1
|
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.
Collapse
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
| |
Collapse
|
2
|
Chazarin B, Storey KB, Ziemianin A, Chanon S, Plumel M, Chery I, Durand C, Evans AL, Arnemo JM, Zedrosser A, Swenson JE, Gauquelin-Koch G, Simon C, Blanc S, Lefai E, Bertile F. Metabolic reprogramming involving glycolysis in the hibernating brown bear skeletal muscle. Front Zool 2019; 16:12. [PMID: 31080489 PMCID: PMC6503430 DOI: 10.1186/s12983-019-0312-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/08/2019] [Indexed: 12/17/2022] Open
Abstract
Background In mammals, the hibernating state is characterized by biochemical adjustments, which include metabolic rate depression and a shift in the primary fuel oxidized from carbohydrates to lipids. A number of studies of hibernating species report an upregulation of the levels and/or activity of lipid oxidizing enzymes in muscles during torpor, with a concomitant downregulation for glycolytic enzymes. However, other studies provide contrasting data about the regulation of fuel utilization in skeletal muscles during hibernation. Bears hibernate with only moderate hypothermia but with a drop in metabolic rate down to ~ 25% of basal metabolism. To gain insights into how fuel metabolism is regulated in hibernating bear skeletal muscles, we examined the vastus lateralis proteome and other changes elicited in brown bears during hibernation. Results We show that bear muscle metabolic reorganization is in line with a suppression of ATP turnover. Regulation of muscle enzyme expression and activity, as well as of circulating metabolite profiles, highlighted a preference for lipid substrates during hibernation, although the data suggested that muscular lipid oxidation levels decreased due to metabolic rate depression. Our data also supported maintenance of muscle glycolysis that could be fuelled from liver gluconeogenesis and mobilization of muscle glycogen stores. During hibernation, our data also suggest that carbohydrate metabolism in bear muscle, as well as protein sparing, could be controlled, in part, by actions of n-3 polyunsaturated fatty acids like docosahexaenoic acid. Conclusions Our work shows that molecular mechanisms in hibernating bear skeletal muscle, which appear consistent with a hypometabolic state, likely contribute to energy and protein savings. Maintenance of glycolysis could help to sustain muscle functionality for situations such as an unexpected exit from hibernation that would require a rapid increase in ATP production for muscle contraction. The molecular data we report here for skeletal muscles of bears hibernating at near normal body temperature represent a signature of muscle preservation despite atrophying conditions.
Collapse
Affiliation(s)
- Blandine Chazarin
- 1Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France.,10Centre National d'Etudes Spatiales, CNES, F-75001 Paris, France
| | - Kenneth B Storey
- 2Department of Biology, Carleton University, Ottawa, ON K1S 5B6 Canada
| | - Anna Ziemianin
- 1Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France.,10Centre National d'Etudes Spatiales, CNES, F-75001 Paris, France
| | - Stéphanie Chanon
- 3CarMen Laboratory, INSERM 1060, INRA 1397, University of Lyon, F-69600 Oullins, France
| | - Marine Plumel
- 1Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Isabelle Chery
- 1Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Christine Durand
- 3CarMen Laboratory, INSERM 1060, INRA 1397, University of Lyon, F-69600 Oullins, France
| | - Alina L Evans
- 4Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences, Campus Evenstad, NO-2480 Koppang, Norway
| | - Jon M Arnemo
- 4Department of Forestry and Wildlife Management, Inland Norway University of Applied Sciences, Campus Evenstad, NO-2480 Koppang, Norway.,5Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Andreas Zedrosser
- 6Department of Environmental and Health Studies, University College of Southeast Norway, N-3800 Bø, Telemark Norway.,7Institute of Wildlife Biology and Game Management, University of Natural Resources and Life Sciences, A-1180 Vienna, Austria
| | - Jon E Swenson
- 8Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, NO-1432 Ås, Norway.,9Norwegian Institute for Nature Research, NO-7485 Trondheim, Norway
| | | | - Chantal Simon
- 3CarMen Laboratory, INSERM 1060, INRA 1397, University of Lyon, F-69600 Oullins, France
| | - Stephane Blanc
- 1Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Etienne Lefai
