and sarcoplasmic reticulum calcium re‐uptake in high‐glucose incubated primary myocytes. Expression of SLN was up‐regulated in LV sampled from STEMI patients complicated with diabetes compared with non‐diabetic ones (P < 0.05). LVEF% was reduced in STEMI patients complicated with diabetes compared with non‐diabetic ones (P < 0.01). HbA1c% and LVEF% was related (r = −0.218, P = 0.028). Increased HbA1c% was correlated with reduced LVEF% after adjustment for age, sex, body mass index, cigarette smoking, creatinine, UA, low density lipoprotein, K+, Na+, and troponin I (adjusted odds ration = 0.75, 95% confidence interval 0.62–0.90, P = 0.002). Conclusions Diabetes increases the vulnerability of STEMI patients to post‐MI HF by down‐regulating SLN promoter methylation, which further regulates SERCA2a activity via increasing cardiac SLN expression.
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Affiliation(s)
- Zhongwei Liu
- Department of Cardiology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi Province, 710068, China
| | - Yong Zhang
- Department of Cardiology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi Province, 710068, China
| | - Chuan Qiu
- Center for Bioinformatics and Genomics, Department of Global Biostatistics and Data Science, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Haitao Zhu
- Department of Pediatrics, Northwest Women's and Children's Hospital, Xi'an, China
| | - Shuo Pan
- Department of Cardiology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi Province, 710068, China
| | - Hao Jia
- International Medical Services, Affiliated Hospital of Northwest University, Xi'an, China
| | - Hongyan Kang
- Department of Cardiology, Heyang County People's Hospital, Weinan, China
| | - Gongchang Guan
- Department of Cardiology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi Province, 710068, China
| | - Rutai Hui
- Department of Cardiology, Fuwai Hospital, National Center of Cardiovascular Diseases, Beijing, China
| | - Ling Zhu
- Department of Cardiology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi Province, 710068, China
| | - Junkui Wang
- Department of Cardiology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi Province, 710068, China
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15
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Morales Rodriguez B, Domínguez-Rodríguez A, Benitah JP, Lefebvre F, Marais T, Mougenot N, Beauverger P, Bonne G, Briand V, Gómez AM, Muchir A. Activation of sarcolipin expression and altered calcium cycling in LMNA cardiomyopathy. Biochem Biophys Rep 2020; 22:100767. [PMID: 32490213 PMCID: PMC7261707 DOI: 10.1016/j.bbrep.2020.100767] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/12/2020] [Accepted: 04/13/2020] [Indexed: 12/12/2022] Open
Abstract
Cardiomyopathy caused by A-type lamins gene (LMNA) mutations (LMNA cardiomyopathy) is associated with dysfunction of the heart, often leading to heart failure. LMNA cardiomyopathy is highly penetrant with bad prognosis with no specific therapy available. Searching for alternative ways to halt the progression of LMNA cardiomyopathy, we studied the role of calcium homeostasis in the evolution of this disease. We showed that sarcolipin, an inhibitor of the sarco/endoplasmic reticulum (SR) Ca2+ ATPase (SERCA) was abnormally elevated in the ventricular cardiomyocytes of mutated mice compared with wild type mice, leading to an alteration of calcium handling. This occurs early in the progression of the disease, when the left ventricular function was not altered. We further demonstrated that down regulation of sarcolipin using adeno-associated virus (AAV) 9-mediated RNA interference delays cardiac dysfunction in mouse model of LMNA cardiomyopathy. These results showed a novel role for sarcolipin on calcium homeostasis in heart and open perspectives for future therapeutic interventions to LMNA cardiomyopathy. Sarcolipin, an inhibitor of the sarco/endoplasmic reticulum (SR) Ca2+ ATPase (SERCA) was abnormally elevated in the cardiac muscle of a mouse model of cardiomyopathy caused by LMNA mutations. The elevation of sarcolipin expression leads to an alteration of calcium handling. Down regulation of sarcolipin using adeno-associated virus (AAV) 9-mediated RNA interference delays cardiac dysfunction in mouse model of cardiomyopathy caused by LMNA mutations.
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Affiliation(s)
| | - Alejandro Domínguez-Rodríguez
- Inserm, Univ. Paris-Sud, Université Paris-Saclay, UMR-S 1180, “Signaling and Cardiovascular Pathophysiology”, Châtenay-Malabry, France
| | - Jean-Pierre Benitah
- Inserm, Univ. Paris-Sud, Université Paris-Saclay, UMR-S 1180, “Signaling and Cardiovascular Pathophysiology”, Châtenay-Malabry, France
| | - Florence Lefebvre
- Inserm, Univ. Paris-Sud, Université Paris-Saclay, UMR-S 1180, “Signaling and Cardiovascular Pathophysiology”, Châtenay-Malabry, France
| | | | - Nathalie Mougenot
- Sorbonne Université, INSERM, UMS28 Phénotypage du Petit animal, Paris, F-75013, France
| | | | - Gisèle Bonne
- Sorbonne Université, INSERM UMRS974, Paris, France
| | | | - Ana-María Gómez
- Inserm, Univ. Paris-Sud, Université Paris-Saclay, UMR-S 1180, “Signaling and Cardiovascular Pathophysiology”, Châtenay-Malabry, France
| | - Antoine Muchir
- Sorbonne Université, INSERM UMRS974, Paris, France
- Corresponding author.
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16
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Chen J, Sitsel A, Benoy V, Sepúlveda MR, Vangheluwe P. Primary Active Ca 2+ Transport Systems in Health and Disease. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035113. [PMID: 31501194 DOI: 10.1101/cshperspect.a035113] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcium ions (Ca2+) are prominent cell signaling effectors that regulate a wide variety of cellular processes. Among the different players in Ca2+ homeostasis, primary active Ca2+ transporters are responsible for keeping low basal Ca2+ levels in the cytosol while establishing steep Ca2+ gradients across intracellular membranes or the plasma membrane. This review summarizes our current knowledge on the three types of primary active Ca2+-ATPases: the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pumps, the secretory pathway Ca2+- ATPase (SPCA) isoforms, and the plasma membrane Ca2+-ATPase (PMCA) Ca2+-transporters. We first discuss the Ca2+ transport mechanism of SERCA1a, which serves as a reference to describe the Ca2+ transport of other Ca2+ pumps. We further highlight the common and unique features of each isoform and review their structure-function relationship, expression pattern, regulatory mechanisms, and specific physiological roles. Finally, we discuss the increasing genetic and in vivo evidence that links the dysfunction of specific Ca2+-ATPase isoforms to a broad range of human pathologies, and highlight emerging therapeutic strategies that target Ca2+ pumps.
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Affiliation(s)
- Jialin Chen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Aljona Sitsel
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Veronick Benoy
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - M Rosario Sepúlveda
- Department of Cell Biology, Faculty of Sciences, University of Granada, 18071 Granada, Spain
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
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17
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Fajardo VA, Chambers PJ, Juracic ES, Rietze BA, Gamu D, Bellissimo C, Kwon F, Quadrilatero J, Russell Tupling A. Sarcolipin deletion in mdx mice impairs calcineurin signalling and worsens dystrophic pathology. Hum Mol Genet 2019; 27:4094-4102. [PMID: 30137316 DOI: 10.1093/hmg/ddy302] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 08/15/2018] [Indexed: 12/11/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most severe form of muscular dystrophy affecting 1 in 3500 live male births. Although there is no cure for DMD, therapeutic strategies aimed at enhancing calcineurin signalling and promoting the slow fibre phenotype have shown promise in mdx mice, which is the classical mouse model for DMD. Sarcolipin (SLN) is a small protein that regulates the sarco(endo)plasmic reticulum Ca2+-ATPase pump and its expression is highly upregulated in dystrophic skeletal muscle. We have recently shown that SLN in skeletal muscle amplifies calcineurin signalling thereby increasing myofibre size and the slow fibre phenotype. Therefore, in the present study we sought to determine the physiological impact of genetic Sln deletion in mdx mice, particularly on calcineurin signalling, fibre-type distribution and size and dystrophic pathology. We generated an mdx/Sln-null (mdx/SlnKO) mouse colony and hypothesized that the soleus and diaphragm muscles from these mice would display blunted calcineurin signalling, smaller myofibre sizes, an increased proportion of fast fibres and worsened dystrophic pathology compared with mdx mice. Our results show that calcineurin signalling was impaired in mdx/SlnKO mice as indicated by reductions in utrophin, stabilin-2 and calcineurin expression. In addition, mdx/SlnKO muscles contained smaller myofibres, exhibited a slow-to-fast fibre-type switch that corresponded with reduced expression of mitochondrial proteins and displayed a worsened dystrophic pathology compared with mdx muscles. Altogether, our findings demonstrate a critical role for SLN upregulation in dystrophic muscles and suggest that SLN can be viewed as a potential therapeutic target.
