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Muinos-Bühl A, Rombo R, Janzen E, Ling KK, Hupperich K, Rigo F, Bennett CF, Wirth B. Combinatorial ASO-mediated therapy with low dose SMN and the protective modifier Chp1 is not sufficient to ameliorate SMA pathology hallmarks. Neurobiol Dis 2022; 171:105795. [PMID: 35724821 DOI: 10.1016/j.nbd.2022.105795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/17/2022] [Accepted: 06/14/2022] [Indexed: 10/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating genetically inherited neuromuscular disorder characterized by the progressive loss of motor neurons in the spinal cord, leading to muscle atrophy and weakness. Although SMA is caused by homozygous mutations in SMN1, the disease severity is mainly determined by the copy number of SMN2, an almost identical gene that produces ~10% correctly spliced SMN transcripts. Recently, three FDA- and EMA-approved therapies that either increase correctly spliced SMN2 transcripts (nusinersen and risdiplam) or replace SMN1 (onasemnogen abeparvovec-xioi) have revolutionized the clinical outcome in SMA patients. However, for severely affected SMA individuals carrying only two SMN2 copies even a presymptomatic therapy might be insufficient to fully counteract disease development. Therefore, SMN-independent compounds supporting SMN-dependent therapies represent a promising therapeutic approach. Recently, we have shown a significant amelioration of SMA disease hallmarks in a severely affected SMA mouse carrying a mutant Chp1 allele when combined with low-dose of SMN antisense oligonucleotide (ASO) treatment. CHP1 is a direct interacting partner of PLS3, a strong protective modifier of SMA. Both proteins ameliorate impaired endocytosis in SMA and significantly restore pathological hallmarks in mice. Here, we aimed to pharmacologically reduce CHP1 levels in an ASO-based combinatorial therapy targeting SMN and Chp1. Chp1 modulation is a major challenge since its genetic reduction to ~50% has shown to ameliorate SMA pathology, while the downregulation below that level causes cerebellar ataxia. Efficacy and tolerability studies determined that a single injection of 30 μg Chp1-ASO4 in the CNS is a safe dosage that significantly reduced CHP1 levels to ~50% at postnatal day (PND)14. Unfortunately, neither electrophysiological predictors such as compound muscle action potential (CMAP) or motor unit number estimation (MUNE) nor histological hallmarks of SMA in neuromuscular junction (NMJ), spinal cord or muscle were ameliorated in SMA mice treated with Chp1-ASO4 compared to CTRL-ASO at PND21. Surprisingly, CHP1 levels were almost at control level 4-weeks post injection, indicating a rather short-term effect of the ASO. Therefore, we re-administrated Chp1-ASO4 by i.c.v. bolus injection at PND28. However, no significant improvement of SMA hallmarks were seen at 2 month-of-age either. In conclusion, in contrast to the protective effect of genetically-induced Chp1 reduction on SMA, combinatorial therapy with Chp1- and SMN-ASOs failed to significantly ameliorate the SMA pathology. Chp1-ASOs compared to SMN-ASO proved to have rather short-term effect and even reinjection had no significant impact on SMA progression, suggesting that further optimization of the ASO may be required to fully explore the combination.
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Affiliation(s)
- A Muinos-Bühl
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
| | - R Rombo
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
| | - E Janzen
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - K K Ling
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA.
| | - K Hupperich
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - F Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA.
| | - C F Bennett
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA.
| | - B Wirth
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50674 Cologne, Germany; Center for Rare Diseases, University Hospital of Cologne, 50931 Cologne, Germany.
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Decoding the Phosphatase Code: Regulation of Cell Proliferation by Calcineurin. Int J Mol Sci 2022; 23:ijms23031122. [PMID: 35163061 PMCID: PMC8835043 DOI: 10.3390/ijms23031122] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/18/2022] [Accepted: 01/18/2022] [Indexed: 02/06/2023] Open
Abstract
Calcineurin, a calcium-dependent serine/threonine phosphatase, integrates the alterations in intracellular calcium levels into downstream signaling pathways by regulating the phosphorylation states of several targets. Intracellular Ca2+ is essential for normal cellular physiology and cell cycle progression at certain critical stages of the cell cycle. Recently, it was reported that calcineurin is activated in a variety of cancers. Given that abnormalities in calcineurin signaling can lead to malignant growth and cancer, the calcineurin signaling pathway could be a potential target for cancer treatment. For example, NFAT, a typical substrate of calcineurin, activates the genes that promote cell proliferation. Furthermore, cyclin D1 and estrogen receptors are dephosphorylated and stabilized by calcineurin, leading to cell proliferation. In this review, we focus on the cell proliferative functions and regulatory mechanisms of calcineurin and summarize the various substrates of calcineurin. We also describe recent advances regarding dysregulation of the calcineurin activity in cancer cells. We hope that this review will provide new insights into the potential role of calcineurin in cancer development.
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Reyes-García SE, Escobar ML. Calcineurin Participation in Hebbian and Homeostatic Plasticity Associated With Extinction. Front Cell Neurosci 2021; 15:685838. [PMID: 34220454 PMCID: PMC8242195 DOI: 10.3389/fncel.2021.685838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/25/2021] [Indexed: 12/21/2022] Open
Abstract
In nature, animals need to adapt to constant changes in their environment. Learning and memory are cognitive capabilities that allow this to happen. Extinction, the reduction of a certain behavior or learning previously established, refers to a very particular and interesting type of learning that has been the basis of a series of therapies to diminish non-adaptive behaviors. In recent years, the exploration of the cellular and molecular mechanisms underlying this type of learning has received increasing attention. Hebbian plasticity (the activity-dependent modification of the strength or efficacy of synaptic transmission), and homeostatic plasticity (the homeostatic regulation of plasticity) constitute processes intimately associated with memory formation and maintenance. Particularly, long-term depression (LTD) has been proposed as the underlying mechanism of extinction, while the protein phosphatase calcineurin (CaN) has been widely related to both the extinction process and LTD. In this review, we focus on the available evidence that sustains CaN modulation of LTD and its association with extinction. Beyond the classic view, we also examine the interconnection among extinction, Hebbian and homeostatic plasticity, as well as emergent evidence of the participation of kinases and long-term potentiation (LTP) on extinction learning, highlighting the importance of the balance between kinases and phosphatases in the expression of extinction. Finally, we also integrate data that shows the association between extinction and less-studied phenomena, such as synaptic silencing and engram formation that open new perspectives in the field.
