Protective effects of Hsp70 on the structure and function of SERCA2a expressed in HEK-293 cells during heat stress

Fu, Ming-Hua; Tupling, A. Russell

doi:10.1152/ajpheart.01276.2008

Cited by 39 publications

(60 citation statements)

References 59 publications

(79 reference statements)

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“…HSP70 exerts a protective effect on the heart (Fu and Tupling, 2009) and brain tissue (Zhao et al, 2006), in addition to playing an important role in immunity. In this regard, HSP70 protects cells from natural killer cells and imparts anti-infective and anti-tumor immunity through its involvement in antigen processing and presentation (Gehrmann et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Heat shock protein 70 polymorphisms in Chinese patients with Graves’ disease

Yp¹,

Tang²,

Bk³

et al. 2015

Genet. Mol. Res.

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ABSTRACT. Graves' disease (GD) is a common autoimmune disease mainly affecting the thyroid. However, the correlation between the development of GD and HSP70 alleles has not been reported in the Chinese population. Therefore, the aim of this study was to investigate the association between HSP70 polymorphisms and GD in the Chinese population. A total of 153 patients with GD treated at the Yan'an Affiliated Hospital of Kunming Medical University between October 2010 and August 2013 were enrolled in this study; one hundred and twenty healthy volunteers were included in the control group. HSP70 polymorphisms at positions HSP70-1 +190, HSP70-2 +1267, and HSP70-hom +2437 were genotyped by polymerase chain reaction-restriction fragment length polymorphism. The distribution of the HSP70-2 +1267 GG genotype allele frequencies among GD and control subjects differed significantly (χ 2 = 20.40, P < 0.001; χ 2 = 18.18, P < 0.001). The G allele of HSP70-2 +1267 (Odds ratio = 0.455, 95% confidence interval: 0.315-0.655) conferred a higher risk of developing GD than the A allele. We observed no significant differences in the allelic frequencies of HSP70-1 +190 and HSP70-hom 18377 HSP70 polymorphisms in Chinese GD patients ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (4): 18376-18383 (2015) +2437. Therefore, the HSP70-2 +1267 GG genotype and the G allele may increase the risk of GD in Chinese subjects. The results of this study may be useful in identifying patients with increased risk of GD, and offer useful reference data for targeted gene therapy of GD in the future.

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Section: Discussionmentioning

confidence: 99%

Heat shock protein 70 polymorphisms in Chinese patients with Graves’ disease

Yp¹,

Tang²,

Bk³

et al. 2015

Genet. Mol. Res.

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“…In this case the HSP72 evidently recognized and bound to targets within the fibers because of alterations in target proteins rather than alterations in the HSP72 itself. It is likely that SERCA is the predominant binding site of the HSP72 in the skinned fibers here, given 1) the propensity of SERCA to bind HSP72 (13,14,45), 2) the comparatively high absolute number of SERCA proteins present in muscle fibers [ϳ100 and 20 -35 mol/kg wet weight in EDL and SOL muscle, respectively (34,49)], and 3) the relatively greater additional HSP72 binding occurring in the EDL fibers compared with SOL fibers (Fig. 6) [see also INTRODUCTION and Ref.…”

Section: Discussionmentioning

confidence: 99%

“…Consistent with this, we have recently shown that in rat SOL muscles heated in vitro to 45°C for 30 min, Ͼ95% of the HSP25 and ␣B-crystallin became tightly bound within the fibers and did not diffuse out even when all internal membranes were dispersed with the detergent Triton X-100 (21). HSP72, in contrast, appears to bind in stress situations primarily to membrane proteins, and in particular has been found to bind to and stabilize the structure and function of the sarco(endo)plasmic reticulum Ca 2ϩ -ATPase pump (SERCA1a and SERCA2a) in skeletal and cardiac muscle following heat stress (13,45). In apparent accord, we have recently reported that the absolute amounts of HSP72 in skeletal muscles are much lower than the density of SERCA pumps [HSP72 content ϳ1.1 and 4.6 mol/kg wet weight in rat extensor digitorum longus (EDL) and SOL muscle (21), and total SERCA content ϳ100 and ϳ20 -35 mol/kg, respectively (34, 49)], that heat treatment of skeletal muscles to 45°C causes tight binding of Ͼ95% of the HSP72 present, and that exposure of such heat-treated fibers to Triton X-100 for 10 min caused diffusional loss of a similar proportion (ϳ50% to 70%) of both the HSP72 and the SERCA (21).…”

mentioning

confidence: 99%

Influences of temperature, oxidative stress, and phosphorylation on binding of heat shock proteins in skeletal muscle fibers