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Affiliation(s)
- Val A Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Paige J Chambers
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Emma S Juracic
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Bradley A Rietze
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | | | - Frenk Kwon
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
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18
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Gamu D, Juracic ES, Fajardo VA, Rietze BA, Tran K, Bombardier E, Tupling AR. Phospholamban deficiency does not alter skeletal muscle SERCA pumping efficiency or predispose mice to diet-induced obesity. Am J Physiol Endocrinol Metab 2019; 316:E432-E442. [PMID: 30601702 DOI: 10.1152/ajpendo.00288.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pump is a major contributor to skeletal muscle Ca2+ homeostasis and metabolic rate. SERCA activity can become adaptively uncoupled by its regulator sarcolipin (SLN) to increase the energy demand of Ca2+ pumping, preventing excessive obesity and glucose intolerance in mice. Several other SERCA regulators bear structural and functional resemblance to SLN, including phospholamban (PLN). Here, we sought to examine whether endogenous levels of skeletal muscle PLN control SERCA Ca2+ pumping efficiency and whole body metabolism. Using PLN-null mice ( Pln-/-), we found that soleus (SOL) muscle's SERCA pumping efficiency (measured as an apparent coupling ratio: Ca2+ uptake/ATP hydrolysis) was unaffected by PLN. Expression of Ca2+-handling proteins within the SOL, including SLN, were comparable between Pln-/- and wild-type (WT) littermates, as were fiber-type characteristics. Not surprisingly then, Pln-/- mice developed a similar degree of diet-induced obesity and glucose intolerance as WT controls when given a "Western" high-fat diet. Lack of an excessively obesogenic phenotype of Pln-/- could not be explained by compensation from skeletal muscle SLN or brown adipose tissue uncoupling protein-1 content. In agreement with several other reports, our study lends support to the notion that PLN serves a functionally distinct role from that of SLN in skeletal muscle physiology.
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Affiliation(s)
- Daniel Gamu
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - Emma Sara Juracic
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - Val A Fajardo
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | | | - Khanh Tran
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo , Waterloo, Ontario , Canada
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19
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Komatsu M, Nakada T, Kawagishi H, Kato H, Yamada M. Increase in phospholamban content in mouse skeletal muscle after denervation. J Muscle Res Cell Motil 2019; 39:163-173. [DOI: 10.1007/s10974-019-09504-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/20/2019] [Indexed: 10/27/2022]
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20
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Singh S, Sahoo SK, Periasamy M. Sarcolipin. ENCYCLOPEDIA OF SIGNALING MOLECULES 2018:4832-4836. [DOI: 10.1007/978-3-319-67199-4_101787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
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21
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Partial IGF-1 deficiency is sufficient to reduce heart contractibility, angiotensin II sensibility, and alter gene expression of structural and functional cardiac proteins. PLoS One 2017; 12:e0181760. [PMID: 28806738 PMCID: PMC5555709 DOI: 10.1371/journal.pone.0181760] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/06/2017] [Indexed: 01/15/2023] Open
Abstract
Circulating levels of IGF-1 may decrease under several circumstances like ageing, metabolic syndrome, and advanced cirrhosis. This reduction is associated with insulin resistance, dyslipidemia, progression to type 2 diabetes, and increased risk for cardiovascular diseases. However, underlying mechanisms between IGF-1 deficiency and cardiovascular disease remain elusive. The specific aim of the present work was to study whether the partial IGF-1 deficiency influences heart and/or coronary circulation, comparing vasoactive factors before and after of ischemia-reperfusion (I/R). In addition, histology of the heart was performed together with cardiac gene expression for proteins involved in structure and function (extracellular matrix, contractile proteins, active peptides); carried out using microarrays, followed by RT-qPCR confirmation of the three experimental groups. IGF-1 partial deficiency is associated to a reduction in contractility and angiotensin II sensitivity, interstitial fibrosis as well as altered expression pattern of genes involved in extracellular matrix proteins, calcium dynamics, and cardiac structure and function. Although this work is descriptive, it provides a clear insight of the impact that partial IGF-1 deficiency on the heart and establishes this experimental model as suitable for studying cardiac disease mechanisms and exploring therapeutic options for patients under IGF-1 deficiency conditions.
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22
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Desmond PF, Labuza A, Muriel J, Markwardt ML, Mancini AE, Rizzo MA, Bloch RJ. Interactions between small ankyrin 1 and sarcolipin coordinately regulate activity of the sarco(endo)plasmic reticulum Ca 2+-ATPase (SERCA1). J Biol Chem 2017; 292:10961-10972. [PMID: 28487373 PMCID: PMC5491780 DOI: 10.1074/jbc.m117.783613] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/08/2017] [Indexed: 11/06/2022] Open
Abstract
SERCA1, the sarco(endo)plasmic reticulum Ca2+-ATPase of skeletal muscle, is essential for muscle relaxation and maintenance of low resting Ca2+ levels in the myoplasm. We recently reported that small ankyrin 1 (sAnk1) interacts with the sarco(endo)plasmic reticulum Ca2+-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). Earlier studies have shown that SLN and phospholamban, the other well studied small SERCA-regulatory proteins, oligomerize either alone or together. As sAnk1 is coexpressed with SLN in muscle, we sought to determine whether these two proteins interact with one another when coexpressed exogenously in COS7 cells. Coimmunoprecipitation (coIP) and anisotropy-based FRET (AFRET) assays confirmed this interaction. Our results indicated that sAnk1 and SLN can associate in the sarcoplasmic reticulum membrane and after exogenous expression in COS7 cells in vitro but that their association did not require endogenous SERCA2. Significantly, SLN promoted the interaction between sAnk1 and SERCA1 when the three proteins were coexpressed, and both coIP and AFRET experiments suggested the formation of a complex consisting of all three proteins. Ca2+-ATPase assays showed that sAnk1 ablated SLN's inhibition of SERCA1 activity. These results suggest that sAnk1 interacts with SLN both directly and in complex with SERCA1 and reduces SLN's inhibitory effect on SERCA1 activity.