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Affiliation(s)
- Salma E Reyes-García
- Laboratorio de Neurobiología del Aprendizaje y la Memoria, División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Martha L Escobar
- Laboratorio de Neurobiología del Aprendizaje y la Memoria, División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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4
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Cottle WT, Wallert CH, Anderson KK, Tran MF, Bakker CL, Wallert MA, Provost JJ. Calcineurin homologous protein isoform 2 supports tumor survival via the sodium hydrogen exchanger isoform 1 in non-small cell lung cancer. Tumour Biol 2020; 42:1010428320937863. [PMID: 32686600 DOI: 10.1177/1010428320937863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Maintaining intracellular pH is crucial for preserving healthy cellular behavior and, when dysregulated, results in increased proliferation, migration, and invasion. The Na+/H+ exchanger isoform 1 is a highly regulated transmembrane antiporter that maintains pH homeostasis by exporting protons in response to intra- and extracellular signals. Activation of Na+/H+ exchanger isoform 1 is exquisitely regulated by the extracellular environment and protein cofactors, including calcineurin B homologous proteins 1 and 2. While Na+/H+ exchanger isoform 1 and calcineurin B homologous protein 1 are ubiquitously expressed, calcineurin B homologous protein 2 shows tissue-specific expression and upregulation in a variety of cancer cells. In addition, calcineurin B homologous protein 2 expression is modulated by tumorigenic extracellular conditions like low nutrients. To understand the role of calcineurin B homologous protein 2 in tumorigenesis and survival in lung cancer, we surveyed existing databases and formed a comprehensive report of Na+/H+ exchanger isoform 1, calcineurin B homologous protein 1, and calcineurin B homologous protein 2 expression in diseased and non-diseased tissues. We show that calcineurin B homologous protein 2 is upregulated during oncogenesis in many adeno and squamous carcinomas. To understand the functional role of calcineurin B homologous protein 2 upregulation, we evaluated the effect of Na+/H+ exchanger isoform 1 and calcineurin B homologous protein 2 depletion on cellular function during cancer progression in situ. Here, we show that calcineurin B homologous protein 2 functions through Na+/H+ exchanger isoform 1 to effect cell proliferation, cell migration, steady-state pHi, and anchorage-independent tumor growth. Finally, we present evidence that calcineurin B homologous protein 2 depletion in vivo has potential to reduce tumor burden in a xenograft model. Together, these data support the tumor-promoting potential of aberrant calcineurin B homologous protein 2 expression and position calcineurin B homologous protein 2 as a potential therapeutic target for the treatment of non-small cell lung cancer.
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Affiliation(s)
- Wayne Taylor Cottle
- Department of Chemistry and Biochemistry, University of San Diego, San Diego, CA, USA
| | | | - Kristine Kay Anderson
- Department of Chemistry and Biochemistry, University of San Diego, San Diego, CA, USA
| | - Michelle Fang Tran
- Department of Chemistry and Biochemistry, University of San Diego, San Diego, CA, USA
| | - Clare Loraine Bakker
- Department of Chemistry and Biochemistry, University of San Diego, San Diego, CA, USA
| | | | - Joseph John Provost
- Department of Chemistry and Biochemistry, University of San Diego, San Diego, CA, USA
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5
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Benoist L, Corre E, Bernay B, Henry J, Zatylny-Gaudin C. -Omic Analysis of the Sepia officinalis White Body: New Insights into Multifunctionality and Haematopoiesis Regulation. J Proteome Res 2020; 19:3072-3087. [PMID: 32643382 DOI: 10.1021/acs.jproteome.0c00100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cephalopods, like other protostomes, lack an adaptive immune system and only rely on an innate immune system. The main immune cells are haemocytes (Hcts), which are able to respond to pathogens and external attacks. First reports based on morphological observations revealed that the white body (WB) located in the optic sinuses of cuttlefish was the origin of Hcts. Combining transcriptomic and proteomic analyses, we identified several factors known to be involved in haematopoiesis in vertebrate species in cuttlefish WB. Among these factors, members of the JAK-STAT signaling pathway were identified, some of them for the first time in a molluscan transcriptome and proteome. Immune factors, such as members of the Toll/NF-κB signaling pathway, pattern recognition proteins and receptors, and members of the oxidative stress responses, were also identified, and support an immune role of the WB. Both transcriptome and proteome analyses revealed that the WB harbors an intense metabolism concurrent with the haematopoietic function. Finally, a comparative analysis of the WB and Hct proteomes revealed many proteins in common, confirming previous morphological studies on the origin of Hcts in cuttlefish. This molecular work demonstrates that the WB is multifunctional and provides bases for haematopoiesis regulation in cuttlefish.
