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Shan H, Wei J, Zhang M, Lin L, Yan R, Zhu Y, Zhang R. Calreticulin is localized at mitochondria of rat cardiomyocytes and affected by furazolidone. Mol Cell Biochem 2014; 397:125-30. [PMID: 25087122 DOI: 10.1007/s11010-014-2179-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Accepted: 07/24/2014] [Indexed: 11/29/2022]
Abstract
Calreticulin (CRT) is a calcium-buffering protein which is predominantly located in endoplasmic reticulum. In the previous mitochondria proteome analysis, we accidentally found that CRT may be also localized at myocardial mitochondria and was upregulated in a rat model of furazolidone-induced dilated cardiomyopathy. To our knowledge, there has not yet been any report of its presence in mitochondria of any cell types. The present study aimed to determine whether CRT was located at the mitochondria of rat cardiomyocytes and whether the mitochondrial CRT was affected by furazolidone. Mitochondrial preparations were isolated from primary cultured neonatal rat cardiomyocytes and purified by differential centrifugation. The purity of mitochondria was assessed by the reduction or elimination of the immunoreactivities of markers for cytosol, nucleus, sarcolemma, and endoplasmic reticulum. Western blot analysis demonstrated the presence of CRT in purified mitochondria of rat cardiomyocytes. The distribution of CRT to mitochondria was further confirmed by immuno-electron microscopy, flow cytometry, and laser scanning confocal microscopy (double staining with MitoTracker Red and CRT-Alexa Fluor 488). Western blot analysis also demonstrated that the mitochondrial content of CRT was significantly enhanced by furazolidone treatment by 2.73 ± 0.13 fold (P < 0.05) in rat cardiomyocytes, which was verified by immuno-electron microscopy. In summary, the present results suggest that CRT is localized at mitochondria of rat cardiomyocytes and such localization is affected by furazolidone.
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Affiliation(s)
- Hu Shan
- Department of Cardiology, The Second Affiliated Hospital, Xi'an Jiaotong University School of Medicine, 157 Xiwu Road, Xi'an, 710004, Shaanxi, China
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Mahajan L, Gautam P, Dodagatta-Marri E, Madan T, Kishore U. Surfactant protein SP-D modulates activity of immune cells: proteomic profiling of its interaction with eosinophilic cells. Expert Rev Proteomics 2014; 11:355-69. [PMID: 24697551 DOI: 10.1586/14789450.2014.897612] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Surfactant protein D (SP-D), a C-type lectin, is known to protect against lung infection, allergy and inflammation. Its recombinant truncated form comprising homotrimeric neck and CRD region (rhSP-D) has been shown to bring down specific IgE levels, eosinophilia and restore Th2-Th1 homeostasis in murine models of lung hypersensitivity. SP-D knockout mice show intrinsic hypereosinophilia and airway hyper-responsiveness that can be alleviated by rhSP-D. The rhSP-D can bind activated eosinophils, inhibit chemotaxis and degranulation, and selectively induce oxidative burst and apoptosis in sensitized eosinophils. A global proteomics study of rhSP-D-treated eosinophilic cell line AML14.3D10 identified large-scale molecular changes associated with oxidative burst, cell stress and survival-related proteins potentially responsible for apoptosis induction. The data also suggested an involvement of RNA binding- and RNA splicing-related proteins. Thus, the proteomics approach yielded a catalog of differentially expressed proteins that may be protein signatures defining mechanisms of SP-D-mediated maintenance of homeostasis during allergy.
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Affiliation(s)
- Lakshna Mahajan
- CSIR Institute of Genomics and Integrative Biology, Mall road, Delhi 110007, India
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Hughes BG, Fan X, Cho WJ, Schulz R. MMP-2 is localized to the mitochondria-associated membrane of the heart. Am J Physiol Heart Circ Physiol 2013; 306:H764-70. [PMID: 24375642 DOI: 10.1152/ajpheart.00909.2013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Matrix metalloproteinase-2 (MMP-2) has been extensively studied in the context of extracellular matrix remodeling but is also localized within cells and can be activated by prooxidants to proteolyze specific intercellular targets. Although there are reports of MMP-2 in mitochondria, a critical source of cellular oxidative stress, these studies did not take into account the presence within their preparations of the mitochondria-associated membrane (MAM), a subdomain of the endoplasmic reticulum (ER). We hypothesized that MMP-2 is situated in the MAM and therefore investigated its subcellular distribution between mitochondria and the MAM. Immunogold electron microscopy revealed MMP-2 localized in mitochondria of heart sections from mice. In contrast, immunofluorescence analysis of an MMP-2:HaloTag fusion protein expressed in HL-1 cardiomyocytes showed an ER-like distribution, with greater colocalization with an ER marker (protein disulfide isomerase) relative to the mitochondrial marker, MitoTracker red. Although MMP-2 protein and enzymatic activity were present in crude mitochondrial fractions, once these were separated into purified mitochondria and MAM, MMP-2 was principally associated with the latter. Thus, although mitochondria may contain minimal levels of MMP-2, the majority of MMP-2 previously identified as "mitochondrial" is in fact associated with the MAM. We also found that calreticulin, an ER- and MAM-resident Ca(2+) handling protein and chaperone, could be proteolyzed by MMP-2 in vitro. MAM-localized MMP-2 could therefore potentially impact mitochondrial function by affecting ER-mitochondrial Ca(2+) signaling via its proteolysis of calreticulin.
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Affiliation(s)
- Bryan G Hughes
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
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Prell T, Lautenschläger J, Grosskreutz J. Calcium-dependent protein folding in amyotrophic lateral sclerosis. Cell Calcium 2013; 54:132-43. [DOI: 10.1016/j.ceca.2013.05.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 05/16/2013] [Accepted: 05/18/2013] [Indexed: 12/25/2022]
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Phyllanthus Suppresses Prostate Cancer Cell, PC-3, Proliferation and Induces Apoptosis through Multiple Signalling Pathways (MAPKs, PI3K/Akt, NFκB, and Hypoxia). EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:609581. [PMID: 23690850 PMCID: PMC3652183 DOI: 10.1155/2013/609581] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/25/2013] [Accepted: 03/25/2013] [Indexed: 01/21/2023]
Abstract
Phyllanthus is a traditional medicinal plant that has been found to have antihepatitis, antibacterial, and anticancer properties. The present studies were to investigate the in vitro molecular mechanisms of anticancer effects of Phyllanthus (P. amarus, P. niruri, P. urinaria, and P. watsonii) plant extracts in human prostate adenocarcinoma. The cancer ten-pathway reporter array was performed and revealed that the expression of six pathway reporters were significantly decreased (Wnt, NFκB, Myc/Max, hypoxia, MAPK/ERK, and MAPK/JNK) in PC-3 cells after treatment with Phyllanthus extracts. Western blot was conducted and identified several signalling molecules that were affected in the signalling pathways including pan-Ras, c-Raf, RSK, Elk1, c-Jun, JNK1/2, p38 MAPK, c-myc, DSH, β-catenin, Akt, HIF-1α, GSK3β, NFκB p50 and p52, Bcl-2, Bax, and VEGF, in treated PC-3 cells. A proteomics-based approach, 2D gel electrophoresis, was performed, and mass spectrometry (MS/MS) results revealed that there were 72 differentially expressed proteins identified in treated PC-3 cells and were involved in tumour cell adhesion, apoptosis, glycogenesis and glycolysis, metastasis, angiogenesis, and protein synthesis and energy metabolism. Overall, these findings suggest that Phyllanthus can interfere with multiple signalling cascades involved in tumorigenesis and be used as a potential therapeutic candidate for treatment of cancer.
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Ward JM, Rider V, Abdou NI, Kimler B. Estradiol differentially regulates calreticulin: a potential link with abnormal T cell function in systemic lupus erythematosus? Lupus 2013; 22:583-96. [PMID: 23535532 DOI: 10.1177/0961203313482742] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Systemic lupus erythematosus (SLE) is an autoimmune disease that affects women nine times more often than men. The present study investigates estradiol-dependent control of the calcium-buffering protein, calreticulin, to gain further insight into the molecular basis of abnormal T cell signaling in SLE T cells. METHODS T cells were purified from blood samples obtained from healthy females and SLE patients. Calreticulin expression was quantified by real-time polymerase chain amplification. Calreticulin and estrogen receptor-α were co-precipitated and analyzed by Western blotting to determine if the proteins associate in T cells. RESULTS Calreticulin expression increased (p = 0.034) in activated control T cells, while estradiol decreased (p = 0.044) calreticulin in resting T cells. Calreticulin expression decreased in activated SLE T cell samples and increased in approximately 50% of resting T cell samples. Plasma estradiol was similar (p > 0.05) among SLE patients and control volunteers. Estrogen receptor-α and calreticulin co-precipitated from nuclear and cytoplasmic T cell compartments. CONCLUSIONS The results indicate that estradiol tightly regulates calreticulin expression in normal human T cells, and the dynamics are different between activated and resting T cells. The absence of this tight regulation in SLE T cells could contribute to abnormal T cell function.
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Affiliation(s)
- J M Ward
- Department of Biology, Pittsburg State University, Pittsburg, Kansas 66762, USA
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57
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Zamanian M, Veerakumarasivam A, Abdullah S, Rosli R. Calreticulin and cancer. Pathol Oncol Res 2013; 19:149-54. [PMID: 23392843 DOI: 10.1007/s12253-012-9600-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 12/21/2012] [Indexed: 01/05/2023]
Abstract
Calreticulin (CRT) as a multi-functional endoplasmic reticulum protein is involved in a spectrum of cellular processes which ranges from calcium homeostasis and chaperoning to cell adhesion and finally malignant formation and progression. Previous studies have shown a contributing role for CRT in a range of different cancers. This present review will focus on the possible roles of CRT in the progression of malignant proliferation and the mechanisms involved in its contribution to cancer invasion.
