Chaperone-mediated coupling of endoplasmic reticulum and mitochondrial Ca2+ channels

Szabadkai, György; Bianchi, Katiuscia; Várnai, Péter; Stefani, Diego De; Wieckowski, Mariusz R.; Cavagna, Dario; Nagy, Anikó Ilona; Balla, Tamás; Meneghesso, Gaudenzio

doi:10.1083/jcb.200608073

Cited by 1,157 publications

(1,057 citation statements)

References 67 publications

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“…21,30,31 Our results show that GSK3β preferentially interacts with IP 3 R1, and can also interacts with IP 3 R2 and IP 3 R3 in cardiac cells (data not shown). In summary, we propose that inhibition of GSK3β might decrease the phosphorylation and the activity of IP 3 R, thereby limiting cytosolic and mitochondrial Ca 2+ overload, possibly contributing to the reduction of both cell death and infarct size at reperfusion.…”

Section: Discussionmentioning

confidence: 68%

“…19,20 Ca 2+ -handling proteins of ER and mitochondria are highly concentrated at mitochondria-associated ER membranes (MAMs), providing a direct and proper mitochondrial Ca 2+ signaling, including VDAC, Grp75 and IP 3 R1. [20][21][22] Here, we provide evidence that, following IR, a fraction of cellular GSK3β is localized at the SR/ER and MAMs. At the MAMs interface, GSK3β can specifically interact and regulate the protein composition of the IP 3 R Ca 2+ channeling complex and modulate Ca 2+ transfer between SR/ER and mitochondria.…”

mentioning

confidence: 59%

“…21 Using in situ proximity ligation assay (PLA), we first validated that GSK3β interacted with IP 3 R, Grp75, VDAC or CypD but not RyR2 and ANT in both adult cardiomyocytes and H9c2 cells (Supplementary Figure S2A). GSK3β inhibitors were used to determine if it might change these protein interactions.…”

Section: Resultsmentioning

confidence: 97%

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The SR/ER-mitochondria calcium crosstalk is regulated by GSK3β during reperfusion injury

Gomez¹,

Thiebaut²,

Paillard³

et al. 2015

Cell Death Differ

105

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Glycogen synthase kinase-3β (GSK3β) is a multifunctional kinase whose inhibition is known to limit myocardial ischemiareperfusion injury. However, the mechanism mediating this beneficial effect still remains unclear. Mitochondria and sarco/ endoplasmic reticulum (SR/ER) are key players in cell death signaling. Their involvement in myocardial ischemia-reperfusion injury has gained recognition recently, but the underlying mechanisms are not yet well understood. We questioned here whether GSK3β might have a role in the Ca 2+ transfer from SR/ER to mitochondria at reperfusion. We showed that a fraction of GSK3β protein is localized to the SR/ER and mitochondria-associated ER membranes (MAMs) in the heart, and that GSK3β specifically interacted with the inositol 1,4,5-trisphosphate receptors (IP 3 Rs) Ca 2+ channeling complex in MAMs. We demonstrated that both pharmacological and genetic inhibition of GSK3β decreased protein interaction of IP 3 R with the Ca 2+ channeling complex, impaired SR/ER Ca 2+ release and reduced the histamine-stimulated Ca 2+ exchange between SR/ER and mitochondria in cardiomyocytes. During hypoxia reoxygenation, cell death is associated with an increase of GSK3β activity and IP 3 R phosphorylation, which leads to enhanced transfer of Ca 2+ from SR/ER to mitochondria. Inhibition of GSK3β at reperfusion reduced both IP 3 R phosphorylation and SR/ER Ca 2+ release, which consequently diminished both cytosolic and mitochondrial Ca 2+ concentrations, as well as sensitivity to apoptosis. We conclude that inhibition of GSK3β at reperfusion diminishes Ca 2+ leak from IP 3 R at MAMs in the heart, which limits both cytosolic and mitochondrial Ca 2+ overload and subsequent cell death. Glycogen synthase kinase-3 (GSK3) was originally identified as a phosphorylating kinase for glycogen synthase. 1,2 It has two isoforms, α and β, that possess strong homology in their kinase domains with, however, distinct functions. 3 GSK3 is constitutively active but it can be inhibited by phosphorylation on serine 21 (Ser21) for GSK3α and Ser9 for GSK3β. 4 In the heart, GSK3β has several important roles in cardiac hypertrophy 5 and ischemia-reperfusion (IR) injury. 6 Accumulating evidence indicates that phospho-Ser9-GSK3β-mediated cytoprotection is achieved by an increased threshold for permeability transition pore (PTP) opening. [6][7][8][9] The mechanism by which GSK3β delays PTP opening still remains unclear. It has been reported that GSK3β could interact with ANT at the inner mitochondrial membrane in the heart 9 and/or to phosphorylate voltage-dependent anion channel (VDAC) and cyclophilin D (CypD) in cancer cells. 10,11 GSK3β also has other proposed mechanisms of action, including a poorly characterized role in calcium (Ca 2+ ) homeostasis regulation 12 and protein-protein interactions, 9 as well as functions in different subcellular fractions such as the nucleus, cytosol and mitochondria. 13 Reperfusion is the most powerful intervention to salvage ischemic myocardium. However, it can also paradoxically lead to ca...

