Simultaneous presence of two distinct endoplasmic-reticulum-type calcium-pump isoforms in human cells. Characterization by radio-immunoblotting and inhibition by 2,5-di-(t-butyl)-1,4-benzohydroquinone

Papp, Béla; Enyedi, Ágnes; Pászty, Katalin; Kovàcs, Tündé; Sarkadi, Balázs; Gárdos, George; Magnier, C; Wuytack, Frank; Enouf, Jocelyne

doi:10.1042/bj2880297

Cited by 105 publications

(78 citation statements)

References 47 publications

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“…It is tempting to speculate that their reduced expression during differentiation reflects selective atrophy of this subcompartment that may account for at least part of the reduced total cell Ca 2ϩ content that we observed. In support of this possibility is evidence that the SERCA2b and SERCA3b Ca 2ϩ transport proteins are associated with different functional pools of intracellular Ca 2ϩ stores, the SERCA3b pool being more sensitive to release by IP 3 (62,63). Therefore, it is possible that the differentiation-induced reduction of SERCA2b may be accompanied by a reduction in the size of its associated Ca 2ϩ pool.…”

Section: Fig 8 Immunoblot Analysis Of Selected Er and Cytosolic Promentioning

confidence: 56%

Regulation of Calreticulin Expression during Induction of Differentiation in Human Myeloid Cells

Clark¹,

Li²,

Pearson³

et al. 2002

Journal of Biological Chemistry

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Induction of differentiation of HL-60 human myeloid cells profoundly affected expression of calreticulin, a Ca2؉ -binding endoplasmic reticulum chaperone. Induction with Me 2 SO or retinoic acid reduced levels of calreticulin protein by ϳ60% within 4 days. Pulse-chase studies indicated that labeled calreticulin decayed at similar rates in differentiated and undifferentiated cells (t1 ⁄2 ϳ4.6 days), but the biosynthetic rate was <10% of control after 4 days. Differentiation also induced a rapid decline in calreticulin mRNA levels (90% reduction after 1 day) without a decrease in transcript stability (t1 ⁄2 ϳ5 h). Nuclear run-on analysis demonstrated rapid downregulation of gene transcription (21% of control at 2 h). Differentiation also greatly reduced the Ca 2؉ content of the cells (25% of control), although residual Ca 2؉ pools remained sensitive to thapsigargin, ionomycin, and inositol trisphosphate. Progressive decreases were also observed in levels of calnexin and ERp57, whereas BiP/ GRP78 and protein disulfide isomerase were only modestly affected. Ultrastructural studies showed a substantial reduction in endoplasmic reticulum content of the cells. Thus, terminal differentiation of myeloid cells was associated with decreased endoplasmic reticulum content, selective reductions in molecular chaperones, and diminished intracellular Ca 2؉ stores, perhaps reflecting an endoplasmic reticulum remodeling program as a prominent feature of granulocytic differentiation.Calreticulin is a major Ca 2ϩ -binding protein present in the lumen of the endoplasmic reticulum (ER) 1 of virtually all cell types (1-3). The cDNA sequence predicts an ϳ47-kDa acidic protein with a zonal structure featuring a globular N-terminal domain, a proline-rich P domain, and a highly acidic C domain terminating in a KDEL motif, the ER retention signal (3, 4).Biophysical studies show calreticulin to be a highly asymmetric molecule consistent with this predicted three domain structure. Calreticulin binds Ca 2ϩ with both high and low affinities and with high capacity. A single high affinity site (K d ϳ1 M) is located within the P domain of the molecule and multiple low affinity sites (K d ϳ2 mM, 20 -25 mol of Ca 2ϩ /mol of protein) are present in the highly acidic C domain (3,4). The N domain contains at least one site for binding Zn 2ϩ , which appears to involve 4 of the histidine residues in this region (5, 6). Binding of these ions affects the conformation and stability of the protein (7).Numerous and apparently unrelated functions have been ascribed to calreticulin since it was first identified, but its roles in the regulation of Ca 2ϩ homeostasis and as a molecular chaperone of nascent glycoproteins are the two functions that have been most extensively characterized. Calreticulin appears to regulate intracellular Ca 2ϩ homeostasis through more than one mechanism. The high Ca 2ϩ -binding capacity of calreticulin suggests that it acts as a Ca 2ϩ store or buffer within the ER, and there is evidence that in at least some cell types it is a main so...