- 3CarMen Laboratory, INSERM 1060, INRA 1397, University of Lyon, F-69600 Oullins, France.,Université d'Auvergne, INRA, UNH UMR1019, F-63122 Saint-Genès Champanelle, France
| | - Fabrice Bertile
- 1Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| |
Collapse
|
3
|
Substrate-specific changes in mitochondrial respiration in skeletal and cardiac muscle of hibernating thirteen-lined ground squirrels. J Comp Physiol B 2014; 184:401-14. [PMID: 24408585 DOI: 10.1007/s00360-013-0799-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 12/20/2013] [Accepted: 12/29/2013] [Indexed: 10/25/2022]
Abstract
During torpor, the metabolic rate (MR) of thirteen-lined ground squirrels (Ictidomys tridecemlineatus) is considerably lower relative to euthermia, resulting in part from temperature-independent mitochondrial metabolic suppression in liver and skeletal muscle, which together account for ~40% of basal MR. Although heart accounts for very little (<0.5%) of basal MR, in the present study, we showed that respiration rates were decreased up to 60% during torpor in both subsarcolemmal (SS) and intermyofibrillar (IM) mitochondria from cardiac muscle. We further demonstrated pronounced seasonal (summer vs. winter [i.e., interbout] euthermia) changes in respiration rates in both mitochondrial subpopulations in this tissue, consistent with a shift in fuel use away from carbohydrates and proteins and towards fatty acids and ketones. By contrast, these seasonal changes in respiration rates were not observed in either SS or IM mitochondria isolated from hind limb skeletal muscle. Both populations of skeletal muscle mitochondria, however, did exhibit metabolic suppression during torpor, and this suppression was 2- to 3-fold greater in IM mitochondria, which provide ATP for Ca(2+)- and myosin ATPases, the activities of which are likely quite low in skeletal muscle during torpor because animals are immobile. Finally, these changes in mitochondrial respiration rates were still evident when standardized to citrate synthase activity rather than to total mitochondrial protein.
Collapse
|
4
|
Lazareva MV, Trapeznikova KO, Vikhlyantsev IM, Bobylev AG, Klimov AA, Podlubnaya ZA. Seasonal changes in the isoform composition of the myosin heavy chains in skeletal muscles of hibernating ground squirrels Spermophilus undulatus. Biophysics (Nagoya-shi) 2013. [DOI: 10.1134/s0006350912060085] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
5
|
Rouble AN, Hefler J, Mamady H, Storey KB, Tessier SN. Anti-apoptotic signaling as a cytoprotective mechanism in mammalian hibernation. PeerJ 2013; 1:e29. [PMID: 23638364 PMCID: PMC3628845 DOI: 10.7717/peerj.29] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 01/11/2013] [Indexed: 12/20/2022] Open
Abstract
In the context of normal cell turnover, apoptosis is a natural phenomenon involved in making essential life and death decisions. Apoptotic pathways balance signals which promote cell death (pro-apoptotic pathways) or counteract these signals (anti-apoptotic pathways). We proposed that changes in anti-apoptotic proteins would occur during mammalian hibernation to aid cell preservation during prolonged torpor under cellular conditions that are highly injurious to most mammals (e.g. low body temperatures, ischemia). Immunoblotting was used to analyze the expression of proteins associated with pro-survival in six tissues of thirteen-lined ground squirrels, Ictidomys tridecemlineatus. The brain showed a concerted response to torpor with significant increases in the levels of all anti-apoptotic targets analyzed (Bcl-2, Bcl-xL, BI-1, Mcl-1, cIAP1/2, xIAP) as well as enhanced phosphorylation of Bcl-2 at S70 and T56. Heart responded similarly with most anti-apoptotic proteins elevated significantly during torpor except for Bcl-xL and xIAP that decreased and Mcl-1 that was unaltered. In liver, BI-1 increased whereas cIAP1/2 decreased. In kidney, there was an increase in BI-1, cIAP and xIAP but decreases in Bcl-xL and p-Bcl-2(T56) content. In brown adipose tissue, protein levels of BI-1, cIAP1/2, and xIAP decreased significantly during torpor (compared with euthermia) whereas Bcl-2, Bcl-xL, Mcl-1 were unaltered; however, Bcl-2 showed enhanced phosphorylation at Thr56 but not at Ser70. In skeletal muscle, only xIAP levels changed significantly during torpor (an increase). The data show that anti-apoptotic pathways have organ-specific responses in hibernators with a prominent potential role in heart and brain where coordinated enhancement of anti-apoptotic proteins occurred in response to torpor.