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Section: Discussionmentioning

confidence: 68%

mentioning

confidence: 59%

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The SR/ER-mitochondria calcium crosstalk is regulated by GSK3β during reperfusion injury

Gomez¹,

Thiebaut²,

Paillard³

et al. 2015

Cell Death Differ

105

View full text Add to dashboard Cite

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“…Notably, in response to ArA, we observed a remarkable increase of VDAC at MAMs, according to previous studies demonstrating that under apoptosis-inducing conditions a narrowing of the ER-mitochondria associations occurs, and this is an important step in the execution of some apoptotic mechanisms. [26][27][28][29] To investigate a possible mechanism for ER-PTEN action, we looked for a physical interaction between PTEN and IP3R3, as release of the ER Ca 2 þ through IP3R3 appears to sensitize cells to apoptotic stimuli. 24,30 We performed co-immunoprecipitation experiments of proteins extracted from the ER fraction in basal condition or after ArA treatment, and found that PTEN co-immunoprecipitated with IP3R3, together with Akt, a known iteractor and modulator of IP3R-mediated Ca 2 þ release from the ER.…”

Section: Resultsmentioning

confidence: 99%

Identification of PTEN at the ER and MAMs and its regulation of Ca2+ signaling and apoptosis in a protein phosphatase-dependent manner

et al. 2013

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The tumor suppressor activity of PTEN (phosphatase and tensin homolog deleted on chromosome 10) is thought to be largely attributable to its lipid phosphatase activity. PTEN dephosphorylates the lipid second messenger phosphatidylinositol 3,4,5-trisphosphate to directly antagonize the phosphoinositide 3-kinase-Akt pathway and prevent the activating phosphorylation of Akt. PTEN has also other proposed mechanisms of action, including a poorly characterized protein phosphatase activity, protein-protein interactions, as well as emerging functions in different compartment of the cells such as nucleus and mitochondria. We show here that a fraction of PTEN protein localizes to the endoplasmic reticulum (ER) and mitochondriaassociated membranes (MAMs), signaling domains involved in calcium ( 2 þ ) transfer from the ER to mitochondria and apoptosis induction. We demonstrate that PTEN silencing impairs ER Ca 2 þ release, lowers cytosolic and mitochondrial Ca 2 þ transients and decreases cellular sensitivity to Ca 2 þ -mediated apoptotic stimulation. Specific targeting of PTEN to the ER is sufficient to enhance ER-to-mitochondria Ca 2 þ transfer and sensitivity to apoptosis. PTEN localization at the ER is further increased during Ca 2 þ -dependent apoptosis induction. Importantly, PTEN interacts with the inositol 1,4,5-trisphosphate receptors (IP3Rs) and this correlates with the reduction in their phosphorylation and increased Ca 2 þ release. We propose that ER-localized PTEN regulates Ca 2 þ release from the ER in a protein phosphatase-dependent manner that counteracts Akt-mediated reduction in Ca 2 þ release via IP3Rs. These findings provide new insights into the mechanisms and the extent of PTEN tumor-suppressive functions, highlighting new potential strategies for therapeutic intervention.

