Localization and quantification of endoplasmic reticulum Ca(2+)-ATPase isoform transcripts

Wu, Kwan‐Dun; Lee, W. S.; Wey, Jane; Bungard, David; Lytton, Jonathan

doi:10.1152/ajpcell.1995.269.3.c775

Cited by 323 publications

(162 citation statements)

References 21 publications

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“…The effect of PMA on the rate of Ca# + uptake also varied with the free Ca# + concentration, but this was observed only in muscle vesicles (Figure 4), not in vesicles derived from blood platelets ( Table 1). This might be related to structural differences between the sarcoplasmic\endoplasmic-reticulum Ca# + -ATPase isoforms and could reflect differences between platelet and muscle cell requirements for cellular Ca# + control [40][41][42].…”

Section: Discussionmentioning

confidence: 99%

Uncoupling of Ca2+ transport ATPase in muscle and blood platelets by diacylglycerol analogues and cyclosporin A antagonism

1997

Biochemical Journal

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The possibility that diacylglycerol analogues might have a wider spectrum of intracellular targets than the well-known protein kinase C was investigated with vesicles containing the Ca# + -ATPase derived from the dense tubular system in platelets and from the sarcoplasmic reticulum of skeletal muscle. The diacylglycerol analogues PMA and 1-oleoyl-2-acetyl-rac-glycerol (OAG) inhibited Ca# + accumulation by these vesicles, an effect that was antagonized by cyclosporin A. The inhibitory activity of PMA and OAG resulted from the uncoupling of the Ca# + -ATPase, characterized by a pronounced inhibition of Ca# + uptake accompanied by a discrete decrease in ATPase activity and by the inhibition of the enzyme's phosphorylation by P i , leading to both a decrease in ATP synthesis and an enhancement of Ca# +

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Section: Discussionmentioning

confidence: 99%

Uncoupling of Ca2+ transport ATPase in muscle and blood platelets by diacylglycerol analogues and cyclosporin A antagonism

1997

Biochemical Journal

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“…SERCAs, which are encoded by three homologous genes (SERCA1, SERCA2, and SERCA3) [3], undergo alternative splicing in different tissues. SERCA2a and b are expressed in the brain, in skeletal and cardiac muscle as well as in all non-muscle tissues [45]. Interestingly, treatments that cause increases in intracellular [Ca 2+ ] can also increase the activity of GSK3β through the dephosphorylation of its inhibitory Ser9 site [38,27,41].…”

Section: Introductionmentioning

confidence: 99%

The protein phosphatase-1/inhibitor-2 complex differentially regulates GSK3 dephosphorylation and increases sarcoplasmic/endoplasmic reticulum calcium ATPase 2 levels

King¹,

Gandy²,

Bijur³

2006

Experimental Cell Research

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The ubiquitously expressed protein glycogen synthase kinase-3 (GSK3) is constitutively active, however its activity is markedly diminished following phosphorylation of Ser21 of GSK3α and Ser9 of GSK3β. Although several kinases are known to phosphorylate Ser21/9 of GSK3, for example Akt, relatively much less is known about the mechanisms that cause the dephosphorylation of GSK3 at Ser21/9. In the present study KCl-induced plasma membrane depolarization of SH-SY5Y cells, which increases intracellular calcium concentrations caused a transient decrease in the phosphorylation of Akt at Thr308 and Ser473, and GSK3 at Ser21/9. Overexpression of the selective protein phosphatase-1 inhibitor protein, inhibitor-2, increased basal GSK3 phosphorylation at Ser21/9 and significantly blocked the KCl-induced dephosphorylation of GSK3β, but not GSK3α. The phosphorylation of Akt was not affected by the overexpression of inhibitor-2. GSK3 activity is known to affect sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) levels. Overexpression of inhibitor-2 or treatment of cells with the GSK3 inhibitors lithium and SB216763 increased the levels of SERCA2. These results indicate that the protein phosphatase-1/inhibitor-2 complex differentially regulates GSK3 dephosphorylation induced by KCl and that GSK3 activity regulates SERCA2 levels. KeywordsAkt; glycogen synthase kinase-3; inhibitor-2; protein phosphatase-1; sarcoplasmic/endoplasmic reticulum calcium ATPase

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“…Most notably, certain isoforms are only expressed in muscle, which contains abundant sarcoplasmic reticulum and high SERCA expression. Specifically, SERCA1a and -1b are expressed exclusively in fast-twitch skeletal muscle, SERCA2a is expressed in cardiac and slow-twitch skeletal muscle, and SERCA2b, -3a, and -3b are expressed in nonmuscle cells (20).…”

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confidence: 99%

Enrichment of Endoplasmic Reticulum with Cholesterol Inhibits Sarcoplasmic-Endoplasmic Reticulum Calcium ATPase-2b Activity in Parallel with Increased Order of Membrane Lipids

Li¹,

Ciani

et al. 2004

Journal of Biological Chemistry

262

219

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Macrophages in advanced atherosclerotic lesions accumulate large amounts of unesterified, or "free," cholesterol (FC). FC accumulation induces macrophage apoptosis, which likely contributes to plaque destabilization. Apoptosis is triggered by the enrichment of the endoplasmic reticulum (ER) with FC, resulting in depletion of ER calcium stores, and induction of the unfolded protein response. To explain the mechanism of ER calcium depletion, we hypothesized that FC enrichment of the normally cholesterol-poor ER membrane inhibits the macrophage ER calcium pump, sarcoplasmic-endoplasmic reticulum calcium ATPase-2b (SERCA2b). FC enrichment of ER membranes to a level similar to that occuring in vivo inhibited both the ATPase activity and calcium sequestration function of SERCA2b. Enrichment of ER with ent-cholesterol or 14:0 -18:0 phosphatidylcholine, which possess the membrane-ordering properties of cholesterol, also inhibited SERCA2b. Moreover, at various levels of FC enrichment of ER membranes, there was a very close correlation between increasing membrane lipid order, as monitored by 16-doxyl-phosphatidycholine electron spin resonance, and SERCA2b inhibition. In view of these data, we speculate that SERCA2b, a conformationally active protein with 11 membrane-spanning regions, loses function due to decreased conformational freedom in FC-ordered membranes. This biophysical model may underlie the critical connection between excess cholesterol, unfolded protein response induction, macrophage death, and plaque destabilization in advanced atherosclerosis.

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Localization and quantification of endoplasmic reticulum Ca(2+)-ATPase isoform transcripts

Cited by 323 publications

References 21 publications

Uncoupling of Ca2+ transport ATPase in muscle and blood platelets by diacylglycerol analogues and cyclosporin A antagonism

Uncoupling of Ca2+ transport ATPase in muscle and blood platelets by diacylglycerol analogues and cyclosporin A antagonism

The protein phosphatase-1/inhibitor-2 complex differentially regulates GSK3 dephosphorylation and increases sarcoplasmic/endoplasmic reticulum calcium ATPase 2 levels

Enrichment of Endoplasmic Reticulum with Cholesterol Inhibits Sarcoplasmic-Endoplasmic Reticulum Calcium ATPase-2b Activity in Parallel with Increased Order of Membrane Lipids

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