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Section: Fig 8 Immunoblot Analysis Of Selected Er and Cytosolic Promentioning

confidence: 56%

Regulation of Calreticulin Expression during Induction of Differentiation in Human Myeloid Cells

Clark¹,

Li²,

Pearson³

et al. 2002

Journal of Biological Chemistry

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“…The recent observation that NO inhibits the active Ca2+ uptake into platelet membrane vesicles led us to check whether it could also increase the cytosolic Ca2 + concentration, as the well-known inhibitors of the SERCA pumps do (Thastrup, 1987;Thastrup et al, 1990;Papp et al, 1992). A significant rise in [Ca2+] was indeed observed.…”

Section: Discussionmentioning

confidence: 99%

“…as specific inhibitors of the sarco/endoplasmic reticulum Ca2+-ATPases (SERCA pumps) (Papp et al, 1992). These compounds elevate cytosolic [Ca2+] by inhibiting Ca2+ reuptake into the dense tubular system (Thastrup, 1987;Thastrup et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

Influence of authentic nitric oxide on basal cytosolic [Ca²⁺] and Ca²⁺ release from internal stores in human platelets

Sang

Lantoine

Devynck

1996

British J Pharmacology

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Nitric oxide (NO) donors inhibit platelet function and Ca2+ mobilization evoked by different agonists. This led us to investigate the direct effects of authentic NO on basal cytosolic Ca2+ concentration ([Ca2+]i) and on Ca2+ mobilization induced by thrombin or by two inhibitors of intracellular Ca2+‐ATPases, thapsigargin and 2,5‐di‐(t‐butyl)‐l,4‐benzohydroquinone (t‐BuBHQ). Cytosolic Ca2+ concentration was evaluated with Fura‐2, in the absence of Ca2+ influx. Addition of 5 μm NO increased by 48% the basal cytosolic [Ca2+] of resting human platelets whereas a lower concentration (0.1 μm) did not induce significant modifications. This NO‐induced Ca2+ increase was inversely correlated with the basal level of cytosolic [Ca2+]. NO pretreatment for 30 to 120 s decreased by 42 to 57% the transient [Ca2+]i peak evoked by 0.10 u ml−1 thrombin and strongly attenuated the initial rate of [Ca2+]i rise induced by 1 μm thapsigargin or by 20 μm t‐BuBHQ. The two components of the thapsigargin response, the Ca2+ release due to inhibition of Ca2+ pumps and the thromboxane A2‐dependent self‐amplification mechanism, were inhibited by NO. The observation that a subsequent stimulation was still capable of eliciting Ca2+ release suggests the presence of NO‐insensitive Ca2+ stores. These findings indicate that nitric oxide can modulate basal cytosolic [Ca2+] in unstimulated human platelets and decrease the Ca2+ mobilization from NO‐sensitive internal stores evoked by stimulation of receptors or by Ca2+‐ATPase inhibitors. This underlines the important role of nitric oxide in the modulation of platelet Ca2+ handling.

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“…The IID8 antibody recognizes the SERCA 2b isoform at 100 kDa, whereas the PLIM430 antibody, obtained by immunizing with purified platelet internal membrane preparations (19), reacts with a distinct, 97-kDa pump species, temporarily designed as SERCA PLIM430 (17,18). The biochemical characteristics and the intracellular localization of these two pump species are different (17)(18)(19)(20)(21), suggesting that they play functionally distinct roles within the same cell. To better elucidate the functional specialization of the coexpressed calcium pump isoforms, in the present work we investigated the modulation of the expression of these enzymes during in vitro lymphocyte activation, a process where significant changes of cell function, structure, and signaling occur.…”

mentioning

confidence: 99%

“…Previously, we have shown that in human cell lines of hemopoietic origin, isoform-specific anti-SERCA monoclonal antibodies can detect two distinct enzyme species that are coexpressed in the same cells (17,18). The IID8 antibody recognizes the SERCA 2b isoform at 100 kDa, whereas the PLIM430 antibody, obtained by immunizing with purified platelet internal membrane preparations (19), reacts with a distinct, 97-kDa pump species, temporarily designed as SERCA PLIM430 (17,18). The biochemical characteristics and the intracellular localization of these two pump species are different (17)(18)(19)(20)(21), suggesting that they play functionally distinct roles within the same cell.…”

mentioning

confidence: 99%

Modulation of Endoplasmic Reticulum Calcium Pump Expression during T Lymphocyte Activation