Larkins

Murphy

Lamb

2012

American Journal of Physiology-Cell Physiology

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Larkins NT, Murphy RM, Lamb GD. Influences of temperature, oxidative stress, and phosphorylation on binding of heat shock proteins in skeletal muscle fibers. Am J Physiol Cell Physiol 303: C654 -C665, 2012. First published July 3, 2012; doi:10.1152/ajpcell.00180.2012.-Heat shock proteins (HSPs) help maintain cellular function in stressful situations, but the processes controlling their interactions with target proteins are not well defined. This study examined the binding of HSP72, HSP25, and ␣B-crystallin in skeletal muscle fibers following various stresses. Rat soleus (SOL) and extensor digitorum longus (EDL) muscles were subjected in vitro to heat stress or strongly fatiguing stimulation. Superficial fibers were "skinned" by microdissection and HSP diffusibility assessed from the extent of washout following 10-to 30 min exposure to a physiological intracellular solution. In fibers from nonstressed (control) SOL muscle, Ͼ80% of each HSP is readily diffusible. However, after heating a muscle to 40°C for 30 min ϳ95% of HSP25 and ␣B-crystallin becomes tightly bound at nonmembranous myofibrillar sites, whereas HSP72 bound at membranous sites only after heat treatment to Ն44°C. The ratio of reduced to oxidized cytoplasmic glutathione (GSH:GSSG) decreased approximately two-and fourfold after heating muscles to 40°and 45°C, respectively. The reducing agent dithiothreitol reversed HSP72 binding in heated muscles but had no effect on the other HSPs. Intense in vitro stimulation of SOL muscles, sufficient to elicit substantial oxidation-related loss of maximum force and approximately fourfold decrease in the GSH:GSSG ratio, had no effect on diffusibility of any of the HSPs. When skinned fibers from heat-treated muscles were bathed with additional exogenous HSP72, total binding increased approximately two-and 10-fold, respectively, in SOL and EDL fibers, possibly reflective of the relative sarco(endo)plasmic reticulum Ca 2ϩ -ATPase pump densities in the two fiber types. Phosphorylation at Ser59 on ␣B-crystallin and Ser85 on HSP25 increased with heat treatment but did not appear to determine HSP binding. The findings highlight major differences in the processes controlling binding of HSP72 and the two small HSPs. Binding was not directly related to cytoplasmic oxidative status, but oxidation of cysteine residues influenced HSP72 binding. oxidation; stress response; skinned fiber; chaperones HEAT SHOCK PROTEINS (HSPs) are highly conserved and ubiquitously expressed proteins that act as protein chaperones and in stress situations bind and interact with various proteins to help preserve or restore their function (23,32). A great deal of work in skeletal muscle has focused on the increase in HSP protein and/or mRNA expression levels occurring in hours to days after various stressful stimuli, such as eccentric exercise (11,17,26,27,39), oxidative stress (50), heat (4, 35), and glycogen depletion (12). The present study focuses instead on the acute responses of HSPs to stresses, examining the effects of heat, contraction, and o...

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“…Frozen tissues were homogenized in a solution containing (in mM) 250 sucrose, 5 HEPES, 10 NaN 3, and 0.2 PMSF, using a Polytron homogenizer. Ca 2ϩ -dependent Ca 2ϩ -ATPase activity in homogenates was measured at 37°C, as described previously (12,13). The data were analyzed by nonlinear regression with computer software (GraphPad Software), and the KCa values were calculated using an equation for a general cooperative model for substrate activation.…”

Section: Slnmentioning

confidence: 99%

Enhanced Ca²⁺ transport and muscle relaxation in skeletal muscle from sarcolipin-null mice

Tupling

Bombardier

Gupta

et al. 2011

American Journal of Physiology-Cell Physiology

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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 (ϩdF/dt). Maximum relaxation rates (ϪdF/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 ϩdF/dt; however, forcefrequency curves showed that peak force during a twitch and 10-Hz contraction was lower in Sln-null. Changes in the soleus forcefrequency 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 (ϪdF/dt) in wild type, but not in Sln-null. No compensatory responses were detected in analysis of other Ca 2ϩ regulatory proteins using Western blotting and immunohistochemistry or myosin heavy chain expression using immunofluorescence. These results show that 1) SLN regulates Ca 2ϩ -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. knockout mouse; muscle contractility; isolated skeletal muscle; Ca 2ϩ pump SARCO (ENDO) PLASMIC RETICULUM (SER) Ca 2ϩ -ATPases (SERCAs) are ubiquitously expressed, integral membrane proteins that transport Ca 2ϩ ions from the cytosol to the lumen of the SER. In the heart, a 52 amino acid transmembrane protein, phospholamban (PLN), interacts physically with SERCA2a, lowering the apparent Ca 2ϩ affinity of the PLN-SERCA2a complex (19,30). The inhibited complex is disrupted by phosphorylation of PLN or by elevation of cytosolic Ca 2ϩ , leading to the reversal of SERCA2a inhibition. Sarcolipin (SLN), a 31 amino acid protein, shares substantial identity with PLN in both primary sequence and gene structure (25, 35) and, like PLN, is an effective inhibitor of SERCA molecules (1-3, 16, 24). SLN was originally identified as a proteolipid that copurified with SERCA1a in rabbit fast-twitch skeletal muscle (20). Subsequently, SLN was found to be expressed highly in both human and rabbit fast-twitch skeletal muscle and to a lesser extent in slow-twitch and cardiac muscle, based on mRNA levels (25). SLN expression in the heart is largely restricted to the atrium (22), whereas PLN is highly expressed in the ventricle and not in the atrium ...

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Protective effects of Hsp70 on the structure and function of SERCA2a expressed in HEK-293 cells during heat stress

Cited by 39 publications

References 59 publications

Heat shock protein 70 polymorphisms in Chinese patients with Graves’ disease

Heat shock protein 70 polymorphisms in Chinese patients with Graves’ disease

Influences of temperature, oxidative stress, and phosphorylation on binding of heat shock proteins in skeletal muscle fibers

Enhanced Ca²⁺ transport and muscle relaxation in skeletal muscle from sarcolipin-null mice

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Protective effects of Hsp70 on the structure and function of SERCA2a expressed in HEK-293 cells during heat stress

Cited by 39 publications

References 59 publications

Heat shock protein 70 polymorphisms in Chinese patients with Graves’ disease

Heat shock protein 70 polymorphisms in Chinese patients with Graves’ disease

Influences of temperature, oxidative stress, and phosphorylation on binding of heat shock proteins in skeletal muscle fibers

Enhanced Ca2+ transport and muscle relaxation in skeletal muscle from sarcolipin-null mice

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Enhanced Ca²⁺ transport and muscle relaxation in skeletal muscle from sarcolipin-null mice