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Affiliation(s)
- Mohammadreza Zamanian
- Genetic Medicine Research Center, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor Darul Ehsan, Malaysia
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58
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Lee D, Michalak M. Calcium and bioenergetics: from endoplasmic reticulum to mitochondria. Anim Cells Syst (Seoul) 2012. [DOI: 10.1080/19768354.2012.685181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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59
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Zhang Q, Lu YX, Xu WH. Integrated Proteomic and Metabolomic Analysis of Larval Brain Associated with Diapause Induction and Preparation in the Cotton Bollworm, Helicoverpa armigera. J Proteome Res 2012; 11:1042-53. [DOI: 10.1021/pr200796a] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Qi Zhang
- State Key
Laboratory of Biocontrol, School of Life
Sciences, Sun Yat-Sen (Zhongshan) University, Guangzhou, China
| | - Yu-Xuan Lu
- State Key
Laboratory of Biocontrol, School of Life
Sciences, Sun Yat-Sen (Zhongshan) University, Guangzhou, China
| | - Wei-Hua Xu
- State Key
Laboratory of Biocontrol, School of Life
Sciences, Sun Yat-Sen (Zhongshan) University, Guangzhou, China
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61
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Sutendra G, Dromparis P, Wright P, Bonnet S, Haromy A, Hao Z, McMurtry MS, Michalak M, Vance JE, Sessa WC, Michelakis ED. The role of Nogo and the mitochondria-endoplasmic reticulum unit in pulmonary hypertension. Sci Transl Med 2011; 3:88ra55. [PMID: 21697531 DOI: 10.1126/scitranslmed.3002194] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pulmonary arterial hypertension (PAH) is caused by excessive proliferation of vascular cells, which occlude the lumen of pulmonary arteries (PAs) and lead to right ventricular failure. The cause of the vascular remodeling in PAH remains unknown, and the prognosis of PAH remains poor. Abnormal mitochondria in PAH PA smooth muscle cells (SMCs) suppress mitochondria-dependent apoptosis and contribute to the vascular remodeling. We hypothesized that early endoplasmic reticulum (ER) stress, which is associated with clinical triggers of PAH including hypoxia, bone morphogenetic protein receptor II mutations, and HIV/herpes simplex virus infections, explains the mitochondrial abnormalities and has a causal role in PAH. We showed in SMCs from mice that Nogo-B, a regulator of ER structure, was induced by hypoxia in SMCs of the PAs but not the systemic vasculature through activation of the ER stress-sensitive transcription factor ATF6. Nogo-B induction increased the distance between the ER and mitochondria and decreased ER-to-mitochondria phospholipid transfer and intramitochondrial calcium. In addition, we noted inhibition of calcium-sensitive mitochondrial enzymes, increased mitochondrial membrane potential, decreased mitochondrial reactive oxygen species, and decreased mitochondria-dependent apoptosis. Lack of Nogo-B in PASMCs from Nogo-A/B-/- mice prevented these hypoxia-induced changes in vitro and in vivo, resulting in complete resistance to PAH. Nogo-B in the serum and PAs of PAH patients was also increased. Therefore, triggers of PAH may induce Nogo-B, which disrupts the ER-mitochondria unit and suppresses apoptosis. This could rescue PASMCs from death during ER stress but enable the development of PAH through overproliferation. The disruption of the ER-mitochondria unit may be relevant to other diseases in which Nogo is implicated, such as cancer or neurodegeneration.
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Affiliation(s)
- Gopinath Sutendra
- Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2B7, Canada
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62
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George I, Sabbah HN, Xu K, Wang N, Wang J. β-Adrenergic receptor blockade reduces endoplasmic reticulum stress and normalizes calcium handling in a coronary embolization model of heart failure in canines. Cardiovasc Res 2011; 91:447-55. [DOI: 10.1093/cvr/cvr106] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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63
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Zhang W, Ambati S, Della-Fera MA, Choi YH, Baile CA, Andacht TM. Leptin modulated changes in adipose tissue protein expression in ob/ob mice. Obesity (Silver Spring) 2011; 19:255-61. [PMID: 20725060 DOI: 10.1038/oby.2010.166] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Comparative proteomic analyses were performed in adipose tissue of leptin-deficient ob/ob mice treated with leptin or control buffer in order to identify the protein expression changes as the potential targets of leptin. Mice were treated with either phosphate-buffered saline (control) or 10 µg/day leptin for 14 days via subcutaneous osmotic minipumps. Total protein from white adipose tissue was extracted and labeled with different fluorescent cyanine dyes for analysis by two-dimensional difference gel electrophoresis (DIGE). Spots that were differentially expressed and appeared to have sufficient material for mass spectrometry analysis were picked and digested with trypsin and subjected to MALDI-TOF MS for protein identification. Twelve functional protein groups were found differentially expressed in adipose tissue of leptin-treated vs. control ob/ob mice, including molecular chaperones and redox proteins such as calreticulin (CALR), protein disulfide isomerase-associated 3 (PDIA3), prohibitin (PHB), and peroxiredoxin-6 (PRDX6); cytoskeleton proteins such as β actin, desmin, and α-tubulin; and some other proteins. The mRNA levels of CALR, PDIA3, and PHB were measured by real-time reverse transcription-PCR and found to be upregulated (P < 0.05), consistent with the fold change in protein expression level. Our findings suggest that leptin's effects on lipid metabolism and apoptosis may be mediated in part by alterations in expression of molecular chaperones and redox proteins for regulating endoplasmic reticulum stress and cytoskeleton proteins for regulating mitochondrial morphology.
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Affiliation(s)
- Wei Zhang
- Department of Animal and Dairy Science, Athens, Georgia, USA
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64
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Milli A, Perego P, Beretta GL, Corvo A, Righetti PG, Carenini N, Corna E, Zuco V, Zunino F, Cecconi D. Proteomic Analysis of Cellular Response to Novel Proapoptotic Agents Related to Atypical Retinoids in Human IGROV-1 Ovarian Carcinoma Cells. J Proteome Res 2010; 10:1191-207. [DOI: 10.1021/pr100963n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Alberto Milli
- Dipartimento di Biotecnologie, Laboratorio di Proteomica e Spettrometria di Massa, University of Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Paola Perego
- Fondazione IRCCS Istituto Nazionale dei Tumori, via Amadeo 42, 20133, Milano, Italy
| | - Giovanni L. Beretta
- Fondazione IRCCS Istituto Nazionale dei Tumori, via Amadeo 42, 20133, Milano, Italy
| | - Alice Corvo
- Dipartimento di Biotecnologie, Laboratorio di Proteomica e Spettrometria di Massa, University of Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Pier Giorgio Righetti
- Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Via Mancinelli 7, 20131, Milano, Italy
| | - Nives Carenini
- Fondazione IRCCS Istituto Nazionale dei Tumori, via Amadeo 42, 20133, Milano, Italy
| | - Elisabetta Corna
- Fondazione IRCCS Istituto Nazionale dei Tumori, via Amadeo 42, 20133, Milano, Italy
| | - Valentina Zuco
- Fondazione IRCCS Istituto Nazionale dei Tumori, via Amadeo 42, 20133, Milano, Italy
| | - Franco Zunino
- Fondazione IRCCS Istituto Nazionale dei Tumori, via Amadeo 42, 20133, Milano, Italy
| | - Daniela Cecconi
- Dipartimento di Biotecnologie, Laboratorio di Proteomica e Spettrometria di Massa, University of Verona, Strada le Grazie 15, 37134, Verona, Italy
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Abstract
Ca2+ is a universal signalling molecule that affects a variety of cellular processes including cardiac development. The majority of intracellular Ca2+ is stored in the endoplasmic and sarcoplasmic reticulum of muscle and non-muscle cells. Calreticulin is a well studied Ca2+-buffering protein in the endoplasmic reticulum, and calreticulin deficiency is embryonic lethal due to impaired cardiac development. Despite calsequestrin being the most abundant Ca2+-buffering protein in the sarcoplasmic reticulum, viability is maintained in embryos without calsequestrin and normal Ca2+ release and contractile function is observed. The Ca2+ homeostasis regulated by the endoplasmic and sarcoplasmic reticulum is critical for the development and proper function of the heart.