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Affiliation(s)
- Louis Benoist
- NORMANDIE UNIV, UNICAEN, CNRS, BOREA, 14000 Caen, France.,Laboratoire de Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen-Normandie, MNHN, SU, UA, CNRS, IRD, Esplanade de la paix, 14032 Caen Cedex, France
| | - Erwan Corre
- Plateforme ABiMS, Station Biologique de Roscoff (CNRS-Sorbonne Université), 29688 Roscoff, France
| | - Benoit Bernay
- Plateforme PROTEOGEN, SF 4206 ICORE, Normandie université, Esplanade de la Paix, 14032 Caen Cedex, France
| | - Joel Henry
- NORMANDIE UNIV, UNICAEN, CNRS, BOREA, 14000 Caen, France.,Laboratoire de Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen-Normandie, MNHN, SU, UA, CNRS, IRD, Esplanade de la paix, 14032 Caen Cedex, France
| | - Céline Zatylny-Gaudin
- NORMANDIE UNIV, UNICAEN, CNRS, BOREA, 14000 Caen, France.,Laboratoire de Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen-Normandie, MNHN, SU, UA, CNRS, IRD, Esplanade de la paix, 14032 Caen Cedex, France
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6
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Janzen E, Mendoza-Ferreira N, Hosseinibarkooie S, Schneider S, Hupperich K, Tschanz T, Grysko V, Riessland M, Hammerschmidt M, Rigo F, Bennett CF, Kye MJ, Torres-Benito L, Wirth B. CHP1 reduction ameliorates spinal muscular atrophy pathology by restoring calcineurin activity and endocytosis. Brain 2019; 141:2343-2361. [PMID: 29961886 PMCID: PMC6061875 DOI: 10.1093/brain/awy167] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 04/26/2018] [Indexed: 12/12/2022] Open
Abstract
Autosomal recessive spinal muscular atrophy (SMA), the leading genetic cause of infant lethality, is caused by homozygous loss of the survival motor neuron 1 (SMN1) gene. SMA disease severity inversely correlates with the number of SMN2 copies, which in contrast to SMN1, mainly produce aberrantly spliced transcripts. Recently, the first SMA therapy based on antisense oligonucleotides correcting SMN2 splicing, namely SPINRAZATM, has been approved. Nevertheless, in type I SMA-affected individuals—representing 60% of SMA patients—the elevated SMN level may still be insufficient to restore motor neuron function lifelong. Plastin 3 (PLS3) and neurocalcin delta (NCALD) are two SMN-independent protective modifiers identified in humans and proved to be effective across various SMA animal models. Both PLS3 overexpression and NCALD downregulation protect against SMA by restoring impaired endocytosis; however, the exact mechanism of this protection is largely unknown. Here, we identified calcineurin-like EF-hand protein 1 (CHP1) as a novel PLS3 interacting protein using a yeast-two-hybrid screen. Co-immunoprecipitation and pull-down assays confirmed a direct interaction between CHP1 and PLS3. Although CHP1 is ubiquitously present, it is particularly abundant in the central nervous system and at SMA-relevant sites including motor neuron growth cones and neuromuscular junctions. Strikingly, we found elevated CHP1 levels in SMA mice. Congruently, CHP1 downregulation restored impaired axonal growth in Smn-depleted NSC34 motor neuron-like cells, SMA zebrafish and primary murine SMA motor neurons. Most importantly, subcutaneous injection of low-dose SMN antisense oligonucleotide in pre-symptomatic mice doubled the survival rate of severely-affected SMA mice, while additional CHP1 reduction by genetic modification prolonged survival further by 1.6-fold. Moreover, CHP1 reduction further ameliorated SMA disease hallmarks including electrophysiological defects, smaller neuromuscular junction size, impaired maturity of neuromuscular junctions and smaller muscle fibre size compared to low-dose SMN antisense oligonucleotide alone. In NSC34 cells, Chp1 knockdown tripled macropinocytosis whereas clathrin-mediated endocytosis remained unaffected. Importantly, Chp1 knockdown restored macropinocytosis in Smn-depleted cells by elevating calcineurin phosphatase activity. CHP1 is an inhibitor of calcineurin, which collectively dephosphorylates proteins involved in endocytosis, and is therefore crucial in synaptic vesicle endocytosis. Indeed, we found marked hyperphosphorylation of dynamin 1 in SMA motor neurons, which was restored to control level by the heterozygous Chp1 mutant allele. Taken together, we show that CHP1 is a novel SMA modifier that directly interacts with PLS3, and that CHP1 reduction ameliorates SMA pathology by counteracting impaired endocytosis. Most importantly, we demonstrate that CHP1 reduction is a promising SMN-independent therapeutic target for a combinatorial SMA therapy.
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Affiliation(s)
- Eva Janzen
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Natalia Mendoza-Ferreira
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Seyyedmohsen Hosseinibarkooie
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Svenja Schneider
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Kristina Hupperich
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Theresa Tschanz
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Vanessa Grysko
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Markus Riessland
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany.,Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, USA
| | - Matthias Hammerschmidt
- Institute for Zoology, Developmental Biology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | | | | | - Min Jeong Kye
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Laura Torres-Benito
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Rare Diseases Cologne, University Hospital of Cologne, Cologne, Germany
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7
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Bowlt Blacklock KL, Birand Z, Selmic LE, Nelissen P, Murphy S, Blackwood L, Bass J, McKay J, Fox R, Beaver S, Starkey M. Genome-wide analysis of canine oral malignant melanoma metastasis-associated gene expression. Sci Rep 2019; 9:6511. [PMID: 31019223 PMCID: PMC6482147 DOI: 10.1038/s41598-019-42839-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 04/04/2019] [Indexed: 12/12/2022] Open
Abstract
Oral malignant melanoma (OMM) is the most common canine melanocytic neoplasm. Overlap between the somatic mutation profiles of canine OMM and human mucosal melanomas suggest a shared UV-independent molecular aetiology. In common with human mucosal melanomas, most canine OMM metastasise. There is no reliable means of predicting canine OMM metastasis, and systemic therapies for metastatic disease are largely palliative. Herein, we employed exon microarrays for comparative expression profiling of FFPE biopsies of 18 primary canine OMM that metastasised and 10 primary OMM that did not metastasise. Genes displaying metastasis-associated expression may be targets for anti-metastasis treatments, and biomarkers of OMM metastasis. Reduced expression of CXCL12 in the metastasising OMMs implies that the CXCR4/CXCL12 axis may be involved in OMM metastasis. Increased expression of APOBEC3A in the metastasising OMMs may indicate APOBEC3A-induced double-strand DNA breaks and pro-metastatic hypermutation. DNA double strand breakage triggers the DNA damage response network and two Fanconi anaemia DNA repair pathway members showed elevated expression in the metastasising OMMs. Cross-validation was employed to test a Linear Discriminant Analysis classifier based upon the RT-qPCR-measured expression levels of CXCL12, APOBEC3A and RPL29. Classification accuracies of 94% (metastasising OMMs) and 86% (non-metastasising OMMs) were estimated.