Collapse
Affiliation(s)
- Andrew N Rouble
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, Ontario, Canada K1S 5B6
| | - Joshua Hefler
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, Ontario, Canada K1S 5B6
| | - Hapsatou Mamady
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, Ontario, Canada K1S 5B6
| | - Kenneth B Storey
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, Ontario, Canada K1S 5B6
| | - Shannon N Tessier
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, Ontario, Canada K1S 5B6
| |
Collapse
|
6
|
Basevich EV, Lopina OD, Rubtsov AM. Seasonal changes in microsomal fraction enriched with Na,K-ATPase from kidneys of the ground squirrel Spermophilus undulatus. BIOCHEMISTRY (MOSCOW) 2011; 75:1408-16. [PMID: 21314610 DOI: 10.1134/s0006297910110143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The Na,K-ATPase activity in microsomal fraction isolated from kidneys of winter hibernating ground squirrels was found to be 1.8-2.0-fold lower than that in active animals in summer. This is partially connected with a decrease in Na,K-ATPase protein content in these preparations (by 25%). Using antibodies to different isoforms of Na,K-ATPase α-subunit and analysis of enzyme inhibition by ouabain, it was found that the decrease in Na,K-ATPase activity during hibernation is not connected with change in isoenzyme composition. Seasonal changes of Na,K-ATPase α-subunit phosphorylation level by endogenous protein kinases were not found. Proteins which could be potential regulators of Na,K-ATPase activity were not found among phosphorylated proteins of the microsomes. Analysis of the composition and properties of the lipid phase of microsomes showed that the total level of unsaturation of fatty acids and the lipid/protein ratio are not changed significantly during hibernation, whereas the cholesterol content in preparations from kidneys of hibernating ground squirrels is approximately twice higher than that in preparations from kidneys of active animals. However, using spin and fluorescent probes it was shown that this difference in cholesterol content does not affect the integral membrane microviscosity of microsomes. Using the cross-linking agent cupric phenanthroline, it was shown that Na,K-ATPase in membranes of microsomes from kidneys of hibernating ground squirrels is present in more aggregated state in comparison with membranes of microsomes from kidneys of active animals. We suggest that the decrease in Na,K-ATPase activity in kidneys of ground squirrels during hibernation is mainly connected with the aggregation of proteins in plasma membrane.
Collapse
Affiliation(s)
- E V Basevich
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, Moscow 119991, Russia.
| | | | | |
Collapse
|
7
|
van Breukelen F, Krumschnabel G, Podrabsky JE. Vertebrate cell death in energy-limited conditions and how to avoid it: what we might learn from mammalian hibernators and other stress-tolerant vertebrates. Apoptosis 2010; 15:386-99. [DOI: 10.1007/s10495-010-0467-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
8
|
Ramnanan CJ, McMullen DC, Bielecki A, Storey KB. Regulation of sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) in turtle muscle and liver during acute exposure to anoxia. J Exp Biol 2010; 213:17-25. [DOI: 10.1242/jeb.036087] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
SUMMARY
The freshwater turtle Trachemys scripta elegans naturally tolerates extended periods of anoxia during winter hibernation at the bottom of ice-locked ponds. Survival in this anoxic state is facilitated by a profound depression of metabolic rate. As calcium levels are known to be elevated in anoxic turtles, and ion pumping is an ATP-expensive process, we proposed that activity of the sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) would be reduced in muscle and liver of T. s. elegans during acute (up to 20 h) exposure to anoxia. SERCA activity decreased ∼30% in liver and ∼40% in muscle after 1 h anoxia exposure and was ∼50% lower after 20 h of anoxia exposure in both tissues, even though SERCA protein levels did not change. SERCA kinetic parameters (increased substrate Km values, increased Arrhenius activation energy) were indicative of a less active enzyme form under anoxic conditions. Interestingly, the less active SERCA in anoxic turtles featured greater stability than the enzyme from normoxic animals as determined by both kinetic analysis (effect of low pH and low temperatures on Km MgATP) and conformational resistance to urea denaturation. The quick time course of deactivation and the stable changes in kinetic parameters that resulted suggested that SERCA was regulated by a post-translational mechanism. In vitro experiments indicated that SERCA activity could be blunted by protein phosphorylation and enhanced by dephosphorylation in a tissue-specific manner.