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Affiliation(s)
- Dukgyu Lee
- Department of Biochemistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta, Canada T6G2H7
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66
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A proteomic study on a human osteosarcoma cell line Saos-2 treated with diallyl trisulfide. Anticancer Drugs 2009; 20:702-12. [DOI: 10.1097/cad.0b013e32832e89c7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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67
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Rivers DB, Dani MP, Richards EH. The mode of action of venom from the endoparasitic wasp Pimpla hypochondriaca (hymenoptera: ichneumonidae) involves Ca+2-dependent cell death pathways. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2009; 71:173-190. [PMID: 19479735 DOI: 10.1002/arch.20314] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The endoparasitoid Pimpla hypochondriaca injects venom during oviposition to condition its lepidopteran hosts. Venom is a complex mixture of proteins and polypeptides, many of which have been identified as enzymes, including phenoloxidase, endopeptidase, aminopeptidase, hydrolase, and angiotensin-converting enzyme. Constituents of the venom have been shown to possess cytolytic and paralytic activity, but the modes of action of factor(s) responsible for exerting such effects have not been deciphered. In this study, we examined the mode of action of isolated venom using cultured cells (BTI-TN-5B1-4). A series of blockage and inhibition assays were performed using a potent inhibitor (phenylthiourea, PTU) of venom phenoloxidase, and anti-calreticulin antibodies. Monolayers exposed to venom alone were highly susceptible with more than 84.6+/-2.3% dead within 15 min. Susceptible cells displayed a retraction of cytoplasmic extensions, rounding, and swelling prior to lysis in more than half (55.7+/-1.7%) of the dying cells. Within 15 min of exposure to venom, cells displayed qualitative increases in [Ca(+2)](i) as evidenced by staining with the calcium-sensitive probe fluo-4 AM, and mitochondrial membrane potential (DeltaPsi(m)) was undetectable by 5 min post-treatment with venom. These venom-mediated changes occurred regardless of whether an external source of calcium was present, or whether venom was pre-treated with PTU. In contrast, venom toxicity was attenuated by treatment with anti-calreticulin antibodies. Not only did fewer cells die when exposed to antibody-treated venom but also cell swelling diminished and no increases in intracellular calcium were detected. A possible mode of action for the venom is discussed.
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Affiliation(s)
- David B Rivers
- Department of Biology, Loyola College in Maryland, Baltimore, Maryland 21210, USA.
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68
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Novel function of perforin in negatively regulating CD4(+) T cell activation by affecting calcium signaling. Cell Res 2009; 19:816-27. [PMID: 19290021 DOI: 10.1038/cr.2009.32] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Perforin is a pore-forming protein engaged mainly in mediating target T cell death and is employed by cytotoxic T lymphocytes (CTLs) and natural killer cells. However, whether it also plays a role in conventional CD4(+) T cell function remains unclear. Here we report that in perforin-deficient (PKO) mice, CD4(+) T cells are hyperproliferative in response to T cell receptor (TCR) stimulation. This feature of hyperproliferation is accompanied by the enhancement both in cell division and in IL-2 secretion. It seems that the perforin deficiency does not influence T cell development in thymus spleen and lymph node. In vivo, perforin deficiency results in increased antigen-specific T cell proliferation and antibody production. Furthermore, PKO mice are more susceptible to experimental autoimmune uveitis. To address the molecular mechanism, we found that after TCR stimulation, CD4(+) T cells from PKO mice display an increased intracellular calcium flux and subsequently enhance activation of transcription factor NFAT1. Our results indicate that perforin plays a negative role in regulating CD4(+) T cell activation and immune response by affecting TCR-dependent Ca(2+) signaling.
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69
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Ahmad S, Ahmad A, Dremina ES, Sharov VS, Guo X, Jones TN, Loader JE, Tatreau JR, Perraud AL, Schöneich C, Randell SH, White CW. Bcl-2 suppresses sarcoplasmic/endoplasmic reticulum Ca2+-ATPase expression in cystic fibrosis airways: role in oxidant-mediated cell death. Am J Respir Crit Care Med 2009; 179:816-26. [PMID: 19201925 DOI: 10.1164/rccm.200807-1104oc] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Modulation of the activity of sarcoendoplasmic reticulum calcium ATPase (SERCA) can profoundly affect Ca(2+) homeostasis. Although altered calcium homeostasis is a characteristic of cystic fibrosis (CF), the role of SERCA is unknown. OBJECTIVES This study provides a comprehensive investigation of expression and activity of SERCA in CF airway epithelium. A detailed study of the mechanisms underlying SERCA changes and its consequences was also undertaken. METHODS Lung tissue samples (bronchus and bronchiole) from subjects with and without CF were evaluated by immunohistochemistry. Protein and mRNA expression in primary non-CF and CF cells was determined by Western and Northern blots. MEASUREMENTS AND MAIN RESULTS SERCA2 expression was decreased in bronchial and bronchiolar epithelia of subjects with CF. SERCA2 expression in lysates of polarized tracheobronchial epithelial cells from subjects with CF was decreased by 67% as compared with those from subjects without CF. Several non-CF and CF airway epithelial cell lines were also probed. SERCA2 expression and activity were consistently decreased in CF cell lines. Adenoviral expression of mutant F508 cystic fibrosis transmembrane regulator gene (CFTR), inhibition of CFTR function pharmacologically (CFTR(inh)172), or stable expression of antisense oligonucleotides to inhibit CFTR expression caused decreased SERCA2 expression. In CF cells, SERCA2 interacted with Bcl-2, leading to its displacement from caveolae-related domains of endoplasmic reticulum membranes, as demonstrated in sucrose density gradient centrifugation and immunoprecipitation studies. Knockdown of SERCA2 using siRNA enhanced epithelial cell death due to ozone, hydrogen peroxide, and TNF-alpha. CONCLUSIONS Reduced SERCA2 expression may alter calcium signaling and apoptosis in CF. These findings decrease the likelihood of therapeutic benefit of SERCA inhibition in CF.
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Affiliation(s)
- Shama Ahmad
- Department of Pediatrics, National Jewish Medical and Research Center, A440, 1400 Jackson Street, Denver, CO 80206, USA.
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Michalak M, Groenendyk J, Szabo E, Gold L, Opas M. Calreticulin, a multi-process calcium-buffering chaperone of the endoplasmic reticulum. Biochem J 2009; 417:651-666. [DOI: 10.1042/bj20081847] [Citation(s) in RCA: 528] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Calreticulin is an ER (endoplasmic reticulum) luminal Ca2+-buffering chaperone. The protein is involved in regulation of intracellular Ca2+ homoeostasis and ER Ca2+ capacity. The protein impacts on store-operated Ca2+ influx and influences Ca2+-dependent transcriptional pathways during embryonic development. Calreticulin is also involved in the folding of newly synthesized proteins and glycoproteins and, together with calnexin (an integral ER membrane chaperone similar to calreticulin) and ERp57 [ER protein of 57 kDa; a PDI (protein disulfide-isomerase)-like ER-resident protein], constitutes the ‘calreticulin/calnexin cycle’ that is responsible for folding and quality control of newly synthesized glycoproteins. In recent years, calreticulin has been implicated to play a role in many biological systems, including functions inside and outside the ER, indicating that the protein is a multi-process molecule. Regulation of Ca2+ homoeostasis and ER Ca2+ buffering by calreticulin might be the key to explain its multi-process property.
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Affiliation(s)
- Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada, T6G 2H7
| | - Jody Groenendyk
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada, T6G 2H7
| | - Eva Szabo
- Laboratory of Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
| | - Leslie I. Gold
- Departments of Medicine and Pathology, New York University School of Medicine, New York, NY 10016, U.S.A
| | - Michal Opas
- Laboratory of Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
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71
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TRPP2 channels regulate apoptosis through the Ca2+ concentration in the endoplasmic reticulum. EMBO J 2009; 28:490-9. [PMID: 19153608 DOI: 10.1038/emboj.2008.307] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Accepted: 12/22/2008] [Indexed: 12/12/2022] Open
Abstract
Ca(2+) is an important signalling molecule that regulates multiple cellular processes, including apoptosis. Although Ca(2+) influx through transient receptor potential (TRP) channels in the plasma membrane is known to trigger cell death, the function of intracellular TRP proteins in the regulation of Ca(2+)-dependent signalling pathways and apoptosis has remained elusive. Here, we show that TRPP2, the ion channel mutated in autosomal dominant polycystic kidney disease (ADPKD), protects cells from apoptosis by lowering the Ca(2+) concentration in the endoplasmic reticulum (ER). ER-resident TRPP2 counteracts the activity of the sarcoendoplasmic Ca(2+) ATPase by increasing the ER Ca(2+) permeability. This results in diminished cytosolic and mitochondrial Ca(2+) signals upon stimulation of inositol 1,4,5-trisphosphate receptors and reduces Ca(2+) release from the ER in response to apoptotic stimuli. Conversely, knockdown of TRPP2 in renal epithelial cells increases ER Ca(2+) release and augments sensitivity to apoptosis. Our findings indicate an important function of ER-resident TRPP2 in the modulation of intracellular Ca(2+) signalling, and provide a molecular mechanism for the increased apoptosis rates in ADPKD upon loss of TRPP2 channel function.
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72
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Mohan C, Lee GM. Calnexin overexpression sensitizes recombinant CHO cells to apoptosis induced by sodium butyrate treatment. Cell Stress Chaperones 2009; 14:49-60. [PMID: 18663604 PMCID: PMC2673906 DOI: 10.1007/s12192-008-0054-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 05/07/2008] [Accepted: 05/14/2008] [Indexed: 12/12/2022] Open
Abstract
Sodium butyrate (NaBu) can enhance the expression of foreign genes in recombinant Chinese hamster ovary (rCHO) cells, but it can also inhibit cell growth and induce cellular apoptosis. In this study, the potential role of calnexin (Cnx) expression in rCHO cells treated with 5 mM NaBu was investigated for rCHO cells producing tumor necrosis factor receptor FC. To regulate the Cnx expression level, a tetracycline-inducible system was used. Clones with different Cnx expression levels were selected and investigated. With regard to productivity per cell (q (p)), NaBu enhanced the q (p) by over twofold. Under NaBu treatment, Cnx overexpression further enhanced the q (p) by about 1.7-fold. However, under NaBu stress, the cells overexpressing Cnx showed a poorer viability profile with a consistent difference of over 25% in the viability when compared to the Cnx-repressed condition. This drop in the viability was attributed to increased apoptosis seen in these cells as evidenced by enhanced poly (ADP-ribose) polymerase cleavage and cytochrome C release. Ca(2+) localization staining and subsequent confocal imaging revealed elevated cytosolic Ca(2+) ([Ca(2+)](c)) in the Cnx-overexpressing cells when compared to the Cnx-repressed condition, thus endorsing the increased apoptosis observed in these cells. Taken together, Cnx overexpression not only improved the q (p) of cells treated with NaBu, but it also sensitized cells to apoptosis.