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Affiliation(s)
| | - Z Birand
- Animal Health Trust, Newmarket, Suffolk, UK
| | - L E Selmic
- Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA
| | - P Nelissen
- Dick White Referrals, Newmarket, Suffolk, UK
| | - S Murphy
- Animal Health Trust, Newmarket, Suffolk, UK
- The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - L Blackwood
- Institute of Veterinary Science, University of Liverpool, Liverpool, UK
| | - J Bass
- Animal Health Trust, Newmarket, Suffolk, UK
- Finn Pathologists, Harleston, UK
| | - J McKay
- IDEXX Laboratories, Ltd, Wetherby, UK
| | - R Fox
- Finn Pathologists, Harleston, UK
| | - S Beaver
- Nationwide Laboratory Services, Poulton-le-Fylde, UK
| | - M Starkey
- Animal Health Trust, Newmarket, Suffolk, UK.
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8
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Tarasova EO, Gaydukov AE, Balezina OP. Calcineurin and Its Role in Synaptic Transmission. BIOCHEMISTRY (MOSCOW) 2018; 83:674-689. [PMID: 30195324 DOI: 10.1134/s0006297918060056] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Calcineurin (CaN) is a serine/threonine phosphatase widely expressed in different cell types and structures including neurons and synapses. The most studied role of CaN is its involvement in the functioning of postsynaptic structures of central synapses. The role of CaN in the presynaptic structures of central and peripheral synapses is less understood, although it has generated a considerable interest and is a subject of a growing number of studies. The regulatory role of CaN in synaptic vesicle endocytosis in the synapse terminals is actively studied. In recent years, new targets of CaN have been identified and its role in the regulation of enzymes and neurotransmitter secretion in peripheral neuromuscular junctions has been revealed. CaN is the only phosphatase that requires calcium and calmodulin for activation. In this review, we present details of CaN molecular structure and give a detailed description of possible mechanisms of CaN activation involving calcium, enzymes, and endogenous and exogenous inhibitors. Known and newly discovered CaN targets at pre- and postsynaptic levels are described. CaN activity in synaptic structures is discussed in terms of functional involvement of this phosphatase in synaptic transmission and neurotransmitter release.
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Affiliation(s)
- E O Tarasova
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
| | - A E Gaydukov
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia. .,Pirogov Russian National Research Medical University, Moscow, 117997, Russia
| | - O P Balezina
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119991, Russia
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Abstract
Mitochondria are the cell's power plant that must be in a proper functional state in order to produce the energy necessary for basic cellular functions, such as proliferation. Mitochondria are 'dynamic' in that they are constantly undergoing fission and fusion to remain in a functional state throughout the cell cycle, as well as during other vital processes such as energy supply, cellular respiration and programmed cell death. The mitochondrial fission/fusion machinery is involved in generating young mitochondria, while eliminating old, damaged and non-repairable ones. As a result, the organelles change in shape, size and number throughout the cell cycle. Such precise and accurate balance is maintained by the cytoskeletal transporting system via microtubules, which deliver the mitochondrion from one location to another. During the gap phases G1 and G2, mitochondria form an interconnected network, whereas in mitosis and S-phase fragmentation of the mitochondrial network will take place. However, such balance is lost during neoplastic transformation and autoimmune disorders. Several proteins, such as Drp1, Fis1, Kif-family proteins, Opa1, Bax and mitofusins change in activity and might link the mitochondrial fission/fusion events with processes such as alteration of mitochondrial membrane potential, apoptosis, necrosis, cell cycle arrest, and malignant growth. All this indicates how vital proper functioning of mitochondria is in maintaining cell integrity and preventing carcinogenesis.
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Affiliation(s)
- Rostyslav Horbay
- Terrence Donnelly Center for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, Canada.
| | - Rostyslav Bilyy
- Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
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10
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A proteomic characterization shows differences in the milk fat globule membrane of buffalo and bovine milk. FOOD BIOSCI 2017. [DOI: 10.1016/j.fbio.2017.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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11
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Transcriptional dysregulation of Interferome in experimental and human Multiple Sclerosis. Sci Rep 2017; 7:8981. [PMID: 28827704 PMCID: PMC5566335 DOI: 10.1038/s41598-017-09286-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/18/2017] [Indexed: 11/10/2022] Open
Abstract
Recent evidence indicates that single multiple sclerosis (MS) susceptibility genes involved in interferon (IFN) signaling display altered transcript levels in peripheral blood of untreated MS subjects, suggesting that responsiveness to endogenous IFN is dysregulated during neuroinflammation. To prove this hypothesis we exploited the systematic collection of IFN regulated genes (IRG) provided by the Interferome database and mapped Interferome changes in experimental and human MS. Indeed, central nervous system tissue and encephalitogenic CD4 T cells during experimental autoimmune encephalomyelitis were characterized by massive changes in Interferome transcription. Further, the analysis of almost 500 human blood transcriptomes showed that (i) several IRG changed expression at distinct MS stages with a core of 21 transcripts concordantly dysregulated in all MS forms compared with healthy subjects; (ii) 100 differentially expressed IRG were validated in independent case-control cohorts; and (iii) 53 out of 100 dysregulated IRG were targeted by IFN-beta treatment in vivo. Finally, ex vivo and in vitro experiments established that IFN-beta administration modulated expression of two IRG, ARRB1 and CHP1, in immune cells. Our study confirms the impairment of Interferome in experimental and human MS, and describes IRG signatures at distinct disease stages which can represent novel therapeutic targets in MS.