Collapse
Affiliation(s)
- C. J. Ramnanan
- Vanderbilt University School of Medicine, Department of Molecular Physiology, 710 Robinson Research Building, 2200 Pierce Avenue, Nashville, TN 37232, USA
| | - D. C. McMullen
- Stroke Branch, National Institute of Neurological Disorder and Stroke, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - A. Bielecki
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada, K1S 5B6
| | - K. B. Storey
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada, K1S 5B6
| |
Collapse
|
9
|
Storey KB, Storey JM. Tribute to P. L. Lutz: putting life on 'pause'--molecular regulation of hypometabolism. ACTA ACUST UNITED AC 2008; 210:1700-14. [PMID: 17488933 DOI: 10.1242/jeb.02716] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Entry into a hypometabolic state is an important survival strategy for many organisms when challenged by environmental stress, including low oxygen, cold temperatures and lack of food or water. The molecular mechanisms that regulate transitions to and from hypometabolic states, and stabilize long-term viability during dormancy, are proving to be highly conserved across phylogenic lines. A number of these mechanisms were identified and explored using anoxia-tolerant turtles as the model system, particularly from the research contributions made by Dr Peter L. Lutz in his explorations of the mechanisms of neuronal suppression in anoxic brain. Here we review some recent advances in understanding the biochemical mechanisms of metabolic arrest with a focus on ideas such as the strategies used to reorganize metabolic priorities for ATP expenditure, molecular controls that suppress cell functions (e.g. ion pumping, transcription, translation, cell cycle arrest), changes in gene expression that support hypometabolism, and enhancement of defense mechanisms (e.g. antioxidants, chaperone proteins, protease inhibitors) that stabilize macromolecules and promote long-term viability in the hypometabolic state.
Collapse
Affiliation(s)
- Kenneth B Storey
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada.
| | | |
Collapse
|
10
|
Ramnanan CJ, Storey KB. The regulation of thapsigargin-sensitive sarcoendoplasmic reticulum Ca2+-ATPase activity in estivation. J Comp Physiol B 2007; 178:33-45. [PMID: 17690892 DOI: 10.1007/s00360-007-0197-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 07/17/2007] [Accepted: 07/26/2007] [Indexed: 10/23/2022]
Abstract
Estivation (aerobic dormancy) is characterized by sustained metabolic rate depression, which is crucial to survival in the face of unfavorable environmental conditions and enables the preservation of endogenous fuel reserves. Ion pumping is one of the most energetically taxing physiological processes in cells, and ion motive ATPases are likely loci to be differentially regulated in models of metabolic arrest. We proposed that the sarcoendoplasmic reticulum (SER) calcium-ATPase (SERCA) would be deactivated in the estivating desert snail Otala lactea, potentially contributing to the overall suppression of metabolism. SERCA kinetic parameters [decreased maximal velocities, increased substrate K (m) values, increased Arrhenius activation energy (E (a))] were indicative of a less active enzyme in the estivated state. Interestingly, the less active SERCA population in dormant snails featured greater kinetic (K (m) Mg.ATP versus temperature) and conformational (resistance to urea denaturation) stability than that in active snails. Western blotting confirmed that SERCA protein content did not change during estivation. In light of this observation, we proposed that estivation-dependent changes in SERCA activity was due to changes in SERCA phosphorylation state. In vitro studies promoting specific kinase or phosphatase action indicated that decreased SERCA activity in estivation was linked with endogenous kinase activity whereas reactivation of SERCA was facilitated by endogenous protein phosphatases (PP).