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Affiliation(s)
- Chaya Mohan
- Department of Biological Sciences, KAIST, 373-1 Kusong-Dong, Yusong-Gu, Daejon, 305-701 South Korea
| | - Gyun Min Lee
- Department of Biological Sciences, KAIST, 373-1 Kusong-Dong, Yusong-Gu, Daejon, 305-701 South Korea
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73
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Xiao D, Zhao F, Song YY, Meng FL, He LH, Zhang HF, Zhang JZ. Influence of Helicobacter pylori CagA on Ca 2+-associated phosphorylated proteins of AGS cells. Shijie Huaren Xiaohua Zazhi 2008; 16:3610-3615. [DOI: 10.11569/wcjd.v16.i32.3610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To analyze the differential expression of Ca2+-associated protein (CagA) in human gastric adenocarcinoma epithelial cells (AGS) infected with H. pylori CagA and to move forward a single step for revealing CagA pathogenic mechanism.
METHODS: Proteins of AGS cells infected with H. pylori 26695 for 4 h, AGS cells infected withH. pylori 26695 △CagA for 4 h, and the uninfected AGS cells as a control group were extracted. Phosphorylated proteins were enriched by metal ion affinity adsorption enrichment techniques. The samples were separated by 2-dimensional polyacrylamide gel electrophoresis (2-DE) technique. Computer assisted image analysis was used to analyze the differential proteomic expression. The significantly differentially expressed proteins were unambiguously assigned identities by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF/TOF).
RESULTS: AGS cells treated with H. pylori △CagA showed the same expression as those cultured with the same period of AGS cells. However, expression of AGS cells treated with H. pylori △CagA had significant changes, indicating such a change was simply caused by CagA. Nineteen such protein spots were identified, of which, 3 protein spots were Ca2+-associated. Calcium-binding protein (nucleobindin-2 precursor, CALNUC) had almost the same expression either in AGS cells or 2-D gel under interaction of H. pylori △CagA with the AGS. However, such protein expression was markedly decreased following interaction between H. pylori and AGS.
CONCLUSION: CRT and CALNUC may affect the calcium homeostasis of endoplasmic reticulum, mitochondria and golgi, and then induce the apoptosis or proliferation pathway, which thus serves as a predisposing factor for gastritis, gastric ulcer and gastric cancer.
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74
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Pienaar IS, Daniels WMU, Götz J. Neuroproteomics as a promising tool in Parkinson's disease research. J Neural Transm (Vienna) 2008; 115:1413-30. [PMID: 18523721 PMCID: PMC2862282 DOI: 10.1007/s00702-008-0070-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Accepted: 05/14/2008] [Indexed: 12/21/2022]
Abstract
Despite the vast number of studies on Parkinson's disease (PD), its effective diagnosis and treatment remains unsatisfactory. Hence, the relentless search for an optimal cure continues. The emergence of neuroproteomics, with its sophisticated techniques and non-biased ability to quantify proteins, provides a methodology with which to study the changes in neurons that are associated with neurodegeneration. Neuroproteomics is an emerging tool to establish disease-associated protein profiles, while also generating a greater understanding as to how these proteins interact and undergo post-translational modifications. Furthermore, due to the advances made in bioinformatics, insight is created concerning their functional characteristics. In this review, we first summarize the most prominent proteomics techniques and then discuss the major advances in the fast-growing field of neuroproteomics in PD. Ultimately, it is hoped that the application of this technology will lead towards a presymptomatic diagnosis of PD, and the identification of risk factors and new therapeutic targets at which pharmacological intervention can be aimed.
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Affiliation(s)
- Ilse S Pienaar
- Department of Medical Physiology, University of Stellenbosch, Matieland, South Africa.
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75
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Fedrizzi L, Lim D, Carafoli E, Brini M. Interplay of the Ca2+-binding Protein DREAM with Presenilin in Neuronal Ca2+ Signaling. J Biol Chem 2008; 283:27494-27503. [DOI: 10.1074/jbc.m804152200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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76
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Schenk U, Westendorf AM, Radaelli E, Casati A, Ferro M, Fumagalli M, Verderio C, Buer J, Scanziani E, Grassi F. Purinergic control of T cell activation by ATP released through pannexin-1 hemichannels. Sci Signal 2008; 1:ra6. [PMID: 18827222 DOI: 10.1126/scisignal.1160583] [Citation(s) in RCA: 333] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
T cell receptor (TCR) stimulation results in the influx of Ca(2+), which is buffered by mitochondria and promotes adenosine triphosphate (ATP) synthesis. We found that ATP released from activated T cells through pannexin-1 hemichannels activated purinergic P2X receptors (P2XRs) to sustain mitogen-activated protein kinase (MAPK) signaling. P2XR antagonists, such as oxidized ATP (oATP), blunted MAPK activation in stimulated T cells, but did not affect the nuclear translocation of the transcription factor nuclear factor of activated T cells, thus promoting T cell anergy. In vivo administration of oATP blocked the onset of diabetes mediated by anti-islet TCR transgenic T cells and impaired the development of colitogenic T cells in inflammatory bowel disease. Thus, pharmacological inhibition of ATP release and signaling could be beneficial in treating T cell-mediated inflammatory diseases.
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Affiliation(s)
- Ursula Schenk
- Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland
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77
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Pallero MA, Elzie CA, Chen J, Mosher DF, Murphy-Ullrich JE. Thrombospondin 1 binding to calreticulin-LRP1 signals resistance to anoikis. FASEB J 2008; 22:3968-79. [PMID: 18653767 DOI: 10.1096/fj.07-104802] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Anoikis, apoptotic cell death due to loss of cell adhesion, is critical for regulation of tissue homeostasis in tissue remodeling. Fibrogenesis is associated with reduced fibroblast apoptosis. The matricellular protein thrombospondin 1 (TSP1) regulates cell adhesion and motility during tissue remodeling and in fibrogenesis. The N-terminal domain of TSP1 binds to the calreticulin-LRP1 receptor co-complex to signal down-regulation of cell adhesion and increased cell motility through focal adhesion disassembly. TSP1 signaling through calreticulin-LRP1 activates cell survival signals such as PI3-kinase. Therefore, we tested the hypothesis that TSP1 supports cell survival under adhesion-independent conditions to facilitate tissue remodeling. Here, we show that platelet TSP1, its N-terminal domain (NoC1) as a recombinant protein, or a peptide comprising the calreticulin-LRP1 binding site [amino acids 17-35 (hep I)] in the N-terminal domain promotes fibroblast survival under anchorage-independent conditions. TSP1 activates Akt and decreases apoptotic signaling through caspase 3 and PARP1 in suspended fibroblasts. Inhibition of PI3K/Akt activity blocks TSP1-mediated anchorage-independent survival. Fibroblasts lacking LRP1 or expressing calreticulin lacking the TSP1 binding site do not respond to TSP1 with anchorage-independent survival. These data define a novel role for TSP1 signaling through the calreticulin/LRP1 co-complex in tissue remodeling and fibrotic responses through stimulation of anoikis resistance.-Pallero, M. A., Elzie, C. A., Chen, J., Mosher, D. F., Murphy-Ullrich, J. E. Thrombospondin 1 binding to calreticulin-LRP1 signals resistance to anoikis.
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Affiliation(s)
- Manuel A Pallero
- Department of Pathology, VH 668 1530 3rd Ave., South, Birmingham, AL 35294-0019, USA
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78
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Xu C, Xu W, Palmer AE, Reed JC. BI-1 regulates endoplasmic reticulum Ca2+ homeostasis downstream of Bcl-2 family proteins. J Biol Chem 2008; 283:11477-84. [PMID: 18299329 DOI: 10.1074/jbc.m708385200] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
BI-1 (Bax inhibitor-1) is an evolutionarily conserved multitransmembrane protein that resides in the endoplasmic reticulum (ER) and that has documented cytoprotective functions in both animals and plants. Recent studies indicate that BI-1 shares in common with Bcl-2/Bax family proteins the ability to regulate the amounts of Ca(2+) that can be released from the ER by agents, such as the ER-Ca(2+)-ATPase (SERCA) inhibitor thapsigargin (TG). Using an ER-targeted, Ca(2+) indicator (cameleon), with characteristics optimized for measuring ER Ca(2+) ([Ca(2+)](er)), we studied the effects of BI-1 on [Ca(2+)](er) in resting and TG-treated cells. Similar to cells overexpressing antiapoptotic Bcl-2 or Bcl-X(L), overexpression of BI-1 resulted in lower resting [Ca(2+)](er), with concomitantly less Ca(2+) released into the cytosol upon stimulation by TG and with a higher rate of Ca(2+) leakage from the ER. Co-expression of SERCA restored levels of [Ca(2+)](er) to normal, showing opposing actions of the ER-Ca(2+)ATPase and BI-1 on ER Ca(2+) homeostasis. Conversely, cells with deficient BI-1 have increased [Ca(2+)](er), and release more Ca(2+) into the cytosol when challenged with TG. In BI-1-deficient cells, Bcl-X(L) fails to reduce [Ca(2+)](er), indicating that BI-1 functions downstream of Bcl-X(L). In bax(-/-)bak(-/-) double knock-out cells, both BI-1 and Bcl-X(L) retained their ability to reduce [Ca(2+)](er), suggesting that BI-1 and Bcl-X(L) operate downstream of or parallel to Bax/Bak. The findings reveal a hierarchy of functional interactions of BI-1 with Bcl-2/Bax family proteins in regulating ER Ca(2+) homeostasis.