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Affiliation(s)
- Patrick F Desmond
- From the Department of Physiology and
- Programs in Biochemistry and Molecular Biology
| | - Amanda Labuza
- From the Department of Physiology and
- Neuroscience, and
| | | | | | - Allison E Mancini
- Molecular Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Megan A Rizzo
- From the Department of Physiology and
- Neuroscience, and
- Molecular Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Robert J Bloch
- From the Department of Physiology and
- Programs in Biochemistry and Molecular Biology
- Neuroscience, and
- Molecular Medicine, University of Maryland, Baltimore, Maryland 21201
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Fajardo VA, Gamu D, Mitchell A, Bloemberg D, Bombardier E, Chambers PJ, Bellissimo C, Quadrilatero J, Tupling AR. Sarcolipin deletion exacerbates soleus muscle atrophy and weakness in phospholamban overexpressing mice. PLoS One 2017; 12:e0173708. [PMID: 28278204 PMCID: PMC5344511 DOI: 10.1371/journal.pone.0173708] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 02/24/2017] [Indexed: 11/18/2022] Open
Abstract
Sarcolipin (SLN) and phospholamban (PLN) are two small proteins that regulate the sarco(endo)plasmic reticulum Ca2+-ATPase pumps. In a recent study, we discovered that Pln overexpression (PlnOE) in slow-twitch type I skeletal muscle fibers drastically impaired SERCA function and caused a centronuclear myopathy-like phenotype, severe muscle atrophy and weakness, and an 8 to 9-fold upregulation of SLN protein in the soleus muscles. Here, we sought to determine the physiological role of SLN upregulation, and based on its role as a SERCA inhibitor, we hypothesized that it would represent a maladaptive response that contributes to the SERCA dysfunction and the overall myopathy observed in the PlnOE mice. To this end, we crossed Sln-null (SlnKO) mice with PlnOE mice to generate a PlnOE/SlnKO mouse colony and assessed SERCA function, CNM pathology, in vitro contractility, muscle mass, calcineurin signaling, daily activity and food intake, and proteolytic enzyme activity. Our results indicate that genetic deletion of Sln did not improve SERCA function nor rescue the CNM phenotype, but did result in exacerbated muscle atrophy and weakness, due to a failure to induce type II fiber compensatory hypertrophy and a reduction in total myofiber count. Mechanistically, our findings suggest that impaired calcineurin activation and resultant decreased expression of stabilin-2, and/or impaired autophagic signaling could be involved. Future studies should examine these possibilities. In conclusion, our study demonstrates the importance of SLN upregulation in combating muscle myopathy in the PlnOE mice, and since SLN is upregulated across several myopathies, our findings may reveal SLN as a novel and universal therapeutic target.
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Affiliation(s)
- Val A. Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Andrew Mitchell
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Darin Bloemberg
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Paige J. Chambers
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Catherine Bellissimo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - A. Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
- * E-mail:
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Fajardo VA, Smith IC, Bombardier E, Chambers PJ, Quadrilatero J, Tupling AR. Diaphragm assessment in mice overexpressing phospholamban in slow-twitch type I muscle fibers. Brain Behav 2016; 6:e00470. [PMID: 27134770 PMCID: PMC4842933 DOI: 10.1002/brb3.470] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 03/08/2016] [Accepted: 03/11/2016] [Indexed: 12/30/2022] Open
Abstract
AIMS Phospholamban (PLN) and sarcolipin (SLN) are small inhibitory proteins that regulate the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) pump. Previous work from our laboratory revealed that in the soleus and gluteus minimus muscles of mice overexpressing PLN (Pln (OE)), SERCA function was impaired, dynamin 2 (3-5 fold) and SLN (7-9 fold) were upregulated, and features of human centronuclear myopathy (CNM) were observed. Here, we performed structural and functional experiments to evaluate whether the diaphragm muscles of the Pln (OE) mouse would exhibit CNM pathology and muscle weakness. METHODS Diaphragm muscles from Pln (OE) and WT mice were subjected to histological/histochemical/immunofluorescent staining, Ca(2+)-ATPase and Ca(2+) uptake assays, Western blotting, and in vitro electrical stimulation. RESULTS Our results demonstrate that PLN overexpression reduced SERCA's apparent affinity for Ca(2+) but did not reduce maximal SERCA activity or rates of Ca(2+) uptake. SLN was upregulated 2.5-fold, whereas no changes in dynamin 2 expression were found. With respect to CNM, we did not observe type I fiber predominance, central nuclei, or central aggregation of oxidative activity in diaphragm, although type I fiber hypotrophy was present. Furthermore, in vitro contractility assessment of Pln (OE) diaphragm strips revealed no reductions in force-generating capacity, maximal rates of relaxation or force development, but did indicate that ½ relaxation time was prolonged. CONCLUSIONS Therefore, the effects of PLN overexpression on skeletal muscle phenotype differ between diaphragm and the postural soleus and gluteus minimus muscles. Our findings here point to differences in SLN expression and type I fiber distribution as potential contributing factors.
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Affiliation(s)
| | - Ian Curtis Smith
- Department of Kinesiology University of Waterloo Waterloo ON Canada
| | - Eric Bombardier
- Department of Kinesiology University of Waterloo Waterloo ON Canada
| | - Paige J Chambers
- Department of Kinesiology University of Waterloo Waterloo ON Canada
| | - Joe Quadrilatero
- Department of Kinesiology University of Waterloo Waterloo ON Canada
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Singh S, Sahoo SK, Periasamy M. Sarcolipin. ENCYCLOPEDIA OF SIGNALING MOLECULES 2016:1-5. [DOI: 10.1007/978-1-4614-6438-9_101787-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 08/11/2016] [Indexed: 06/16/2023]
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Shaikh SA, Sahoo SK, Periasamy M. Phospholamban and sarcolipin: Are they functionally redundant or distinct regulators of the Sarco(Endo)Plasmic Reticulum Calcium ATPase? J Mol Cell Cardiol 2015; 91:81-91. [PMID: 26743715 DOI: 10.1016/j.yjmcc.2015.12.030] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/10/2015] [Accepted: 12/29/2015] [Indexed: 10/22/2022]
Abstract
In muscle, the Sarco(Endo)plasmic Reticulum Calcium ATPase (SERCA) activity is regulated by two distinct proteins, PLB and SLN, which are highly conserved throughout vertebrate evolution. PLB is predominantly expressed in the cardiac muscle, while SLN is abundant in skeletal muscle. SLN is also found in the cardiac atria and to a lesser extent in the ventricle. PLB regulation of SERCA is central to cardiac function, both at rest and during extreme physiological demand. Compared to PLB, the physiological relevance of SLN remained a mystery until recently and some even thought it was redundant in function. Studies on SLN suggest that it is an uncoupler of the SERCA pump activity and can increase ATP hydrolysis resulting in heat production. Using genetically engineered mouse models for SLN and PLB, we showed that SLN, not PLB, is required for muscle-based thermogenesis. However, the mechanism of how SLN binding to SERCA results in uncoupling SERCA Ca(2+) transport from its ATPase activity remains unclear. In this review, we discuss recent advances in understanding how PLB and SLN differ in their interaction with SERCA. We will also explore whether structural differences in the cytosolic domain of PLB and SLN are the basis for their unique function and physiological roles in cardiac and skeletal muscle.
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Affiliation(s)
- Sana A Shaikh
- Center for Metabolic Origins of Disease, Cardiovascular Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute, Lake Nona, FL. 6400 Sanger Road, Orlando, FL 32827, United States
| | - Sanjaya K Sahoo
- Center for Metabolic Origins of Disease, Cardiovascular Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute, Lake Nona, FL. 6400 Sanger Road, Orlando, FL 32827, United States
| | - Muthu Periasamy
- Center for Metabolic Origins of Disease, Cardiovascular Metabolism Program, Sanford Burnham Prebys Medical Discovery Institute, Lake Nona, FL. 6400 Sanger Road, Orlando, FL 32827, United States.
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Desmond PF, Muriel J, Markwardt ML, Rizzo MA, Bloch RJ. Identification of Small Ankyrin 1 as a Novel Sarco(endo)plasmic Reticulum Ca2+-ATPase 1 (SERCA1) Regulatory Protein in Skeletal Muscle. J Biol Chem 2015; 290:27854-67. [PMID: 26405035 DOI: 10.1074/jbc.m115.676585] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Indexed: 01/06/2023] Open
Abstract
Small ankyrin 1 (sAnk1) is a 17-kDa transmembrane (TM) protein that binds to the cytoskeletal protein, obscurin, and stabilizes the network sarcoplasmic reticulum in skeletal muscle. We report that sAnk1 shares homology in its TM amino acid sequence with sarcolipin, a small protein inhibitor of the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA). Here we investigate whether sAnk1 and SERCA1 interact. Our results indicate that sAnk1 interacts specifically with SERCA1 in sarcoplasmic reticulum vesicles isolated from rabbit skeletal muscle, and in COS7 cells transfected to express these proteins. This interaction was demonstrated by co-immunoprecipitation and an anisotropy-based FRET method. Binding was reduced ~2-fold by the replacement of all of the TM amino acids of sAnk1 with leucines by mutagenesis. This suggests that, like sarcolipin, sAnk1 interacts with SERCA1 at least in part via its TM domain. Binding of the cytoplasmic domain of sAnk1 to SERCA1 was also detected in vitro. ATPase activity assays show that co-expression of sAnk1 with SERCA1 leads to a reduction of the apparent Ca(2+) affinity of SERCA1 but that the effect of sAnk1 is less than that of sarcolipin. The sAnk1 TM mutant has no effect on SERCA1 activity. Our results suggest that sAnk1 interacts with SERCA1 through its TM and cytoplasmic domains to regulate SERCA1 activity and modulate sequestration of Ca(2+) in the sarcoplasmic reticulum lumen. The identification of sAnk1 as a novel regulator of SERCA1 has significant implications for muscle physiology and the development of therapeutic approaches to treat heart failure and muscular dystrophies linked to Ca(2+) misregulation.