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12
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Wang YL, Zhang CX. Putting a brake on synaptic vesicle endocytosis. Cell Mol Life Sci 2017; 74:2917-2927. [PMID: 28361181 PMCID: PMC11107501 DOI: 10.1007/s00018-017-2506-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 02/14/2017] [Accepted: 03/14/2017] [Indexed: 01/16/2023]
Abstract
In chemical synapses, action potentials evoke synaptic vesicle fusion with the presynaptic membrane at the active zone to release neurotransmitter. Synaptic vesicle endocytosis (SVE) then follows exocytosis to recapture vesicle proteins and lipid components for recycling and the maintenance of membrane homeostasis. Therefore, SVE plays an essential role during neurotransmission and is one of the most precisely regulated biological processes. Four modes of SVE have been characterized and both positive and negative regulators have been identified. However, our understanding of SVE regulation remains unclear, especially the identity of negative regulators and their mechanisms of action. Here, we review the current knowledge of proteins that function as inhibitors of SVE and their modes of action in different forms of endocytosis. We also propose possible physiological roles of such negative regulation. We believe that a better understanding of SVE regulation, especially the inhibitory mechanisms, will shed light on neurotransmission in health and disease.
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Affiliation(s)
- Ya-Long Wang
- Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Beijing, China
| | - Claire Xi Zhang
- Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Beijing, China.
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Parra V, Rothermel BA. Calcineurin signaling in the heart: The importance of time and place. J Mol Cell Cardiol 2017; 103:121-136. [PMID: 28007541 PMCID: PMC5778886 DOI: 10.1016/j.yjmcc.2016.12.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/12/2016] [Accepted: 12/16/2016] [Indexed: 12/20/2022]
Abstract
The calcium-activated protein phosphatase, calcineurin, lies at the intersection of protein phosphorylation and calcium signaling cascades, where it provides an essential nodal point for coordination between these two fundamental modes of intracellular communication. In excitatory cells, such as neurons and cardiomyocytes, that experience rapid and frequent changes in cytoplasmic calcium, calcineurin protein levels are exceptionally high, suggesting that these cells require high levels of calcineurin activity. Yet, it is widely recognized that excessive activation of calcineurin in the heart contributes to pathological hypertrophic remodeling and the progression to failure. How does a calcium activated enzyme function in the calcium-rich environment of the continuously contracting heart without pathological consequences? This review will discuss the wide range of calcineurin substrates relevant to cardiovascular health and the mechanisms calcineurin uses to find and act on appropriate substrates in the appropriate location while potentially avoiding others. Fundamental differences in calcineurin signaling in neonatal verses adult cardiomyocytes will be addressed as well as the importance of maintaining heterogeneity in calcineurin activity across the myocardium. Finally, we will discuss how circadian oscillations in calcineurin activity may facilitate integration with other essential but conflicting processes, allowing a healthy heart to reap the benefits of calcineurin signaling while avoiding the detrimental consequences of sustained calcineurin activity that can culminate in heart failure.
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Affiliation(s)
- Valentina Parra
- Advanced Centre for Chronic Disease (ACCDiS), Facultad Ciencias Quimicas y Farmaceuticas, Universidad de Chile, Santiago,Chile; Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Quimicas y Farmaceuticas, Universidad de Chie, Santiago, Chile
| | - Beverly A Rothermel
- Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Centre, Dallas, TX, USA; Department of Molecular Biology, University of Texas Southwestern Medical Centre, Dallas, TX, USA.
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The Emerging Roles of the Calcineurin-Nuclear Factor of Activated T-Lymphocytes Pathway in Nervous System Functions and Diseases. J Aging Res 2016; 2016:5081021. [PMID: 27597899 PMCID: PMC5002468 DOI: 10.1155/2016/5081021] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/21/2016] [Indexed: 12/27/2022] Open
Abstract
The ongoing epidemics of metabolic diseases and increase in the older population have increased the incidences of neurodegenerative diseases. Evidence from murine and cell line models has implicated calcineurin-nuclear factor of activated T-lymphocytes (NFAT) signaling pathway, a Ca2+/calmodulin-dependent major proinflammatory pathway, in the pathogenesis of these diseases. Neurotoxins such as amyloid-β, tau protein, and α-synuclein trigger abnormal calcineurin/NFAT signaling activities. Additionally increased activities of endogenous regulators of calcineurin like plasma membrane Ca2+-ATPase (PMCA) and regulator of calcineurin 1 (RCAN1) also cause neuronal and glial loss and related functional alterations, in neurodegenerative diseases, psychotic disorders, epilepsy, and traumatic brain and spinal cord injuries. Treatment with calcineurin/NFAT inhibitors induces some degree of neuroprotection and decreased reactive gliosis in the central and peripheral nervous system. In this paper, we summarize and discuss the current understanding of the roles of calcineurin/NFAT signaling in physiology and pathologies of the adult and developing nervous system, with an emphasis on recent reports and cutting-edge findings. Calcineurin/NFAT signaling is known for its critical roles in the developing and adult nervous system. Its role in physiological and pathological processes is still controversial. However, available data suggest that its beneficial and detrimental effects are context-dependent. In view of recent reports calcineurin/NFAT signaling is likely to serve as a potential therapeutic target for neurodegenerative diseases and conditions. This review further highlights the need to characterize better all factors determining the outcome of calcineurin/NFAT signaling in diseases and the downstream targets mediating the beneficial and detrimental effects.
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NHE9 induces chemoradiotherapy resistance in esophageal squamous cell carcinoma by upregulating the Src/Akt/β-catenin pathway and Bcl-2 expression. Oncotarget 2016; 6:12405-20. [PMID: 25915159 PMCID: PMC4494947 DOI: 10.18632/oncotarget.3618] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 03/14/2015] [Indexed: 11/25/2022] Open
Abstract
Recently, we found that NHE9 mRNA was upregulated in chemoradiotherapy (CRT)-resistant esophageal squamous cell carcinoma (ESCC); however, the underlying mechanisms were unclear. Here, we aimed to clarify the functional contribution of NHE9 to CRT resistance, understand the molecular basis of NHE9-dependent resistance in ESCC, and identify potential therapeutic targets. Our results showed that NHE9 prevented CRT-induced apoptosis. Importantly, we found that RACK1 is a novel binding partner of NHE9 and that NHE9-dependent induction of CRT resistance requires the activation of RACK1-associated Src/Akt/β-catenin signaling. Moreover, upregulated Bcl-2 protein was also observed in cells exhibiting NHE9-induced CRT resistance. A higher NHE9 level was associated with a poor response to CRT and less decrease in T and N stage in ESCC patients. Furthermore, combining either Dasatinib or ABT-737 with CRT significantly reduced tumor volume, and the response to CRT was restored when these inhibitors were used together with CRT in a xenograft nude mouse model with NHE9 overexpression. Taken together, our findings demonstrate that NHE9 can be an effective predictor of CRT response and may be useful in the development of targeted therapies for CRT-resistant ESCC.