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Affiliation(s)
- Chunyan Xu
- Program on Apoptosis and Cell Death Research, Burnham Institute for Medical Research, La Jolla, California 92037, USA
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79
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Spät A, Szanda G, Csordás G, Hajnóczky G. High- and low-calcium-dependent mechanisms of mitochondrial calcium signalling. Cell Calcium 2008; 44:51-63. [PMID: 18242694 DOI: 10.1016/j.ceca.2007.11.015] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2007] [Revised: 11/23/2007] [Accepted: 11/30/2007] [Indexed: 11/30/2022]
Abstract
The Ca(2+) coupling between endoplasmic reticulum (ER) and mitochondria is central to multiple cell survival and cell death mechanisms. Cytoplasmic [Ca(2+)] ([Ca(2+)](c)) spikes and oscillations produced by ER Ca(2+) release are effectively delivered to the mitochondria. Propagation of [Ca(2+)](c) signals to the mitochondria requires the passage of Ca(2+) across three membranes, namely the ER membrane, the outer mitochondrial membrane (OMM) and the inner mitochondrial membrane (IMM). Strategic positioning of the mitochondria by cytoskeletal transport and interorganellar tethers provides a means to promote the local transfer of Ca(2+) between the ER membrane and OMM. In this setting, even >100 microM [Ca(2+)] may be attained to activate the low affinity mitochondrial Ca(2+) uptake. However, a mitochondrial [Ca(2+)] rise has also been documented during submicromolar [Ca(2+)](c) elevations. Evidence has been emerging that Ca(2+) exerts allosteric control on the Ca(2+) transport sites at each membrane, providing mechanisms that may facilitate the Ca(2+) delivery to the mitochondria. Here we discuss the fundamental mechanisms of ER and mitochondrial Ca(2+) transport, particularly the control of their activity by Ca(2+) and evaluate both high- and low-[Ca(2+)]-activated mitochondrial calcium signals in the context of cell physiology.
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Affiliation(s)
- András Spät
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary.
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80
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Lutter D, Ugocsai P, Grandl M, Orso E, Theis F, Lang EW, Schmitz G. Analyzing M-CSF dependent monocyte/macrophage differentiation: expression modes and meta-modes derived from an independent component analysis. BMC Bioinformatics 2008; 9:100. [PMID: 18279525 PMCID: PMC2277398 DOI: 10.1186/1471-2105-9-100] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 02/17/2008] [Indexed: 01/17/2023] Open
Abstract
Background The analysis of high-throughput gene expression data sets derived from microarray experiments still is a field of extensive investigation. Although new approaches and algorithms are published continuously, mostly conventional methods like hierarchical clustering algorithms or variance analysis tools are used. Here we take a closer look at independent component analysis (ICA) which is already discussed widely as a new analysis approach. However, deep exploration of its applicability and relevance to concrete biological problems is still missing. In this study, we investigate the relevance of ICA in gaining new insights into well characterized regulatory mechanisms of M-CSF dependent macrophage differentiation. Results Statistically independent gene expression modes (GEM) were extracted from observed gene expression signatures (GES) through ICA of different microarray experiments. From each GEM we deduced a group of genes, henceforth called sub-mode. These sub-modes were further analyzed with different database query and literature mining tools and then combined to form so called meta-modes. With them we performed a knowledge-based pathway analysis and reconstructed a well known signal cascade. Conclusion We show that ICA is an appropriate tool to uncover underlying biological mechanisms from microarray data. Most of the well known pathways of M-CSF dependent monocyte to macrophage differentiation can be identified by this unsupervised microarray data analysis. Moreover, recent research results like the involvement of proliferation associated cellular mechanisms during macrophage differentiation can be corroborated.
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Affiliation(s)
- Dominik Lutter
- Institute for Clinical Chemistry and Laboratory Medicine, University of Regensburg, D-93042 Regensburg, Germany.
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81
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Joseph SK, Hajnóczky G. IP3 receptors in cell survival and apoptosis: Ca2+ release and beyond. Apoptosis 2008; 12:951-68. [PMID: 17294082 DOI: 10.1007/s10495-007-0719-7] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP(3)Rs) serve to discharge Ca(2+) from ER stores in response to agonist stimulation. The present review summarizes the role of these receptors in models of Ca(2+)-dependent apoptosis. In particular we focus on the regulation of IP(3)Rs by caspase-3 cleavage, cytochrome c, anti-apoptotic proteins and Akt kinase. We also address the evidence that some of the effects of IP(3)Rs in apoptosis may be independent of their ion-channel function. The role of IP(3)Rs in delivering Ca(2+) to the mitochondria is discussed from the perspective of the factors determining inter-organellar dynamics and the spatial proximity of mitochondria and ER membranes.
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Affiliation(s)
- Suresh K Joseph
- Department of Pathology & Cell Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA.
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82
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Liu X, Wu X, Cai L, Sun S. CALRETICULIN DOWNREGULATION IS ASSOCIATED WITH FGF-2-INDUCED ANGIOGENESIS THROUGH CALCINEURIN PATHWAY IN ISCHEMIC MYOCARDIUM. Shock 2008; 29:140-8. [PMID: 17693930 DOI: 10.1097/shk.0b013e318123e822] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Fibroblast growth factor 2 (FGF-2) plays an integral role in therapeutic angiogenesis associated with myocardial infarct healing. Calcium (Ca(2+)) is one of the most universal important signaling molecules that affect cell proliferation and angiogenesis. Calreticulin (CRT), a 46-kd (Ca(2+)) -binding chaperone found mainly in the endoplasmic reticulum, plays an important role in regulating calcium homeostasis. The role of CRT in FGF-2-induced angiogenesis and its signaling pathways in ischemic myocardium are not clear. For this study, two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization mass spectrometry were used to analyze CRT's differential expression in myocardial microvascular endothelial cells treated with or without FGF-2. Western blotting analysis was used to detect the expression of CRT and calcineurin (CaN) in sham-operated, FGF-2-, or saline intramyocardially injected myocardium. It is found that FGF-2 induced angiogenesis after sustained ischemia with downregulation of CRT expression and upregulation of CaN expression in myocardium. The CRT expression was negatively correlated to angiogenesis. Furthermore, overexpression of CRT or inhibition of CaN with cyclosporine A abolishes FGF-2-induced microvascular endothelial cells proliferation and CaN expression. The results indicate that intramyocardial administration of FGF-2 decreases myocardial CRT expression in parallel with myocardial angiogenesis in ischemic myocardium. The study further indicates that Ca(2+)/CaN signaling pathway may be involved in CRT-related angiogenesis.
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Affiliation(s)
- Xiuhua Liu
- Department of Pathophysiology, PLA General Hospital, Beijing, China.
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83
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Okumoto S, Takanaga H, Frommer WB. Quantitative imaging for discovery and assembly of the metabo-regulome. THE NEW PHYTOLOGIST 2008; 180:271-295. [PMID: 19138219 PMCID: PMC2663047 DOI: 10.1111/j.1469-8137.2008.02611.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Little is known about regulatory networks that control metabolic flux in plant cells. Detailed understanding of regulation is crucial for synthetic biology. The difficulty of measuring metabolites with cellular and subcellular precision is a major roadblock. New tools have been developed for monitoring extracellular, cytosolic, organellar and vacuolar ion and metabolite concentrations with a time resolution of milliseconds to hours. Genetically encoded sensors allow quantitative measurement of steady-state concentrations of ions, signaling molecules and metabolites and their respective changes over time. Fluorescence resonance energy transfer (FRET) sensors exploit conformational changes in polypeptides as a proxy for analyte concentrations. Subtle effects of analyte binding on the conformation of the recognition element are translated into a FRET change between two fused green fluorescent protein (GFP) variants, enabling simple monitoring of analyte concentrations using fluorimetry or fluorescence microscopy. Fluorimetry provides information averaged over cell populations, while microscopy detects differences between cells or populations of cells. The genetically encoded sensors can be targeted to subcellular compartments or the cell surface. Confocal microscopy ultimately permits observation of gradients or local differences within a compartment. The FRET assays can be adapted to high-throughput analysis to screen mutant populations in order to systematically identify signaling networks that control individual steps in metabolic flux.