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Affiliation(s)
- Patrick F Desmond
- From the Department of Physiology and Program in Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland 21230
| | | | | | | | - Robert J Bloch
- From the Department of Physiology and Program in Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland 21230
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Fajardo VA, Bombardier E, McMillan E, Tran K, Wadsworth BJ, Gamu D, Hopf A, Vigna C, Smith IC, Bellissimo C, Michel RN, Tarnopolsky MA, Quadrilatero J, Tupling AR. Phospholamban overexpression in mice causes a centronuclear myopathy-like phenotype. Dis Model Mech 2015; 8:999-1009. [PMID: 26035394 PMCID: PMC4527296 DOI: 10.1242/dmm.020859] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/21/2015] [Indexed: 12/16/2022] Open
Abstract
Centronuclear myopathy (CNM) is a congenital myopathy that is histopathologically characterized by centrally located nuclei, central aggregation of oxidative activity, and type I fiber predominance and hypotrophy. Here, we obtained commercially available mice overexpressing phospholamban (PlnOE), a well-known inhibitor of sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs), in their slow-twitch type I skeletal muscle fibers to determine the effects on SERCA function. As expected with a 6- to 7-fold overexpression of phospholamban, SERCA dysfunction was evident in PlnOE muscles, with marked reductions in rates of Ca2+ uptake, maximal ATPase activity and the apparent affinity of SERCA for Ca2+. However, our most significant discovery was that the soleus and gluteus minimus muscles from the PlnOE mice displayed overt signs of myopathy: they histopathologically resembled human CNM, with centrally located nuclei, central aggregation of oxidative activity, type I fiber predominance and hypotrophy, progressive fibrosis and muscle weakness. This phenotype is associated with significant upregulation of muscle sarcolipin and dynamin 2, increased Ca2+-activated proteolysis, oxidative stress and protein nitrosylation. Moreover, in our assessment of muscle biopsies from three human CNM patients, we found a significant 53% reduction in SERCA activity and increases in both total and monomeric PLN content compared with five healthy subjects, thereby justifying future studies with more CNM patients. Altogether, our results suggest that the commercially available PlnOE mouse phenotypically resembles human CNM and could be used as a model to test potential mechanisms and therapeutic strategies. To date, there is no cure for CNM and our results suggest that targeting SERCA function, which has already been shown to be an effective therapeutic target for murine muscular dystrophy and human cardiomyopathy, might represent a novel therapeutic strategy to combat CNM. Summary: Phospholamban overexpression in mouse slow-twitch muscle impairs SERCA function and causes histopathological features associated with human centronuclear myopathy.
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Affiliation(s)
- Val A Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Elliott McMillan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Khanh Tran
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Brennan J Wadsworth
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Andrew Hopf
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Chris Vigna
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Ian C Smith
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Catherine Bellissimo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Robin N Michel
- Department of Exercise Science, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Mark A Tarnopolsky
- Departement of Kinesiology, McMaster University, Hamilton, Ontario L8N 3Z5, Canada Department of Pediatrics, McMaster University, Hamilton, Ontario L8N 3Z5, Canada Department of Medicine, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Shanmugam M, Li D, Gao S, Fefelova N, Shah V, Voit A, Pachon R, Yehia G, Xie LH, Babu GJ. Cardiac specific expression of threonine 5 to alanine mutant sarcolipin results in structural remodeling and diastolic dysfunction. PLoS One 2015; 10:e0115822. [PMID: 25671318 PMCID: PMC4324845 DOI: 10.1371/journal.pone.0115822] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/02/2014] [Indexed: 12/23/2022] Open
Abstract
The functional importance of threonine 5 (T5) in modulating the activity of sarcolipin (SLN), a key regulator of sarco/endoplasmic reticulum (SR) Ca2+ ATPase (SERCA) pump was studied using a transgenic mouse model with cardiac specific expression of threonine 5 to alanine mutant SLN (SLNT5A). In these transgenic mice, the SLNT5A protein replaces the endogenous SLN in atria, while maintaining the total SLN content. The cardiac specific expression of SLNT5A results in severe cardiac structural remodeling accompanied by bi-atrial enlargement. Biochemical analyses reveal a selective downregulation of SR Ca2+ handling proteins and a reduced SR Ca2+ uptake both in atria and in the ventricles. Optical mapping analysis shows slower action potential propagation in the transgenic mice atria. Doppler echocardiography and hemodynamic measurements demonstrate a reduced atrial contractility and an impaired diastolic function. Together, these findings suggest that threonine 5 plays an important role in modulating SLN function in the heart. Furthermore, our studies suggest that alteration in SLN function can cause abnormal Ca2+ handling and subsequent cardiac remodeling and dysfunction.
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Affiliation(s)
- Mayilvahanan Shanmugam
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Dan Li
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Shumin Gao
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Nadezhda Fefelova
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Vikas Shah
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Antanina Voit
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Ronald Pachon
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Ghassan Yehia
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
| | - Gopal J. Babu
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, United States of America
- * E-mail:
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Ca2+-dependent regulations and signaling in skeletal muscle: from electro-mechanical coupling to adaptation. Int J Mol Sci 2015; 16:1066-95. [PMID: 25569087 PMCID: PMC4307291 DOI: 10.3390/ijms16011066] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 12/22/2014] [Indexed: 01/07/2023] Open
Abstract
Calcium (Ca2+) plays a pivotal role in almost all cellular processes and ensures the functionality of an organism. In skeletal muscle fibers, Ca(2+) is critically involved in the innervation of skeletal muscle fibers that results in the exertion of an action potential along the muscle fiber membrane, the prerequisite for skeletal muscle contraction. Furthermore and among others, Ca(2+) regulates also intracellular processes, such as myosin-actin cross bridging, protein synthesis, protein degradation and fiber type shifting by the control of Ca(2+)-sensitive proteases and transcription factors, as well as mitochondrial adaptations, plasticity and respiration. These data highlight the overwhelming significance of Ca(2+) ions for the integrity of skeletal muscle tissue. In this review, we address the major functions of Ca(2+) ions in adult muscle but also highlight recent findings of critical Ca(2+)-dependent mechanisms essential for skeletal muscle-regulation and maintenance.
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Abstract
The endoplasmic reticulum (ER) is a cellular compartment that has a key function in protein translation and folding. Maintaining its integrity is of fundamental importance for organism's physiology and viability. The dynamic regulation of intraluminal ER Ca(2+) concentration directly influences the activity of ER-resident chaperones and stress response pathways that balance protein load and folding capacity. We review the emerging evidence that microRNAs play important roles in adjusting these processes to frequently changing intracellular and environmental conditions to modify ER Ca(2+) handling and storage and maintain ER homeostasis.
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Affiliation(s)
- Fabian Finger
- Institute for Genetics and Cologne Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany.