Launay

Bobe

Lacabaratz

et al. 1997

Journal of Biological Chemistry

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Calcium mobilization from intracellular storage organelles is a key component of the second messenger system inducing cell activation. Calcium transport ATPases associated with intracellular calcium storage organelles play a major role in controlling this process by accumulating calcium from the cytosol into intracellular calcium pools. In this study the modulation of the expression of the sarco-endoplasmic reticulum calcium transport ATPase (SERCA) isoenzymes has been studied in lymphocytes undergoing phorbol myristate acetate and ionomycin-induced activation. In several T lymphocyte cell lines a combined treatment by the two drugs resulted in an approximately 90% decrease of the expression of the calcium pump isoform recognized by the PLIM430 isoform-specific antibody, whereas the expression of the SERCA 2b isoform was increased approximately 2-fold. Phorbol ester or ionomycin applied separately was ineffective. In Jurkat T cells the downmodulation of expression of the SERCA isoform recognized by the PLIM430 antibody appeared concomitantly with the induction of interleukin-2 expression and could be inhibited by the immunosuppressant drug cyclosporine-A. These data indicate that T cell activation induces a selective and cyclosporine-A-sensitive modulation of the expression of the SERCA calcium pump isoforms. This reflects a profound reorganization of the calcium homeostasis of T cells undergoing activation and may open new avenues in the understanding of the plasticity of the calcium homeostasis of differentiating cells and in the pharmacological modulation of lymphocyte function.Calcium as a second messenger is a key component of the cellular signaling network controlling lymphocyte function (Refs. 1-3 and references therein). Activation of the T cell receptor complex and associated coreceptors by antigen presenting cells leads to the formation of two second messengers, diacylglycerol and inositol 1,4,5-trisphosphate (IP 3 ).1 The formation of diacylglycerol results in the activation of various cellular protein kinase C isoenzymes, and the binding of IP 3 to its receptor induces the release of calcium into the cytosol from intracellular calcium storage organelles (1-3). Calcium mobilization from the endoplasmic reticulum also provokes a calcium influx across the plasma membrane (4 -8). These events lead to the activation of several inducible transcription factors such as NFB, NFAT, or AP-1 (9). The induction of the transcription of activation-associated genes, e.g. the gene coding for IL-2 (9, 10), or the ␣ chain of the IL-2 receptor (11) leads to a profound reorganization of the structure and function of the cell, resulting in an activated phenotype. Endoplasmic reticulum associated calcium pumps (SERCA enzymes) accumulate calcium ions from the cytosol by ATP-dependent active transport into endoplasmic reticulum-associated calcium storage organelles (8). Because the increase of cytosolic calcium concentration, as well as the depletion of intracellular calcium pools, generate several activatory signals (5-8), ...

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Simultaneous presence of two distinct endoplasmic-reticulum-type calcium-pump isoforms in human cells. Characterization by radio-immunoblotting and inhibition by 2,5-di-(t-butyl)-1,4-benzohydroquinone

Cited by 105 publications

References 47 publications

Regulation of Calreticulin Expression during Induction of Differentiation in Human Myeloid Cells

Regulation of Calreticulin Expression during Induction of Differentiation in Human Myeloid Cells

Influence of authentic nitric oxide on basal cytosolic [Ca²⁺] and Ca²⁺ release from internal stores in human platelets

Modulation of Endoplasmic Reticulum Calcium Pump Expression during T Lymphocyte Activation

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Simultaneous presence of two distinct endoplasmic-reticulum-type calcium-pump isoforms in human cells. Characterization by radio-immunoblotting and inhibition by 2,5-di-(t-butyl)-1,4-benzohydroquinone

Cited by 105 publications

References 47 publications

Regulation of Calreticulin Expression during Induction of Differentiation in Human Myeloid Cells

Regulation of Calreticulin Expression during Induction of Differentiation in Human Myeloid Cells

Influence of authentic nitric oxide on basal cytosolic [Ca2+] and Ca2+ release from internal stores in human platelets

Modulation of Endoplasmic Reticulum Calcium Pump Expression during T Lymphocyte Activation

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Influence of authentic nitric oxide on basal cytosolic [Ca²⁺] and Ca²⁺ release from internal stores in human platelets