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Affiliation(s)
- Sakiko Okumoto
- Plant Pathology, Physiology, and Weed Science Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Hitomi Takanaga
- Carnegie Institution for Science, Department of Plant Biology, 260 Panama St., Stanford, CA 94305, USA
| | - Wolf B. Frommer
- Carnegie Institution for Science, Department of Plant Biology, 260 Panama St., Stanford, CA 94305, USA
- Joint Bioenergy Institute, Feedstocks Division, Emerystation East, 5885 Hollis Street Emeryville, CA 94608, USA
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84
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Okunaga T, Urata Y, Goto S, Matsuo T, Mizota S, Tsutsumi K, Nagata I, Kondo T, Ihara Y. Calreticulin, a molecular chaperone in the endoplasmic reticulum, modulates radiosensitivity of human glioblastoma U251MG cells. Cancer Res 2007; 66:8662-71. [PMID: 16951181 DOI: 10.1158/0008-5472.can-05-4256] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Radiotherapy is the primary and most important adjuvant therapy for malignant gliomas. Although the mechanism of radiation resistance in gliomas has been studied for decades, it is still not clear how the resistance is related with functions of molecular chaperones in the endoplasmic reticulum. Calreticulin (CRT) is a Ca(2+)-binding molecular chaperone in the endoplasmic reticulum. Recently, it was reported that changes in intracellular Ca(2+) homeostasis play a role in the modulation of apoptosis. In the present study, we found that the level of CRT was higher in neuroglioma H4 cells than in glioblastoma cells (U251MG and T98G), and was well correlated with the sensitivity to gamma-irradiation. To examine the role of CRT in the radiosensitivity of malignant gliomas, the CRT gene was introduced into U251MG cells, which express low levels of CRT, and the effect of overexpression of CRT on the radiosensitivity was examined. The cells transfected with the CRT gene exhibited enhanced radiation-induced apoptosis compared with untransfected control cells. In CRT-overexpressing cells, cell survival signaling via Akt was markedly suppressed. Furthermore, the gene expression of protein phosphatase 2Ac alpha (PP2Ac alpha), which is responsible for the dephosphorylation and inactivation of Akt, was up-regulated in CRT-overexpressing cells, and the regulation was dependent on Ca(2+). Thus, overexpression of CRT modulates radiation-induced apoptosis by suppressing Akt signaling through the up-regulation of PP2Ac alpha expression via altered Ca(2+) homeostasis. These results show the novel mechanism by which CRT is involved in the regulation of radiosensitivity and radiation-induced apoptosis in malignant glioma cells.
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Affiliation(s)
- Tomohiro Okunaga
- Department of Biochemistry and Molecular Biology in Disease, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, 852-8523 Nagasaki, Japan
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85
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Biswas C, Ostrovsky O, Makarewich C, Wanderling S, Gidalevitz T, Argon Y. The peptide-binding activity of GRP94 is regulated by calcium. Biochem J 2007; 405:233-41. [PMID: 17411420 PMCID: PMC1904529 DOI: 10.1042/bj20061867] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
GRP94 (glucose-regulated protein of 94 kDa) is a major luminal constituent of the endoplasmic reticulum with known high capacity for calcium in vivo and a peptide-binding activity in vitro. In the present study, we show that Ca2+ regulates the ability of GRP94 to bind peptides. This effect is due to a Ca2+-binding site located in the charged linker domain of GRP94, which, when occupied, enhances the association of peptides with the peptide-binding site in the N-terminal domain of the protein. We further show that grp94-/- cells are hypersensitive to perturbation of intracellular calcium and thus GRP94 is important for cellular Ca2+ storage.
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Affiliation(s)
- Chhanda Biswas
- *Division of Cell Pathology, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104, U.S.A
- †Department of Pathology, University of Chicago, Chicago, IL 60637, U.S.A
| | - Olga Ostrovsky
- *Division of Cell Pathology, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104, U.S.A
| | - Catherine A. Makarewich
- *Division of Cell Pathology, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104, U.S.A
| | - Sherry Wanderling
- †Department of Pathology, University of Chicago, Chicago, IL 60637, U.S.A
| | - Tali Gidalevitz
- †Department of Pathology, University of Chicago, Chicago, IL 60637, U.S.A
| | - Yair Argon
- *Division of Cell Pathology, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104, U.S.A
- †Department of Pathology, University of Chicago, Chicago, IL 60637, U.S.A
- To whom correspondence should be addressed (email )
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86
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Ni M, Lee AS. ER chaperones in mammalian development and human diseases. FEBS Lett 2007; 581:3641-51. [PMID: 17481612 PMCID: PMC2040386 DOI: 10.1016/j.febslet.2007.04.045] [Citation(s) in RCA: 586] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 04/13/2007] [Accepted: 04/18/2007] [Indexed: 12/16/2022]
Abstract
The field of endoplasmic reticulum (ER) stress in mammalian cells has expanded rapidly during the past decade, contributing to understanding of the molecular pathways that allow cells to adapt to perturbations in ER homeostasis. One major mechanism is mediated by molecular ER chaperones which are critical not only for quality control of proteins processed in the ER, but also for regulation of ER signaling in response to ER stress. Here, we summarized the properties and functions of GRP78/BiP, GRP94/gp96, GRP170/ORP150, GRP58/ERp57, PDI, ERp72, calnexin, calreticulin, EDEM, Herp and co-chaperones SIL1 and P58(IPK) and their role in development and diseases. Many of the new insights are derived from recently constructed mouse models where the genes encoding the chaperones are genetically altered, providing invaluable tools for examining the physiological involvement of the ER chaperones in vivo.
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Affiliation(s)
| | - Amy S. Lee
- *Department of Biochemistry and Molecular Biology and the USC/Norris Comprehensive Cancer Center, Keck School of Medicine of the University of Southern California, 1441 Eastlake Ave., Los Angeles, CA 90089-9176. Tel.: 323-865-0507; Fax: 323-865-0094; E-mail:
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Hayashida Y, Urata Y, Muroi E, Kono T, Miyata Y, Nomata K, Kanetake H, Kondo T, Ihara Y. Calreticulin Represses E-cadherin Gene Expression in Madin-Darby Canine Kidney Cells via Slug. J Biol Chem 2006; 281:32469-84. [PMID: 16943193 DOI: 10.1074/jbc.m607240200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calreticulin (CRT) is a multifunctional Ca(2+)-binding molecular chaperone in the endoplasmic reticulum. In mammals, the expression level of CRT differs markedly in a variety of organs and tissues, suggesting that CRT plays a specific role in each cell type. In the present study, we focused on CRT functions in the kidney, where overall expression of CRT is quite low, and established CRT-overexpressing kidney epithelial cell-derived Madin-Darby canine kidney cells by gene transfection. We demonstrated that, in CRT-overexpressing cells, the morphology was apparently changed, and the original polarized epithelial cell phenotype was destroyed. Furthermore, CRT-overexpressing cells showed enhanced migration through Matrigel-coated Boyden chamber wells, compared with controls. E-cadherin expression was significantly suppressed at the protein and transcriptional levels in CRT-overexpressing cells compared with controls. On the other hand, the expression of mesenchymal protein markers, such as N-cadherin and fibronectin, was up-regulated. We also found that the expression of Slug, a repressor of the E-cadherin promoter, was up-regulated by overexpression of CRT through altered Ca(2+) homeostasis, and this led to enhanced binding of Slug to the E-box element in the E-cadherin promoter. Thus, we conclude that CRT regulates the epithelial-mesenchymal transition-like change of cellular phenotype by modulating the Slug/E-cadherin pathway through altered Ca(2+) homeostasis in cells, suggesting a novel function of CRT in cell-cell interaction of epithelial cells.
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Affiliation(s)
- Yasushi Hayashida
- Department of Biochemistry and Molecular Biology in Disease, Atomic Bomb Disease Institute, and Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
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88
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Gold LI, Rahman M, Blechman KM, Greives MR, Churgin S, Michaels J, Callaghan MJ, Cardwell NL, Pollins AC, Michalak M, Siebert JW, Levine JP, Gurtner GC, Nanney LB, Galiano RD, Cadacio CL. Overview of the role for calreticulin in the enhancement of wound healing through multiple biological effects. J Investig Dermatol Symp Proc 2006; 11:57-65. [PMID: 17069011 DOI: 10.1038/sj.jidsymp.5650011] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Calreticulin (CRT), an intracellular chaperone protein crucial for the proper folding and transport of proteins through the endoplasmic reticulum, has more recent acclaim as a critical regulator of extracellular functions, particularly in mediating cellular migration and as a requirement for phagocytosis of apoptotic cells. Consistent with these functions, we show that the topical application of CRT has profound effects on the process of wound healing by causing a dose-dependent increase in epithelial migration and granulation tissue formation in both murine and porcine normal and impaired animal models of skin injury. These effects of CRTare substantiated, in vitro, as we show that CRT strongly induces cell migration/wound closure of human keratinocytes and fibroblasts, using a wound/scratch plate assay, and stimulates cellular proliferation of human keratinocytes, fibroblasts, and vascular endothelial cells, providing mechanistic insight into how CRT functions in repair. Similarly, in both animal models, the histology of the wounds show marked proliferation of basal keratinocytes and dermal fibroblasts, dense cellularity of the dermis with notably increased numbers of macrophages and well-organized collagen fibril deposition. Thus, CRT profoundly affects the wound healing process by recruiting cells essential for repair into the wound, stimulating cell growth, and increasing extracellular matrix production.
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Affiliation(s)
- Leslie I Gold
- Department of Medicine, New York University School of Medicine, New York, New York 10016, USA.
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89
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Williams DB. Beyond lectins: the calnexin/calreticulin chaperone system of the endoplasmic reticulum. J Cell Sci 2006; 119:615-23. [PMID: 16467570 DOI: 10.1242/jcs.02856] [Citation(s) in RCA: 341] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Calnexin and calreticulin are related proteins that comprise an ER chaperone system that ensures the proper folding and quality control of newly synthesized glycoproteins. The specificity for glycoproteins is conferred by a lectin site that recognizes an early oligosaccharide processing intermediate on the folding glycoprotein, Glc1Man9GlcNAc2. In addition, calnexin and calreticulin possess binding sites for ATP, Ca2+, non-native polypeptides and ERp57, an enzyme that catalyzes disulfide bond formation, reduction and isomerization. Recent studies have revealed the locations of some of these ligand-binding sites and have provided insights into how they contribute to overall chaperone function. In particular, the once controversial non-native-polypeptide-binding site has now been shown to function both in vitro and in cells. Furthermore, there is clear evidence that ERp57 participates in glycoprotein biogenesis either alone or in tandem with calnexin and calreticulin.