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Fajardo VA, Bombardier E, Vigna C, Devji T, Bloemberg D, Gamu D, Gramolini AO, Quadrilatero J, Tupling AR. Co-expression of SERCA isoforms, phospholamban and sarcolipin in human skeletal muscle fibers. PLoS One 2013; 8:e84304. [PMID: 24358354 PMCID: PMC3865254 DOI: 10.1371/journal.pone.0084304] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 11/13/2013] [Indexed: 01/22/2023] Open
Abstract
Sarcolipin (SLN) and phospholamban (PLN) inhibit the activity of sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs) by reducing their apparent affinity for Ca2+. A ternary complex between SLN, PLN, and SERCAs results in super-inhibition of SERCA activity. Analysis of skeletal muscle homogenate has limited our current understanding of whether SLN and PLN regulate SERCA1a, SERCA2a, or both in skeletal muscle and whether SLN and PLN are co-expressed in skeletal muscle fibers. Biopsies from human vastus lateralis were analyzed through single fiber Western blotting and immunohisto/fluorescence staining to circumvent this limitation. With a newly generated SLN antibody, we report for the first time that SLN protein is present in human skeletal muscle. Addition of the SLN antibody (50 µg) to vastus lateralis homogenates increased the apparent Ca2+ affinity of SERCA (KCa, pCa units) (-Ab, 5.85 ± 0.02 vs. +Ab, 5.95 ± 0.02) and maximal SERCA activity (μmol/g protein/min) (-Ab, 122 ± 6.4 vs. +Ab, 159 ± 11) demonstrating a functional interaction between SLN and SERCAs in human vastus lateralis. Specifically, our results suggest that although SLN and PLN may preferentially regulate SERCA1a, and SERCA2a, respectively, physiologically they both may regulate either SERCA isoform. Furthermore, we show that SLN and PLN co-immunoprecipitate in human vastus lateralis homogenate and are simultaneously expressed in 81% of the fibers analyzed with Western blotting which implies that super-inhibition of SERCA may exist in human skeletal muscle. Finally, we demonstrate unequivocally that mouse soleus contains PLN protein suggesting that super-inhibition of SERCA may also be important physiologically in rodent skeletal muscle.
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Affiliation(s)
- Val A. Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Chris Vigna
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Tahira Devji
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Darin Bloemberg
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | | | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - A. Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
- * E-mail:
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Sahoo SK, Shaikh SA, Sopariwala DH, Bal NC, Periasamy M. Sarcolipin protein interaction with sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) is distinct from phospholamban protein, and only sarcolipin can promote uncoupling of the SERCA pump. J Biol Chem 2013; 288:6881-9. [PMID: 23341466 DOI: 10.1074/jbc.m112.436915] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Sarco(endo)plasmic reticulum Ca(2+)ATPase (SERCA) pump activity is modulated by phospholamban (PLB) and sarcolipin (SLN) in cardiac and skeletal muscle. Recent data suggest that SLN could play a role in muscle thermogenesis by promoting uncoupling of the SERCA pump (Lee, A.G. (2002) Curr. Opin. Struct. Biol. 12, 547-554 and Bal, N. C., Maurya, S. K., Sopariwala, D. H., Sahoo, S. K., Gupta, S. C., Shaikh, S. A., Pant, M., Rowland, L. A., Bombardier, E., Goonasekera, S. A., Tupling, A. R., Molkentin, J. D., and Periasamy, M. (2012) Nat. Med. 18, 1575-1579), but the mechanistic details are unknown. To better define how binding of SLN to SERCA promotes uncoupling of SERCA, we compared SLN and SERCA1 interaction with that of PLB in detail. The homo-bifunctional cross-linker (1,6-bismaleimidohexane) was employed to detect dynamic protein interaction during the SERCA cycle. Our studies reveal that SLN differs significantly from PLB: 1) SLN primarily affects the Vmax of SERCA-mediated Ca(2+) uptake but not the pump affinity for Ca(2+); 2) SLN can bind to SERCA in the presence of high Ca(2+), but PLB can only interact to the ATP-bound Ca(2+)-free E2 state; and 3) unlike PLB, SLN interacts with SERCA throughout the kinetic cycle and promotes uncoupling of the SERCA pump. Using SERCA transmembrane mutants, we additionally show that PLB and SLN can bind to the same groove but interact with a different set of residues on SERCA. These data collectively suggest that SLN is functionally distinct from PLB; its ability to interact with SERCA in the presence of Ca(2+) causes uncoupling of the SERCA pump and increased heat production.
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Affiliation(s)
- Sanjaya K Sahoo
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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Epp RA, Susser SE, Morissette MP, Kehler DS, Jassal DS, Duhamel TA. Exercise training prevents the development of cardiac dysfunction in the low-dose streptozotocin diabetic rats fed a high-fat diet. Can J Physiol Pharmacol 2012; 91:80-9. [PMID: 23369057 DOI: 10.1139/cjpp-2012-0294] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This study tested the hypothesis that exercise training would prevent the development of diabetes-induced cardiac dysfunction and altered expression of sarcoplasmic reticulum Ca(2 +)-transport proteins in the low-dose streptozotocin-induced diabetic rats fed a high-fat diet (HFD+STZ). Male Sprague-Dawley rats (4 weeks old; 125-150 g) were made diabetic using a high-fat diet (40% fat, w/w) and a low-dose of streptozotocin (35 mg·(kg body mass)(-1)) by intravenous injection. Diabetic animals were divided among a sedentary group (Sed+HFD+STZ) or an exercise-trained group (Ex+HFD+STZ) that accumulated 3554 ± 338 m·day(-1) of voluntary wheel running (mean ± SE). Sedentary animals fed a low-fat diet served as the control (Sed+LFD). Oral glucose tolerance was impaired in the sedentary diabetic group (1179 ± 29; area under the curve (a.u.c.)) compared with that in the sedentary control animals (1447 ± 42 a.u.c.). Although left ventricular systolic function was unchanged by diabetes, impaired E/A ratios (i.e., diastolic function) and rates of pressure decay (-dP/dt) indicated the presence of diastolic dysfunction. Diabetes also reduced SERCA2a protein content and maximal SERCA2a activity (V(max)) by 21% and 32%, respectively. In contrast, the change in each parameter was attenuated by exercise training. Based on these data, it appears that exercise training prevented the development of diabetic cardiomyopathy and the dysregulation of sarcoplasmic reticulum protein content in an inducible animal model of type 2 diabetes.
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Affiliation(s)
- Riley A Epp
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, Faculty of Kinesiology and Recreation Management, 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada
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Summermatter S, Thurnheer R, Santos G, Mosca B, Baum O, Treves S, Hoppeler H, Zorzato F, Handschin C. Remodeling of calcium handling in skeletal muscle through PGC-1α: impact on force, fatigability, and fiber type. Am J Physiol Cell Physiol 2011; 302:C88-99. [PMID: 21918181 DOI: 10.1152/ajpcell.00190.2011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regular endurance exercise remodels skeletal muscle, largely through the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). PGC-1α promotes fiber type switching and resistance to fatigue. Intracellular calcium levels might play a role in both adaptive phenomena, yet a role for PGC-1α in the adaptation of calcium handling in skeletal muscle remains unknown. Using mice with transgenic overexpression of PGC-1α, we now investigated the effect of PGC-1α on calcium handling in skeletal muscle. We demonstrate that PGC-1α induces a quantitative reduction in calcium release from the sarcoplasmic reticulum by diminishing the expression of calcium-releasing molecules. Concomitantly, maximal muscle force is reduced in vivo and ex vivo. In addition, PGC-1α overexpression delays calcium clearance from the myoplasm by interfering with multiple mechanisms involved in calcium removal, leading to higher myoplasmic calcium levels following contraction. During prolonged muscle activity, the delayed calcium clearance might facilitate force production in mice overexpressing PGC-1α. Our results reveal a novel role of PGC-1α in altering the contractile properties of skeletal muscle by modulating calcium handling. Importantly, our findings indicate PGC-1α to be both down- as well as upstream of calcium signaling in this tissue. Overall, our findings suggest that in the adaptation to chronic exercise, PGC-1α reduces maximal force, increases resistance to fatigue, and drives fiber type switching partly through remodeling of calcium transients, in addition to promoting slow-type myofibrillar protein expression and adequate energy supply.