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“…Cells were reconstituted with coelenterazine n, following ER Ca 2 þ depletion in a solution containing 0 [Ca 2 þ ], 600 mM EGTA, 1 mM ionomycin, for 1 h at 41C, as previously described. 35 Following reconstitution, cells were washed with KRB (Krebs-Ringer modified buffer: 135 mM NaCl, 5 mM KCl, 1 mM MgSO 4 , 0.4 mM K 2 HPO 4 , 5.5 mM glucose, 20 mM HEPES, pH ¼ 7.4) containing 1 mM EGTA and 2% BSA, and transferred to the perfusion chamber. Light signal was collected in a purpose-built luminometer and calibrated into [Ca 2 þ ] values as previously described.…”

Section: Resultsmentioning

confidence: 99%

Reduction of endoplasmic reticulum Ca2+ levels favors plasma membrane surface exposure of calreticulin

et al. 2007

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Some chemotherapeutic agents can elicit apoptotic cancer cell death, thereby activating an anticancer immune response that influences therapeutic outcome. We previously reported that anthracyclins are particularly efficient in inducing immunogenic cell death, correlating with the pre-apoptotic exposure of calreticulin (CRT) on the plasma membrane surface of anthracyclintreated tumor cells. Here, we investigated the role of cellular Ca 2 þ homeostasis on CRT exposure. A neuroblastoma cell line (SH-SY5Y) failed to expose CRT in response to anthracyclin treatment. This defect in CRT exposure could be overcome by the overexpression of Reticulon-1C, a manipulation that led to a decrease in the Ca 2 þ concentration within the endoplasmic reticulum lumen. The combination of Reticulon-1C expression and anthracyclin treatment yielded more pronounced endoplasmic reticulum Ca 2 þ depletion than either of the two manipulations alone. Chelation of intracellular (and endoplasmic reticulum) Ca 2 þ , targeted expression of the ligand-binding domain of the IP 3 receptor and inhibition of the sarco-endoplasmic reticulum Ca 2 þ -ATPase pump reduced endoplasmic reticulum Ca 2 þ load and promoted pre-apoptotic CRT exposure on the cell surface, in SH-SY5Y and HeLa cells. These results provide evidence that endoplasmic reticulum Ca 2 þ levels control the exposure of CRT. In contrast to prior belief, apoptotic cell death can be immunogenic and hence elicits an active immune response against dying tumor cells. 1 This is therapeutically relevant because immune defects that compromise the response against apoptotic cells reduce the efficacy of anticancer chemotherapy, both in suitable animal models and in patients. 2 We found that anthracyclins and g-irradiation are particularly efficient in inducing immunogenic cell death, at least in mouse models. [3][4][5] The immunogenicity of cellular demise correlates with the exposure of calreticulin (CRT) on the plasma membrane (PM) surface of stressed tumor cells, a phenomenon that manifests before the cells acquire signs of apoptosis such as phosphatidylserine exposure. Inhibition of CRT exposure curtails the capacity of anthracyclin-treated or irradiated tumor cells to vaccinate against cancer and reduces the therapeutic efficacy of anthracyclins on tumors established in immunocompetent hosts. 3-5 Provision of recombinant CRT or drug-mediated enforcement of CRT exposure rendered per se nonimmunogenic chemotherapies (for instance with etoposide and mitomycin C) immunogenic and boosted their therapeutic efficacy. 5 These results suggest that CRT exposure is both necessary and sufficient to render conventional chemotherapies immunogenic.CRT is an abundant Ca 2 þ -binding chaperone that is mostly present in the endoplasmic reticulum (ER) lumen, although it can also be found in other subcellular localizations. 6,7 When present on the surface of damaged cells, it can serve as an 'eat-me' signal and hence facilitate the recognition and later engulfment of the dying cells by macrophages 8 or by dendrit...

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Chaperone-mediated coupling of endoplasmic reticulum and mitochondrial Ca2+ channels

Cited by 1,157 publications

References 67 publications

The SR/ER-mitochondria calcium crosstalk is regulated by GSK3β during reperfusion injury

The SR/ER-mitochondria calcium crosstalk is regulated by GSK3β during reperfusion injury

Identification of PTEN at the ER and MAMs and its regulation of Ca2+ signaling and apoptosis in a protein phosphatase-dependent manner

Reduction of endoplasmic reticulum Ca2+ levels favors plasma membrane surface exposure of calreticulin

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