Collapse
Affiliation(s)
- Christopher J Ramnanan
- Department of Molecular Physiology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA.
| | | |
Collapse
|
11
|
Storey KB. Anoxia tolerance in turtles: Metabolic regulation and gene expression. Comp Biochem Physiol A Mol Integr Physiol 2007; 147:263-76. [PMID: 17035057 DOI: 10.1016/j.cbpa.2006.03.019] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2005] [Revised: 03/14/2006] [Accepted: 03/24/2006] [Indexed: 01/08/2023]
Abstract
Freshwater turtles of the Trachemys and Chrysemys genera are champion facultative anaerobes able to survive for several months without oxygen during winter hibernation in cold water. They have been widely used as models to identify and understand the molecular mechanisms of natural anoxia tolerance and the molecular basis of the hypoxic/ischemic injuries that occur in oxygen-sensitive systems and underlie medical problems such as heart attack and stroke. Peter L. Lutz spent much of his career investigating turtle anaerobiosis with a particular focus on the mechanisms of brain ion homeostasis and neurotransmitter responses to anoxia exposure and the mechanisms that suppress brain ion channel function and neuronal excitability during anaerobiosis. Our interests intersected over the mechanisms of metabolic rate depression which is key to long term anoxia survival. Studies in my lab have shown that a key mechanism of metabolic arrest is reversible protein phosphorylation which provides coordinated suppression of the rates of multiple ATP-producing, ATP-utilizing and related cellular processes to allow organisms to enter a stable hypometabolic state. Anoxia tolerance is also supported by selective gene expression as revealed by recent studies using cDNA library and DNA array screening. New studies with both adult T. scripta elegans and hatchling C. picta marginata have identified prominent groups of genes that are up-regulated under anoxia in turtle organs, in several cases suggesting aspects of cell function and metabolic regulation that have not previously been associated with anaerobiosis. These groups of anoxia-responsive genes include mitochondrially-encoded subunits of electron transport chain proteins, iron storage proteins, antioxidant enzymes, serine protease inhibitors, transmembrane solute carriers, neurotransmitter receptors and transporters, and shock proteins.
Collapse
Affiliation(s)
- Kenneth B Storey
- Institute of Biochemistry, College of Natural Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6.
| |
Collapse
|
12
|
Storey KB, Storey JM. Metabolic rate depression in animals: transcriptional and translational controls. Biol Rev Camb Philos Soc 2004; 79:207-33. [PMID: 15005178 DOI: 10.1017/s1464793103006195] [Citation(s) in RCA: 424] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Metabolic rate depression is an important survival strategy for many animal species and a common element of hibernation, torpor, aestivation, anaerobiosis, diapause, and anhydrobiosis. Studies of the biochemical mechanisms that regulate reversible transitions to and from hypometabolic states are identifying principles of regulatory control that are conserved across phylogenetic lines and that are broadly applied to the control of multiple cell functions. One such mechanism is reversible protein phosphorylation which is now known to contribute to the regulation of fuel metabolism, to ion channel arrest, and to the suppression of protein synthesis during hypometabolism. The present review focuses on two new areas of research in hypometabolism: (1) the role of differential gene expression in supplying protein products that adjust metabolism or protect cell functions for long-term survival, and (2) the mechanisms of protein life extension in hypometabolism involving inhibitory controls of transcription, translation and protein degradation. Control of translation examines reversible phosphorylation regulation of ribosomal initiation and elongation factors, the dissociation of polysomes and storage of mRNA transcripts during hypometabolism, and control over the translation of different mRNA types by differential sequestering of mRNA into polysome versus monosome fractions. The analysis draws primarily from current research on two animal models, hibernating mammals and anoxia-tolerant molluscs, with selected examples from multiple other sources.
Collapse
Affiliation(s)
- Kenneth B Storey
- College of Natural Sciences, Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6.
| | | |
Collapse
|
13
|
Affiliation(s)
- Kenneth B. Storey
- Institute of Biochemistry, College of Natural Sciences, Carleton University, Ottawa, Ontario, Canada
| |
Collapse
|