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Allman E, Wang Q, Walker RL, Austen M, Peters MA, Nehrke K. Calcineurin homologous proteins regulate the membrane localization and activity of sodium/proton exchangers in C. elegans. Am J Physiol Cell Physiol 2015; 310:C233-42. [PMID: 26561640 DOI: 10.1152/ajpcell.00291.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/09/2015] [Indexed: 11/22/2022]
Abstract
Calcineurin B homologous proteins (CHP) are N-myristoylated, EF-hand Ca(2+)-binding proteins that bind to and regulate Na(+)/H(+) exchangers, which occurs through a variety of mechanisms whose relative significance is incompletely understood. Like mammals, Caenorhabditis elegans has three CHP paralogs, but unlike mammals, worms can survive CHP loss-of-function. However, mutants for the CHP ortholog PBO-1 are unfit, and PBO-1 has been shown to be required for proton signaling by the basolateral Na(+)/H(+) exchanger NHX-7 and for proton-coupled intestinal nutrient uptake by the apical Na(+)/H(+) exchanger NHX-2. Here, we have used this genetic model organism to interrogate PBO-1's mechanism of action. Using fluorescent tags to monitor Na(+)/H(+) exchanger trafficking and localization, we found that loss of either PBO-1 binding or activity caused NHX-7 to accumulate in late endosomes/lysosomes. In contrast, NHX-2 was stabilized at the apical membrane by a nonfunctional PBO-1 protein and was only internalized following its complete loss. Additionally, two pbo-1 paralogs were identified, and their expression patterns were analyzed. One of these contributed to the function of the excretory cell, which acts like a kidney in worms, establishing an alternative model for testing the role of this protein in membrane transporter trafficking and regulation. These results lead us to conclude that the role of CHP in Na(+)/H(+) exchanger regulation differs between apical and basolateral transporters. This further emphasizes the importance of proper targeting of Na(+)/H(+) exchangers and the critical role of CHP family proteins in this process.
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Affiliation(s)
- Erik Allman
- Departments of Pharmacology and Physiology and Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York; Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania
| | - Qian Wang
- Departments of Pharmacology and Physiology and Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Rachel L Walker
- Departments of Pharmacology and Physiology and Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Molly Austen
- Departments of Pharmacology and Physiology and Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | | | - Keith Nehrke
- Departments of Pharmacology and Physiology and Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York;
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Du J, Hincke MT, Rose-Martel M, Hennequet-Antier C, Brionne A, Cogburn LA, Nys Y, Gautron J. Identifying specific proteins involved in eggshell membrane formation using gene expression analysis and bioinformatics. BMC Genomics 2015; 16:792. [PMID: 26470705 PMCID: PMC4608100 DOI: 10.1186/s12864-015-2013-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/04/2015] [Indexed: 12/16/2022] Open
Abstract
Background The avian eggshell membranes surround the egg white and provide a structural foundation for calcification of the eggshell which is essential for avian reproduction; moreover, it is also a natural biomaterial with many potential industrial and biomedical applications. Due to the insoluble and stable nature of the eggshell membrane fibres, their formation and protein constituents remain poorly characterized. The purpose of this study was to identify genes encoding eggshell membrane proteins, particularly those responsible for its structural features, by analyzing the transcriptome of the white isthmus segment of the oviduct, which is the specialized region responsible for the fabrication of the membrane fibres. Results The Del-Mar 14 K chicken microarray was used to investigate up-regulated expression of transcripts in the white isthmus (WI) compared with the adjacent magnum (Ma) and uterine (Ut) segments of the hen oviduct. Analysis revealed 135 clones hybridizing to over-expressed transcripts (WI/Ma + WI/Ut), and corresponding to 107 NCBI annotated non-redundant Gallus gallus gene IDs. This combined analysis revealed that the structural proteins highly over-expressed in the white isthmus include collagen X (COL10A1), fibrillin-1 (FBN1) and cysteine rich eggshell membrane protein (CREMP). These results validate previous proteomics studies which have identified collagen X (α-1) and CREMP in soluble eggshell extracts. Genes encoding collagen-processing enzymes such as lysyl oxidase homologs 1, 2 and 3 (LOXL1, LOXL2 and LOXL3), prolyl 4 hydroxylase subunit α-2 and beta polypeptide (P4HA2 and P4HB) as well as peptidyl-prolyl cis-trans isomerase C (PPIC) were also over-expressed. Additionally, genes encoding proteins known to regulate disulfide cross-linking, including sulfhydryl oxidase (QSOX1) and thioredoxin (TXN), were identified which suggests that coordinated up-regulation of genes in the white isthmus is associated with eggshell membrane fibre formation. Conclusions The present study has identified genes associated with the processing of collagen, other structural proteins, and disulfide-mediated cross-linking during eggshell membrane formation in the white isthmus. Identification of these genes will provide new insight into eggshell membrane structure and mechanisms of formation that will assist in the development of selection strategies to improve eggshell quality and food safety of the table egg. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2013-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jingwen Du
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, K1H 8 M5, Canada.
| | - Maxwell T Hincke
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, K1H 8 M5, Canada.
| | - Megan Rose-Martel
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, K1H 8 M5, Canada.
| | | | | | - Larry A Cogburn
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, 19717, USA.
| | - Yves Nys
- INRA, UR83 Recherches Avicoles, F-37380, Nouzilly, France.
| | - Joel Gautron
- INRA, UR83 Recherches Avicoles, F-37380, Nouzilly, France.