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Affiliation(s)
- Serge Summermatter
- Biozentrum, Department of Pharmacology/Neurobiology, University of Basel, Basel, Switzerland
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Autry JM, Rubin JE, Pietrini SD, Winters DL, Robia SL, Thomas DD. Oligomeric interactions of sarcolipin and the Ca-ATPase. J Biol Chem 2011; 286:31697-706. [PMID: 21737843 DOI: 10.1074/jbc.m111.246843] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have detected directly the interactions of sarcolipin (SLN) and the sarcoplasmic reticulum Ca-ATPase (SERCA) by measuring fluorescence resonance energy transfer (FRET) between fusion proteins labeled with cyan fluorescent protein (donor) and yellow fluorescent protein (acceptor). SLN is a membrane protein that helps control contractility by regulating SERCA activity in fast-twitch and atrial muscle. Here we used FRET microscopy and spectroscopy with baculovirus expression in insect cells to provide direct evidence for: 1) oligomerization of SLN and 2) regulatory complex formation between SLN and the fast-twitch muscle Ca-ATPase (SERCA1a isoform). FRET experiments demonstrated that SLN monomers self-associate into dimers and higher order oligomers in the absence of SERCA, and that SLN monomers also bind to SERCA monomers in a 1:1 binary complex when the two proteins are coexpressed. FRET experiments further demonstrated that the binding affinity of SLN for itself is similar to that for SERCA. Mutating SLN residue isoleucine-17 to alanine (I17A) decreased the binding affinity of SLN self-association and converted higher order oligomers into monomers and dimers. The I17A mutation also decreased SLN binding affinity for SERCA but maintained 1:1 stoichiometry in the regulatory complex. Thus, isoleucine-17 plays dual roles in determining the distribution of SLN homo-oligomers and stabilizing the formation of SERCA-SLN heterodimers. FRET results for SLN self-association were supported by the effects of SLN expression in bacterial cells. We propose that SLN exists as multiple molecular species in muscle, including SERCA-free (monomer, dimer, oligomer) and SERCA-bound (heterodimer), with transmembrane zipper residues of SLN serving to stabilize oligomeric interactions.
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Affiliation(s)
- Joseph M Autry
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Tupling AR, Bombardier E, Gupta SC, Hussain D, Vigna C, Bloemberg D, Quadrilatero J, Trivieri MG, Babu GJ, Backx PH, Periasamy M, MacLennan DH, Gramolini AO. Enhanced Ca2+ transport and muscle relaxation in skeletal muscle from sarcolipin-null mice. Am J Physiol Cell Physiol 2011; 301:C841-9. [PMID: 21697544 DOI: 10.1152/ajpcell.00409.2010] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sarcolipin (SLN) inhibits sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) pumps. To evaluate the physiological significance of SLN in skeletal muscle, we compared muscle contractility and SERCA activity between Sln-null and wild-type mice. SLN protein expression in wild-type mice was abundant in soleus and red gastrocnemius (RG), low in extensor digitorum longus (EDL), and absent from white gastrocnemius (WG). SERCA activity rates were increased in soleus and RG, but not in EDL or WG, from Sln-null muscles, compared with wild type. No differences were seen between wild-type and Sln-null EDL muscles in force-frequency curves or maximum rates of force development (+dF/dt). Maximum relaxation rates (-dF/dt) of EDL were higher in Sln-null than wild type across a range of submaximal stimulation frequencies, but not during a twitch or peak tetanic contraction. For soleus, no differences were seen between wild type and Sln-null in peak tetanic force or +dF/dt; however, force-frequency curves showed that peak force during a twitch and 10-Hz contraction was lower in Sln-null. Changes in the soleus force-frequency curve corresponded with faster rates of force relaxation at nearly all stimulation frequencies in Sln-null compared with wild type. Repeated tetanic stimulation of soleus caused increased (-dF/dt) in wild type, but not in Sln-null. No compensatory responses were detected in analysis of other Ca(2+) regulatory proteins using Western blotting and immunohistochemistry or myosin heavy chain expression using immunofluorescence. These results show that 1) SLN regulates Ca(2+)-ATPase activity thereby regulating contractile kinetics in at least some skeletal muscles, 2) the functional significance of SLN is graded to the endogenous SLN expression level, and 3) SLN inhibitory effects on SERCA function are relieved in response to repeated contractions thus enhancing relaxation rates.
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Abstract
The sarcoplasmic (SERCA 1a) Ca2+-ATPase is a membrane protein abundantly present in skeletal muscles where it functions as an indispensable component of the excitation-contraction coupling, being at the expense of ATP hydrolysis involved in Ca2+/H+ exchange with a high thermodynamic efficiency across the sarcoplasmic reticulum membrane. The transporter serves as a prototype of a whole family of cation transporters, the P-type ATPases, which in addition to Ca2+ transporting proteins count Na+, K+-ATPase and H+, K+-, proton- and heavy metal transporting ATPases as prominent members. The ability in recent years to produce and analyze at atomic (2·3-3 Å) resolution 3D-crystals of Ca2+-transport intermediates of SERCA 1a has meant a breakthrough in our understanding of the structural aspects of the transport mechanism. We describe here the detailed construction of the ATPase in terms of one membraneous and three cytosolic domains held together by a central core that mediates coupling between Ca2+-transport and ATP hydrolysis. During turnover, the pump is present in two different conformational states, E1 and E2, with a preference for the binding of Ca2+ and H+, respectively. We discuss how phosphorylated and non-phosphorylated forms of these conformational states with cytosolic, occluded or luminally exposed cation-binding sites are able to convert the chemical energy derived from ATP hydrolysis into an electrochemical gradient of Ca2+ across the sarcoplasmic reticulum membrane. In conjunction with these basic reactions which serve as a structural framework for the transport function of other P-type ATPases as well, we also review the role of the lipid phase and the regulatory and thermodynamic aspects of the transport mechanism.
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Vandecaetsbeek I, Vangheluwe P, Raeymaekers L, Wuytack F, Vanoevelen J. The Ca2+ pumps of the endoplasmic reticulum and Golgi apparatus. Cold Spring Harb Perspect Biol 2011; 3:cshperspect.a004184. [PMID: 21441596 DOI: 10.1101/cshperspect.a004184] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The various splice variants of the three SERCA- and the two SPCA-pump genes in higher vertebrates encode P-type ATPases of the P(2A) group found respectively in the membranes of the endoplasmic reticulum and the secretory pathway. Of these, SERCA2b and SPCA1a represent the housekeeping isoforms. The SERCA2b form is characterized by a luminal carboxy terminus imposing a higher affinity for cytosolic Ca(2+) compared to the other SERCAs. This is mediated by intramembrane and luminal interactions of this extension with the pump. Other known affinity modulators like phospholamban and sarcolipin decrease the affinity for Ca(2+). The number of proteins reported to interact with SERCA is rapidly growing. Here, we limit the discussion to those for which the interaction site with the ATPase is specified: HAX-1, calumenin, histidine-rich Ca(2+)-binding protein, and indirectly calreticulin, calnexin, and ERp57. The role of the phylogenetically older and structurally simpler SPCAs as transporters of Ca(2+), but also of Mn(2+), is also addressed.