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Affiliation(s)
- David B Williams
- Department of Biochemistry and Immunology, University of Toronto, Toronto, Ontario, Canada, M5S 1A8.
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90
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Southall TD, Terhzaz S, Cabrero P, Chintapalli VR, Evans JM, Dow JAT, Davies SA. Novel subcellular locations and functions for secretory pathway Ca2+/Mn2+-ATPases. Physiol Genomics 2006; 26:35-45. [PMID: 16609144 DOI: 10.1152/physiolgenomics.00038.2006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Secretory pathway Ca2+/Mn2+-ATPases (SPCAs) are important for maintenance of cellular Ca2+and Mn2+homeostasis, and, to date, all SPCAs have been found to localize to the Golgi apparatus. The single Drosophila SPCA gene ( SPoCk) was identified by an in silico screen for novel Ca2+-ATPases. It encoded three SPoCk isoforms with novel, distinct subcellular specificities in the endoplasmic reticulum (ER) and peroxisomes in addition to the Golgi. Furthermore, expression of the peroxisome-associated SPoCk isoform was sexually dimorphic. Overexpression of organelle-specific SPoCk isoforms impacted on cytosolic Ca2+handling in both cultured Drosophila cells and a transporting epithelium, the Drosophila Malpighian (renal) tubule. Specifically, the ER isoform impacted on inositol ( 1 , 4 , 5 )-trisphosphate-mediated Ca2+signaling and the Golgi isoform impacted on diuresis, whereas the peroxisome isoform colocalized with Ca2+“spherites” and impacted on calcium storage and transport. Interfering RNA directed against the common exons of the three SPoCk isoforms resulted in aberrant Ca2+signaling and abolished neuropeptide-stimulated diuresis by the tubule. SPoCk thus contributed to both of the contrasting requirements for Ca2+in transporting epithelia: to transport or store Ca2+in bulk without compromising its use as a signal.
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Affiliation(s)
- Tony D Southall
- Division of Molecular Genetics, Anderson College Complex, University of Glasgow, Glasgow, United Kingdom
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91
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Abstract
The endoplasmic reticulum (ER) lumen, which actively monitors the synthesis, folding, and modification of newly synthesized transmembrane and secretory proteins as well as lipids, is quite sensitive to homeostatic perturbations. The biochemical, molecular, and physiological events that elevate cellular ER stress levels and disrupt Ca2+ homeostasis trigger secondary reactions. These reactions are factors in the ongoing neurological pathology contributing to the continual tissue loss. However, the cells are not without defensive systems. One of the reactive mechanisms, the unfolded protein response (UPR), when evoked, provides some measure of protection, unless the stress conditions become prolonged or overwhelming. UPR activation occurs when key ER membrane-bound sensor proteins detect the excess accumulation of misfolded or unfolded proteins within the ER lumen. The activation of these sensors leads to a general protein translation shut-down, transcriptional induction, and translation of select proteins to deal with the difficult and miscreant protein or to encourage their degradation so they will do no harm. If the stress is prolonged, caspase-12, along with other apoptotic proteins, are activated, triggering programmed cell death. UPR, once considered to be a rather simple response, can now be characterized as a multifaceted labyrinth of reactions that continues expanding as research intensifies. This review will examine what has been learned to date about how this highly efficient and specific signaling pathway copes with ER stress, by centering on the basic components, their roles, and the complex interactions engendered. Finally, the UPR impact in various central nervous system injuries is summarized.
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Affiliation(s)
- Stephen F Larner
- Center for Traumatic Brain Injury Studies, Department of Neuroscience, McKnight Brain Institute of the University of Florida, Gainesville, Florida 32610, USA.
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92
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Jakobs S. High resolution imaging of live mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:561-75. [PMID: 16750866 DOI: 10.1016/j.bbamcr.2006.04.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 04/12/2006] [Accepted: 04/13/2006] [Indexed: 11/26/2022]
Abstract
Classically, mitochondria have been studied by biochemical, genetic and electron microscopic approaches. In the last two decades, it became evident that mitochondria are highly dynamic organelles that are frequently dividing and fusing, changing size and shape and traveling long distances throughout the life of a cell. The study of the complex structural changes of mitochondria in vivo became possible with the advent of fluorescent labeling techniques in combination with live cell imaging microscopy. This review aims to provide an overview on novel fluorescent markers that are used in combination with mitochondrial fusion assays and various live cell microscopy techniques to study mitochondrial dynamics. In particular, approaches to study the movement of mitochondrial proteins and novel imaging techniques (FRET imaging-, 4Pi- and STED-microscopy) that provide high spatial resolution are considered.
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Affiliation(s)
- Stefan Jakobs
- Max-Planck-Institute for Biophysical Chemistry, Department of NanoBiophotonics, Mitochondrial Structure and Dynamics Group, Am Fassberg 11, 37077 Goettingen, Germany.
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93
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Walter L, Hajnóczky G. Mitochondria and endoplasmic reticulum: the lethal interorganelle cross-talk. J Bioenerg Biomembr 2006; 37:191-206. [PMID: 16167176 DOI: 10.1007/s10863-005-6600-x] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The fundamental contribution of the mitochondria and ER to the decision made on the cell's fate has been increasingly recognized. This progress has illuminated the need for the mechanisms these organelles use to initiate and to propagate apoptotic signals. The toolbox of the mitochondria and ER is evolutionary conserved, overlapping and complementary. Furthermore, mitochondria are often closely associated with the ER providing the conditions for a local and privileged communication between the two organelles. The present review is concerned with the spatially and temporally coordinated utilization of Bcl-2 family proteins and Ca(2+) by the mitochondria and ER to control the membrane permeabilization in the mitochondria and to regulate Ca(2+) distribution and the activity of apoptotic proteins in the ER. The apoptotic means of the mitochondria and ER will eventually come together to control the dismantling of the cell by the caspases and other enzymes.
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Affiliation(s)
- Ludivine Walter
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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94
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Osibow K, Malli R, Kostner GM, Graier WF. A new type of non-Ca2+-buffering Apo(a)-based fluorescent indicator for intraluminal Ca2+ in the endoplasmic reticulum. J Biol Chem 2006; 281:5017-5025. [PMID: 16368693 PMCID: PMC4845882 DOI: 10.1074/jbc.m508583200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Genetically encoded Ca2+ indicators are outstanding tools for the assessment of intracellular/organelle Ca2+ dynamics. Basically, most indicators contain the Ca2+-binding site of a (mutated) cytosolic protein that interacts with its natural (mutated) interaction partner upon binding of Ca2+. Consequently, a change in the structure of the sensor occurs that, in turn, alters the fluorescent properties of the sensor. Herein, we present a new type of genetically encoded Ca2+ indicator for the endoplasmic reticulum (ER) (apoK1-er (W. F. Graier, K. Osibow, R. Malli, and G. M. Kostner, patent application number 05450006.1 at the European patent office)) that is based on a single kringle domain from apolipoprotein(a), which is flanked by yellow and cyan fluorescent protein at the 3'- and 5'-ends, respectively. Notably, apoK1-er does not interact with Ca2+ itself but serves as a substrate for calreticulin, the main constitutive Ca2+-binding protein in the ER. ApoK1-er assembles with calreticulin and the protein disulfide isomerase ERp57 and undergoes a conformational shift in a Ca2+-dependent manner that allows fluorescence resonance energy transfer between the two fluorophores. This construct primarily offers three major advantages compared with the already existing probes: (i) it resolves perfectly the physiological range of the free Ca2+ concentration in the ER, (ii) expression of apoK1-er does not affect the Ca2+ buffering capacity of the ER, and (iii) apoK1-er is not inactivated by binding of constitutive interaction partners that prevent Ca2+-dependent conformational changes. These unique characteristics of apoK1-er make this sensor particularly attractive for studies on ER Ca2+ signaling and dynamics in which alteration of Ca2+ fluctuations by expression of any additional Ca2+ buffer essentially has to be avoided.
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Affiliation(s)
- Karin Osibow
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, 8010 Graz, Austria
| | - Roland Malli
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, 8010 Graz, Austria
| | - Gerhard M. Kostner
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, 8010 Graz, Austria
| | - Wolfgang F. Graier
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, 8010 Graz, Austria
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95
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Ihara Y, Urata Y, Goto S, Kondo T. Role of calreticulin in the sensitivity of myocardiac H9c2 cells to oxidative stress caused by hydrogen peroxide. Am J Physiol Cell Physiol 2006; 290:C208-21. [PMID: 16135540 DOI: 10.1152/ajpcell.00075.2005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Calreticulin (CRT), a Ca2+-binding molecular chaperone in the endoplasmic reticulum, plays a vital role in cardiac physiology and pathology. Oxidative stress is a main cause of myocardiac apoptosis in the ischemic heart, but the function of CRT under oxidative stress is not fully understood. In the present study, the effect of overexpression of CRT on susceptibility to apoptosis under oxidative stress was examined using myocardiac H9c2 cells transfected with the CRT gene. Under oxidative stress due to H2O2, the CRT-overexpressing cells were highly susceptible to apoptosis compared with controls. In the overexpressing cells, the levels of cytoplasmic free Ca2+([Ca2+]i) were significantly increased by H2O2, whereas in controls, only a slight increase was observed. The H2O2-induced apoptosis was enhanced by the increase in [Ca2+]icaused by thapsigargin in control cells but was suppressed by BAPTA-AM, a cell-permeable Ca2+chelator in the CRT-overexpressing cells, indicating the importance of the level of [Ca2+]iin the sensitivity to H2O2-induced apoptosis. Suppression of CRT by the introduction of the antisense cDNA of CRT enhanced cytoprotection against oxidative stress compared with controls. Furthermore, we found that the levels of activity of calpain and caspase-12 were elevated through the regulation of [Ca2+]iin the CRT-overexpressing cells treated with H2O2compared with controls. Thus we conclude that the level of CRT regulates the sensitivity to apoptosis under oxidative stress due to H2O2through a change in Ca2+homeostasis and the regulation of the Ca2+-calpain-caspase-12 pathway in myocardiac cells.