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Babich V, Di Sole F. The Na+/H+ Exchanger-3 (NHE3) Activity Requires Ezrin Binding to Phosphoinositide and Its Phosphorylation. PLoS One 2015; 10:e0129306. [PMID: 26042733 PMCID: PMC4455992 DOI: 10.1371/journal.pone.0129306] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 05/08/2015] [Indexed: 11/19/2022] Open
Abstract
Na+/H+ exchanger-3 (NHE3) plays an essential role in maintaining sodium and fluid homeostasis in the intestine and kidney epithelium. Thus, NHE3 is highly regulated and its function depends on binding to multiple regulatory proteins. Ezrin complexed with NHE3 affects its activity via not well-defined mechanisms. This study investigates mechanisms by which ezrin regulates NHE3 activity in epithelial Opossum Kidney cells. Ezrin is activated sequentially by phosphatidylinositol-4,5-bisphosphate (PIP2) binding and phosphorylation of threonine 567. Expression of ezrin lacking PIP2 binding sites inhibited NHE3 activity (-40%) indicating that ezrin binding to PIP2 is required for preserving NHE3 activity. Expression of a phosphomimetic ezrin mutated at the PIP2 binding region was sufficient not only to reverse NHE3 activity to control levels but also to increase its activity (+80%) similar to that of the expression of ezrin carrying the phosphomimetic mutation alone. Calcineurin Homologous Protein-1 (CHP1) is part, with ezrin, of the NHE3 regulatory complex. CHP1-mediated activation of NHE3 activity was blocked by expression of an ezrin variant that could not be phosphorylated but not by an ezrin variant unable to bind PIP2. Thus, for NHE3 activity under baseline conditions not only ezrin phosphorylation, but also ezrin spatial-temporal targeting on the plasma membrane via PIP2 binding is required; however, phosphorylation of ezrin appears to overcome the control of NHE3 transport. CHP1 action on NHE3 activity is not contingent on ezrin binding to PIP2 but rather on ezrin phosphorylation. These findings are important in understanding the interrelation and dynamics of a CHP1-ezrin-NHE3 regulatory complex.
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Affiliation(s)
- Victor Babich
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Francesca Di Sole
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Physiology and Pharmacology Department, Des Moines University, Iowa, United States of America
- * E-mail:
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Nicolao MC, Cumino AC. Biochemical and molecular characterization of the calcineurin in Echinococcus granulosus larval stages. Acta Trop 2015; 146:141-51. [PMID: 25818323 DOI: 10.1016/j.actatropica.2015.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 03/06/2015] [Accepted: 03/10/2015] [Indexed: 01/26/2023]
Abstract
Calcineurin (CaN) is a Ca(2+)-calmodulin activated serine-threonine protein phosphatase that couples the local or global calcium signals, thus controlling important cellular functions in physiological and developmental processes. The aim of this study was to characterize CaN in Echinococcus granulosus (Eg-CaN), a human cestode parasite of clinical importance, both functionally and molecularly. We found that the catalytic subunit isoforms have predicted sequences of 613 and 557 amino acids and are substantially similar to those of the human counterpart, except for the C-terminal end. We also found that the regulatory subunit consists of 169 amino acids which are 87% identical to the human ortholog. We cloned a cDNA encoding for one of the two catalytic subunit isoforms of CaN (Eg-can-A1) as well as the only copy of the Eg-can-B gene, both constitutively transcribed in all Echinococcus larval stages and responsible for generating a functionally active heterodimer. Eg-CaN native enzyme has phosphatase activity, which is enhanced by Ca(2+)/Ni(2+) and reduced by cyclosporine A and Ca(2+) chelators. Participation of Eg-CaN in exocytosis was demonstrated using the FM4-64 probe and Eg-CaN-A was immunolocalized in the cytoplasm of tegumental cells, suckers and excretory bladder of protoscoleces. We also showed that the Eg-can-B transcripts were down-regulated in response to low Ca(2+) intracellular level, in agreement with decreased enzyme activity. Confocal microscopy revealed a striking pattern of Eg-CaN-A in discrete fluorescent spots in the protoscolex posterior bladder and vesicularized protoscoleces beginning the vesicular differentiation. In contrast, Eg-CaN-A was undetectable during the pre-microcyst closing stage while a high DDX-like RNA helicase expression was evidenced. Finally, we identified and analyzed the expression of CaN-related endogenous regulators.
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Affiliation(s)
- María Celeste Nicolao
- Laboratorio de Zoonosis Parasitarias, Departamento de Biología, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Nivel Cero, 7600 Mar del Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Andrea C Cumino
- Laboratorio de Zoonosis Parasitarias, Departamento de Biología, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Nivel Cero, 7600 Mar del Plata, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina; Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Nivel 2, 7600 Mar del Plata, Argentina.
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Prognostic significance of SLC9A9 in patients with resectable esophageal squamous cell carcinoma. Tumour Biol 2015; 36:6797-803. [PMID: 25835977 DOI: 10.1007/s13277-015-3392-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/25/2015] [Indexed: 12/24/2022] Open
Abstract
The survival rate of esophageal squamous cell cancer (ESCC) patients is still dismal. Therefore, novel prognostic biomarkers are critically needed for patients with ESCC. SLC9A9 has been reported to be downregulated in hormone-sensitive prostate cancer; however, the correlations between SLC9A9 and ESCC prognosis are unclear. The aim of this study is to evaluate the expression and prognostic significance of SLC9A9 in resectable ESCC. Fresh frozen or paraffin-embedded samples were collected from 167 or 59 patients with resectable ESCC, respectively. The expression of SLC9A9 was assessed by reverse transcription and quantitative real-time polymerase chain reaction analysis (167 patients) and immunohistochemistry (61 patients). The expression of SLC9A9 was not associated with patient clinicopathological characteristics at both transcription and protein levels. The 5-year overall survival in the high SLC9A9 messenger RNA (mRNA) group (n = 106) was poorer than that in the low expression group (n = 61) (34.6 vs. 65.9 %, P < 0.001). Notably, higher SLC9A9 protein expression was also correlated with lower 5-year overall survival (33.1 vs. 66.5 %, P = 0.023). Moreover, multivariate analysis revealed that SLC9A9 mRNA (HR, 2.41; 95 % CI, 1.47-3.97; P = 0.001) and protein (HR, 2.31; 95 %CI, 1.06-5.02; P = 0.034) were independent prognostic factors. In conclusion, the expression of SLC9A9 can be a prognostic predictor for ESCC.