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Affiliation(s)
- Ilse Vandecaetsbeek
- Laboratory of Ca-transport ATPases, Department of Molecular Cell Biology, K.U. Leuven, Leuven, Belgium
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Ng SY, Wong CK, Tsang SY. Differential gene expressions in atrial and ventricular myocytes: insights into the road of applying embryonic stem cell-derived cardiomyocytes for future therapies. Am J Physiol Cell Physiol 2010; 299:C1234-49. [PMID: 20844252 DOI: 10.1152/ajpcell.00402.2009] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myocardial infarction has been the leading cause of morbidity and mortality in developed countries over the past few decades. The transplantation of cardiomyocytes offers a potential method of treatment. However, cardiomyocytes are in high demand and their supply is extremely limited. Embryonic stem cells (ESCs), which have been isolated from the inner cell mass of blastocysts, can self-renew and are pluripotent, meaning they have the ability to develop into any type of cell, including cardiomyocytes. This suggests that ESCs could be a good source of genuine cardiomyocytes for future therapeutic purposes. However, problems with the yield and purity of ESC-derived cardiomyocytes, among other hurdles for the therapeutic application of ESC-derived cardiomyocytes (e.g., potential immunorejection and tumor formation problems), need to be overcome before these cells can be used effectively for cell replacement therapy. ESC-derived cardiomyocytes consist of nodal, atrial, and ventricular cardiomyocytes. Specifically, for treatment of myocardial infarction, transplantation of a sufficient quantity of ventricular cardiomyocytes, rather than nodal or atrial cardiomyocytes, is preferred. Hence, it is important to find ways of increasing the yield and purity of specific types of cardiomyocytes. Atrial and ventricular cardiomyocytes have differential expression of genes (transcription factors, structural proteins, ion channels, etc.) and are functionally distinct. This paper presents a thorough review of differential gene expression in atrial and ventricular myocytes, their expression throughout development, and their regulation. An understanding of the molecular and functional differences between atrial and ventricular myocytes allows discussion of potential strategies for preferentially directing ESCs to differentiate into chamber-specific cells, or for fine tuning the ESC-derived cardiomyocytes into specific electrical and contractile phenotypes resembling chamber-specific cells.
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Affiliation(s)
- Sze Ying Ng
- Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
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Sharma P, Ignatchenko V, Grace K, Ursprung C, Kislinger T, Gramolini AO. Endoplasmic reticulum protein targeting of phospholamban: a common role for an N-terminal di-arginine motif in ER retention? PLoS One 2010; 5:e11496. [PMID: 20634894 PMCID: PMC2901339 DOI: 10.1371/journal.pone.0011496] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 06/16/2010] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Phospholamban (PLN) is an effective inhibitor of the sarco(endo)plasmic reticulum Ca(2+)-ATPase, which transports Ca(2+) into the SR lumen, leading to muscle relaxation. A mutation of PLN in which one of the di-arginine residues at positions 13 and 14 was deleted led to a severe, early onset dilated cardiomyopathy. Here we were interested in determining the cellular mechanisms involved in this disease-causing mutation. METHODOLOGY/PRINCIPAL FINDING Mutations deleting codons for either or both Arg13 or Arg14 resulted in the mislocalization of PLN from the ER. Our data show that PLN is recycled via the retrograde Golgi to ER membrane traffic pathway involving COP-I vesicles, since co-immunoprecipitation assays determined that COP I interactions are dependent on an intact di-arginine motif as PLN RDelta14 did not co-precipitate with COP I containing vesicles. Bioinformatic analysis determined that the di-arginine motif is present in the first 25 residues in a large number of all ER/SR Gene Ontology (GO) annotated proteins. Mutations in the di-arginine motif of the Sigma 1-type opioid receptor, the beta-subunit of the signal recognition particle receptor, and Sterol-O-acyltransferase, three proteins identified in our bioinformatic screen also caused mislocalization of these known ER-resident proteins. CONCLUSION We conclude that PLN is enriched in the ER due to COP I-mediated transport that is dependent on its intact di-arginine motif and that the N-terminal di-arginine motif may act as a general ER retrieval sequence.
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Affiliation(s)
- Parveen Sharma
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Kevin Grace
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Claudia Ursprung
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Thomas Kislinger
- Ontario Cancer Institute, University Health Network, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Anthony O. Gramolini
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Division of Cellular and Molecular Biology, Toronto General Research Institute, Toronto, Ontario, Canada
- * E-mail:
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42
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Wehrens XHT, Ather S, Dobrev D. Role of abnormal sarcoplasmic reticulum function in atrial fibrillation. ACTA ACUST UNITED AC 2010. [DOI: 10.2217/thy.10.8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Vandecaetsbeek I, Raeymaekers L, Wuytack F, Vangheluwe P. Factors controlling the activity of the SERCA2a pump in the normal and failing heart. Biofactors 2009; 35:484-99. [PMID: 19904717 DOI: 10.1002/biof.63] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Heart failure is the leading cause of death in western countries and is often associated with impaired Ca(2+) handling in the cardiomyocyte. In fact, cardiomyocyte relaxation and contraction are tightly controlled by the activity of the cardiac sarco(endo)plasmic reticulum (ER/SR) Ca(2+) pump SERCA2a, pumping Ca(2+) from the cytosol into the lumen of the ER/SR. This review addresses three important facets that control the SERCA2 activity in the heart. First, we focus on the alternative splicing of the SERCA2 messenger, which is strictly regulated in the developing heart. This splicing controls the formation of three SERCA2 splice variants with different enzymatic properties. Second, we will discuss the role and regulation of SERCA2a activity in the normal and failing heart. The two well-studied Ca(2+) affinity modulators phospholamban and sarcolipin control the activity of SERCA2a within a narrow window. An aberrantly high or low Ca(2+) affinity is often observed in and may even trigger cardiac failure. Correcting SERCA2a activity might therefore constitute a therapeutic approach to improve the contractility of the failing heart. Finally, we address the controversies and unanswered questions of other putative regulators of the cardiac Ca(2+) pump, such as sarcalumenin, HRC, S100A1, Bcl-2, HAX-1, calreticulin, calnexin, ERp57, IRS-1, and -2.
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Affiliation(s)
- Ilse Vandecaetsbeek
- Department of Molecular Cell Biology, Laboratory of Ca(2+)-transport ATPases, K.U.Leuven, Leuven, Belgium
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44
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Vangheluwe P, Sepúlveda MR, Missiaen L, Raeymaekers L, Wuytack F, Vanoevelen J. Intracellular Ca2+- and Mn2+-Transport ATPases. Chem Rev 2009; 109:4733-59. [DOI: 10.1021/cr900013m] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Peter Vangheluwe
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - M. Rosario Sepúlveda
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Ludwig Missiaen
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Luc Raeymaekers
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Frank Wuytack
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Jo Vanoevelen
- Laboratory of Ca2+-transport ATPases and Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
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45
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Tupling AR. The decay phase of Ca2+ transients in skeletal muscle: regulation and physiologyThis paper is one of a selection of papers published in this Special Issue, entitled 14th International Biochemistry of Exercise Conference – Muscles as Molecular and Metabolic Machines, and has undergone the Journal’s usual peer review process. Appl Physiol Nutr Metab 2009; 34:373-6. [DOI: 10.1139/h09-033] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cytosolic Ca2+ transients associated with contraction and relaxation cycles in skeletal muscle are primarily dependent on the kinetics of Ca2+ release and Ca2+ uptake by the sarcoplasmic reticulum (SR). In humans, sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs) are solely responsible for the removal of Ca2+ from the cytosol following muscle contraction. There are several signalling systems involved in the acute regulation of SERCAs required to achieve a given Ca2+ transient during muscle contraction–relaxation cycles. Cyclic-AMP-dependent protein kinase and Ca2+/calmodulin-dependent protein kinase signalling activate SERCAs through the regulation of the endogenous SERCA-regulatory proteins, phospholamban and sarcolipin, both of which are highly expressed in human skeletal muscle. Recent studies on the regulation of SERCA2b in arterial smooth muscle and work from my laboratory on the interaction between SERCAs and the inducible 70-kDa heat shock protein suggests a novel role for redox signalling in regulating SERCA activity. In the absence of fatigue, activation of these signalling systems in response to repeated muscle activity serves to increase the rate of cytosolic free Ca2+ ([Ca2+]f) decay (i.e., SR Ca2+ uptake) and the speed of muscle relaxation.