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Affiliation(s)
- Yoshito Ihara
- Dept. of Biochemistry and Molecular Biology in Disease, Atomic Bomb Disease Institute, Nagasaki Univ. Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
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96
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Martin V, Groenendyk J, Steiner SS, Guo L, Dabrowska M, Parker JMR, Müller-Esterl W, Opas M, Michalak M. Identification by Mutational Analysis of Amino Acid Residues Essential in the Chaperone Function of Calreticulin. J Biol Chem 2006; 281:2338-46. [PMID: 16291754 DOI: 10.1074/jbc.m508302200] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calreticulin is a Ca2+ -binding chaperone that resides in the lumen of the endoplasmic reticulum and is involved in the regulation of intracellular Ca2+ homeostasis and in the folding of newly synthesized glycoproteins. In this study, we have used site-specific mutagenesis to map amino acid residues that are critical in calreticulin function. We have focused on two cysteine residues (Cys(88) and Cys(120)), which form a disulfide bridge in the N-terminal domain of calreticulin, on a tryptophan residue located in the carbohydrate binding site (Trp(302)), and on certain residues located at the tip of the "hairpin-like" P-domain of the protein (Glu(238), Glu(239), Asp(241), Glu(243), and Trp(244)). Calreticulin mutants were expressed in crt(-/-) fibroblasts, and bradykinin-dependent Ca2+ release was measured as a marker of calreticulin function. Bradykinin-dependent Ca2+ release from the endoplasmic reticulum was rescued by wild-type calreticulin and by the Glu(238), Glu(239), Asp(241), and Glu(243) mutants. The Cys(88) and Cys(120) mutants rescued the calreticulin-deficient phenotype only partially ( approximately 40%), and the Trp(244) and Trp(302) mutants did not rescue it at all. We identified four amino acid residues (Glu(239), Asp(241), Glu(243), and Trp(244)) at the hairpin tip of the P-domain that are critical in the formation of a complex between ERp57 and calreticulin. Although the Glu(239), Asp(241), and Glu(243) mutants did not bind ERp57 efficiently, they fully restored bradykinin-dependent Ca2+ release in crt(-/-) cells. This indicates that binding of ERp57 to calreticulin may not be critical for the chaperone function of calreticulin with respect to the bradykinin receptor.
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Affiliation(s)
- Virginie Martin
- Membrane Protein Research Group and the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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97
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Hu Q, Chang J, Tao L, Yan G, Xie M, Wang Z. Endoplasmic Reticulum Mediated Necrosis-like Apoptosis of HeLa Cells Induced by Ca2+ Oscillation. BMB Rep 2005; 38:709-16. [PMID: 16336787 DOI: 10.5483/bmbrep.2005.38.6.709] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Apoptosis and necrosis are distinguished by modality primarily. Here we show an apoptosis occurred instantly, induced by 300 muM W-7 ((N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride), inhibitor of calmodulin), which demonstrated necrotic modality. As early as 30 min after W-7 addition, apoptotic (sub-diploid) peak could be detected by fluorescence-activated cell sorter (FACS), "DNA ladders" began to emerge also at this time point, activity of caspase-3 elevated obviously within this period. Absence of mitochondrial membrane potential (MMP) reduction and cytochrome c, AIF (apoptosis inducing factor) release, verified that this rapid apoptosis did not proceed through mitochondria pathway. Activation of caspase-12 and changes of other endoplasmic reticulum (ER) located proteins ascertained that ER pathway mediated this necrosis-like apoptosis. Our findings suggest that it is not credible to judge apoptosis by modality. Elucidation of ER pathway is helpful to comprehend the pathology of diseases associated with ER stress, and may offer a new approach to the therapy of cancer and neurodegenerative diseases.
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Affiliation(s)
- Qingliu Hu
- Medical School, Tsinghua University, Beijing 100084, People's Republic of China
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98
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Zhang L, Lookene A, Wu G, Olivecrona G. Calcium triggers folding of lipoprotein lipase into active dimers. J Biol Chem 2005; 280:42580-91. [PMID: 16179346 DOI: 10.1074/jbc.m507252200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The active form of lipoprotein lipase (LPL) is a noncovalent homodimer of 55-kDa subunits. The dimer is unstable and tends to undergo irreversible dissociation into inactive monomers. We noted that a preparation of such monomers slowly regained traces of activity under assay conditions with substrate, heparin, and serum or in cell culture medium containing serum. We therefore studied the refolding pathway of LPL after full denaturation in 6 M guanidinium chloride or after dissociation into monomers in 1 M guanidinium chloride. In crude systems, we identified serum as the factor promoting reactivation. Further investigations demonstrated that Ca2+ was the crucial component in serum for reactivation of LPL and that refolding involved at least two steps. Studies of far-UV circular dichroism, fluorescence, and proteolytic cleavage patterns showed that LPL started to refold from the C-terminal domain, independent of calcium. The first step was rapid and resulted in formation of an inactive monomer with a completely folded C-terminal domain, whereas the N-terminal domain was in the molten globule state. The second step was promoted by Ca2+ and converted LPL monomers from the molten globule state to dimerization-competent and more tightly folded monomers that rapidly formed active LPL dimers. The second step was slow, and it appears that proline isomerization (rather than dimerization as such) is rate-limiting. Inactive monomers isolated from human tissue recovered activity under the influence of Ca2+. We speculate that Ca2+-dependent control of LPL dimerization might be involved in the normal post-translational regulation of LPL activity.
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Affiliation(s)
- Liyan Zhang
- Department of Medical Biosciences, Physiological Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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99
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Lynch J, Guo L, Gelebart P, Chilibeck K, Xu J, Molkentin JD, Agellon LB, Michalak M. Calreticulin signals upstream of calcineurin and MEF2C in a critical Ca(2+)-dependent signaling cascade. ACTA ACUST UNITED AC 2005; 170:37-47. [PMID: 15998798 PMCID: PMC2171392 DOI: 10.1083/jcb.200412156] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We uncovered a new pathway of interplay between calreticulin and myocyte-enhancer factor (MEF) 2C, a cardiac-specific transcription factor. We establish that calreticulin works upstream of calcineurin and MEF2C in a Ca2+-dependent signal transduction cascade that links the endoplasmic reticulum and the nucleus during cardiac development. In the absence of calreticulin, translocation of MEF2C to the nucleus is compromised. This defect is reversed by calreticulin itself or by a constitutively active form of calcineurin. Furthermore, we show that expression of the calreticulin gene itself is regulated by MEF2C in vitro and in vivo and that, in turn, increased expression of calreticulin affects MEF2C transcriptional activity. The present findings provide a clear molecular explanation for the embryonic lethality observed in calreticulin-deficient mice and emphasize the importance of calreticulin in the early stages of cardiac development. Our study illustrates the existence of a positive feedback mechanism that ensures an adequate supply of releasable Ca2+ is maintained within the cell for activation of calcineurin and, subsequently, for proper functioning of MEF2C.
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Affiliation(s)
- Jeffrey Lynch
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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100
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Wilczynska Z, Happle K, Müller-Taubenberger A, Schlatterer C, Malchow D, Fisher PR. Release of Ca2+ from the endoplasmic reticulum contributes to Ca2+ signaling in Dictyostelium discoideum. EUKARYOTIC CELL 2005; 4:1513-25. [PMID: 16151245 PMCID: PMC1214202 DOI: 10.1128/ec.4.9.1513-1525.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 06/17/2005] [Indexed: 11/20/2022]
Abstract
Ca2+ responses to two chemoattractants, folate and cyclic AMP (cAMP), were assayed in Dictyostelium D. discoideum mutants deficient in one or both of two abundant Ca2+-binding proteins of the endoplasmic reticulum (ER), calreticulin and calnexin. Mutants deficient in either or both proteins exhibited enhanced cytosolic Ca2+ responses to both attractants. Not only were the mutant responses greater in amplitude, but they also exhibited earlier onsets, faster rise rates, earlier peaks, and faster fall rates. Correlations among these kinetic parameters and the response amplitudes suggested that key events in the Ca2+ response are autoregulated by the magnitude of the response itself, i.e., by cytosolic Ca2+ levels. This autoregulation was sufficient to explain the altered kinetics of the mutant responses: larger responses are faster in both mutant and wild-type cells in response to both folate (vegetative cells) and cAMP (differentiated cells). Searches of the predicted D. discoideum proteome revealed three putative Ca2+ pumps and four putative Ca2+ channels. All but one contained sequence motifs for Ca2+- or calmodulin-binding sites, consistent with Ca2+ signals being autoregulatory. Although cytosolic Ca2+ responses in the calnexin and calreticulin mutants are enhanced, the influx of Ca2+ from the extracellular medium into the mutant cells was smaller. Compared to wild-type cells, Ca2+ release from the ER in the mutants thus contributes more to the total cytosolic Ca2+ response while influx from the extracellular medium contributes less. These results provide the first molecular genetic evidence that release of Ca2+ from the ER contributes to cytosolic Ca2+ responses in D. discoideum.
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Affiliation(s)
- Zofia Wilczynska
- Department of Microbiology, La Trobe University, Victoria 3086, Australia
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