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Affiliation(s)
- A. Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1, Canada (e-mail: )
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46
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Gupta SC, Varian KD, Bal NC, Abraham JL, Periasamy M, Janssen PML. Pulmonary artery banding alters the expression of Ca2+ transport proteins in the right atrium in rabbits. Am J Physiol Heart Circ Physiol 2009; 296:H1933-9. [PMID: 19376811 DOI: 10.1152/ajpheart.00026.2009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Following pulmonary artery banding (PAB), the contractile function of right ventricle diminishes over time. Subsequently, the right atrium (RA) has to contract against a higher afterload, but it is unknown to what extent ventricular dysfunction has an effect on the atrial contractility. We hypothesized that right ventricular pressure overload may have an affect on atrial contractility and Ca(2+) transport protein expression. Therefore, we induced pressure overload of the right ventricle by PAB for 10 wk in rabbits and examined the changes in the expression of Ca(2+) transport proteins in the atrium. We demonstrate that PAB significantly decreased the expression of sarco(endo)plasmic reticulum Ca(2+)-ATPase (Serca) 2a while expression of Na(+)/Ca(2+) exchanger-1 was significantly upregulated in the RA but not in the left atria of rabbit hearts, indicating that pressure is the major trigger. A decrease in Serca2a expression was concomitant with a significant decrease in sarcolipin (SLN), possibly indicating a compensatory role of SLN. The decreased expression of SLN was unable to completely restore sarcoplasmic reticulum Ca(2+) uptake function of Serca2a. Functional contractile assessments in isolated trabeculae showed no difference between PAB- and sham-operated rabbits at 1 Hz but displayed an enhanced force development at higher frequencies and in the presence of isoproterenol, while twitch timing was unaffected. Our results indicate that right ventricular mechanical overload due to PAB affects the expression of the Ca(2+)-handling proteins in the RA in rabbits.
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Affiliation(s)
- Subash C Gupta
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
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Fu MH, Tupling AR. Protective effects of Hsp70 on the structure and function of SERCA2a expressed in HEK-293 cells during heat stress. Am J Physiol Heart Circ Physiol 2009; 296:H1175-83. [PMID: 19252085 DOI: 10.1152/ajpheart.01276.2008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heat shock protein 70 (Hsp70) can physically interact with and prevent thermal inactivation of sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) 1a, the SERCA isoform expressed in adult fast-twitch skeletal muscle. This study examined whether Hsp70 could physically interact with and prevent thermal inactivation of SERCA2a, the SERCA isoform expressed in heart. HEK-293 cells were cotransfected with cDNAs encoding human Hsp70 and rabbit SERCA2a (S2a/Hsp70). Cells cotransfected with SERCA2a cDNA and pMT2 (S2a/pMT2) were used as control. One-half of the cells was heat shocked at 40 degrees C for 1 h (HS), and one-half was maintained at 37 degrees C before harvesting the cells and isolating microsomes. Western blot analysis showed that Hsp70 and SERCA2a were colocalized in the microsomal fraction. The levels of Hsp70 were approximately fivefold higher (P < 0.05) in S2a/Hsp70 compared with S2a/pMT2 and approximately twofold higher (P < 0.05) following HS in all cells. Coimmunoprecipitation demonstrated that Hsp70 directly binds to SERCA2a. Following HS, maximal SERCA2a activity was reduced ( approximately 52%, P < 0.05) in S2a/pMT2 but was increased ( approximately 33%, P < 0.05) in S2a/Hsp70. Thermal inactivation of SERCA2a in S2a/pMT2 was associated with decreased ( approximately 49%, P < 0.05) binding capacity for fluorescein isothiocyanate (FITC) and increased carbonyl ( approximately 42%, P < 0.05) and nitrotyrosine ( approximately 40%, P < 0.05) levels in SERCA2a. By contrast, the HS-induced increase in maximal SERCA2a activity observed in S2a/Hsp70 corresponded with no change (P > 0.05) in FITC-binding capacity and reductions in carbonyl ( approximately 40%, P < 0.05) and nitrotyrosine ( approximately 23%, P < 0.05) levels in SERCA2a compared with S2a/pMT2. These results show that Hsp70 forms a protective interaction with SERCA2a during HS actually reducing oxidation and nitrosylation of SERCA2a thus increasing its maximal activity.
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Affiliation(s)
- M H Fu
- Dept. of Kinesiology, Univ. of Waterloo, Waterloo, ON, Canada N2L 3G1
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Davis J, Westfall MV, Townsend D, Blankinship M, Herron TJ, Guerrero-Serna G, Wang W, Devaney E, Metzger JM. Designing heart performance by gene transfer. Physiol Rev 2008; 88:1567-651. [PMID: 18923190 DOI: 10.1152/physrev.00039.2007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The birth of molecular cardiology can be traced to the development and implementation of high-fidelity genetic approaches for manipulating the heart. Recombinant viral vector-based technology offers a highly effective approach to genetically engineer cardiac muscle in vitro and in vivo. This review highlights discoveries made in cardiac muscle physiology through the use of targeted viral-mediated genetic modification. Here the history of cardiac gene transfer technology and the strengths and limitations of viral and nonviral vectors for gene delivery are reviewed. A comprehensive account is given of the application of gene transfer technology for studying key cardiac muscle targets including Ca(2+) handling, the sarcomere, the cytoskeleton, and signaling molecules and their posttranslational modifications. The primary objective of this review is to provide a thorough analysis of gene transfer studies for understanding cardiac physiology in health and disease. By comparing results obtained from gene transfer with those obtained from transgenesis and biophysical and biochemical methodologies, this review provides a global view of cardiac structure-function with an eye towards future areas of research. The data presented here serve as a basis for discovery of new therapeutic targets for remediation of acquired and inherited cardiac diseases.
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Affiliation(s)
- Jennifer Davis
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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Vangheluwe P, Raeymaekers L, Dode L, Wuytack F. Modulating sarco(endo)plasmic reticulum Ca2+ ATPase 2 (SERCA2) activity: cell biological implications. Cell Calcium 2008; 38:291-302. [PMID: 16105684 DOI: 10.1016/j.ceca.2005.06.033] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 06/28/2005] [Indexed: 11/20/2022]
Abstract
Of the three mammalian members belonging to the sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) family, SERCA2 is evolutionary the oldest and shows the most wide tissue-expression pattern. Two major SERCA2 splice variants are well-characterized: the muscle-specific isoform SERCA2a and the housekeeping isoform SERCA2b. Recently, several interacting proteins and post-translational modifications of SERCA2 were identified which may modulate the activity of the Ca2+ pump. This review aims to give an overview of the vast literature concerning the cell biological implications of the SERCA2 isoform diversity and the factors regulating SERCA2. Proteins reported to interact with SERCA2 from the cytosolic domain involve the anti-apoptotic Bcl-2, the insulin receptor substrates IRS1/2, the EF-hand Ca2+-binding protein S100A1 and acylphosphatase. We will focus on the very particular position of SERCA2 as an enzyme functioning in a thin, highly fluid, leaky and cholesterol-poor membrane. Possible differential interactions of SERCA2b and SERCA2a with calreticulin, calnexin and ERp57, which could occur within the lumen of the endoplasmic reticulum will be discussed. Reported post-translational modifications possibly affecting pump activity involve N-glycosylation, glutathionylation and Ca2+/calmodulin kinase II-dependent phosphorylation. Finally, the pronounced vulnerability to oxidative damage of SERCA2 appears to be pivotal in the etiology of various pathologies.
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Affiliation(s)
- Peter Vangheluwe
- Laboratory of Physiology, O.&N. Gasthuisberg, K.U. Leuven, Campus Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium
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50
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Morita T, Hussain D, Asahi M, Tsuda T, Kurzydlowski K, Toyoshima C, MacLennan DH. Interaction sites among phospholamban, sarcolipin, and the sarco(endo)plasmic reticulum Ca2+-ATPase. Biochem Biophys Res Commun 2008; 369:188-94. [DOI: 10.1016/j.bbrc.2007.11.098] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 11/15/2007] [Indexed: 12/01/2022]
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