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Abstract
Tescalcin (TESC) is an EF-hand calcium binding protein that is differentially expressed in several tissues, however it is not reported that the expression and functional roles of TESC in colorectal cancer. Levels of messenger RNA (mRNA) and protein expression of TESC in colorectal cancer tissues were assessed using RT-PCR, real time PCR, immunohistochemistry, and clinicopathologic analyses. Quantitative analysis of TESC levels in serum specimens was performed using sandwich ELISA. Colorectal cancer cells transfected with TESC small interfering RNA and short hairpin RNA were examined in cell proliferation assays, phospho-MAPK array, and mouse xenograft models. Here we demonstrated that TESC is overexpressed in colorectal cancer (CRC), but was not expressed in normal mucosa and premalignant dysplastic lesions. Furthermore, serum TESC levels were elevated in patients with CRC. Knockdown of TESC inhibited the Akt-dependent NF-κB pathway and decreased cell survival in vitro. Depletion of TESC reduced tumor growth in a CRC xenograft model. Thus, TESC is a potential diagnostic marker and oncotarget in colorectal cancer.
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22
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Pan MG, Xiong Y, Chen F. NFAT gene family in inflammation and cancer. Curr Mol Med 2013; 13:543-54. [PMID: 22950383 DOI: 10.2174/1566524011313040007] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 08/04/2012] [Accepted: 08/10/2012] [Indexed: 01/28/2023]
Abstract
Calcineurin-NFAT signaling is critical for numerous aspects of vertebrate function during and after embryonic development. Initially discovered in T cells, the NFAT gene family, consisting of five members, regulates immune system, inflammatory response, angiogenesis, cardiac valve formation, myocardial development, axonal guidance, skeletal muscle development, bone homeostasis, development and metastasis of cancer, and many other biological processes. In this review we will focus on the NFAT literature relevant to the two closely related pathological systems: inflammation and cancer.
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Affiliation(s)
- M-G Pan
- Division of Oncology and Hematology, Kaiser Permanente Medical Center, Santa Clara, CA 95051, USA.
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Lee JI, Mukherjee S, Yoon K, Dwivedi M, Bandyopadhyay J. The multiple faces of calcineurin signaling in Caenorhabditis elegans: Development, behaviour and aging. J Biosci 2013; 38:417-31. [DOI: 10.1007/s12038-013-9319-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Zaun HC, Shrier A, Orlowski J. N-myristoylation and Ca2+ binding of calcineurin B homologous protein CHP3 are required to enhance Na+/H+ exchanger NHE1 half-life and activity at the plasma membrane. J Biol Chem 2012; 287:36883-95. [PMID: 22984264 DOI: 10.1074/jbc.m112.394700] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Calcineurin B homologous proteins (CHP) are N-myristoylated, EF-hand Ca(2+)-binding proteins that regulate multiple cellular processes, including intracellular pH homeostasis. Previous work has shown that the heart-enriched isoform, CHP3, regulates the plasmalemmal Na(+)/H(+) exchanger NHE1 isoform by enhancing its rate of oligosaccharide maturation and exocytosis as well as its half-life and transport activity at the cell surface (Zaun, H. C., Shrier, A., and Orlowski, J. (2008) J. Biol. Chem. 283, 12456-12467). However, the molecular basis for this effect is not well understood. In this report, we investigated whether the N-myristoylation and Ca(2+)-binding domains of CHP3 are important elements for regulating NHE1. Mutation of residues essential for either N-myristoylation (G2A) or calcium binding (D123A) did not prevent the interaction of CHP3 with NHE1, although the D123A mutant no longer showed elevated binding to NHE1 in the presence of Ca(2+) when assessed using in vitro binding assays. Disruption of either site also did not impair the ability of CHP3 to stimulate the biosynthetic processing and trafficking of NHE1 to the plasma membrane nor did it affect the H(+) sensitivity of the exchanger. However, they did significantly reduce the cell surface half-life and near maximal transport velocity of NHE1 to a similar extent. Simultaneous mutation of both sites (G2A/D123A) gave results identical to the individual substitutions. This finding suggests that both domains in CHP3 are interdependent and may function cooperatively as a Ca(2+)-myristoyl switch mechanism to selectively stabilize the NHE1·CHP3 complex at the cell surface in a conformation that promotes optimal transport activity.
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Affiliation(s)
- Hans C Zaun
- Department of Physiology, McGill University, Montréal, Québec H3G 1Y6, Canada
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25
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Di Sole F, Vadnagara K, Moe OW, Babich V. Calcineurin homologous protein: a multifunctional Ca2+-binding protein family. Am J Physiol Renal Physiol 2012; 303:F165-79. [PMID: 22189947 PMCID: PMC3404583 DOI: 10.1152/ajprenal.00628.2011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 05/17/2012] [Indexed: 12/13/2022] Open
Abstract
The calcineurin homologous protein (CHP) belongs to an evolutionarily conserved Ca(2+)-binding protein subfamily. The CHP subfamily is composed of CHP1, CHP2, and CHP3, which in vertebrates share significant homology at the protein level with each other and between other Ca(2+)-binding proteins. The CHP structure consists of two globular domains containing from one to four EF-hand structural motifs (calcium-binding regions composed of two helixes, E and F, joined by a loop), the myristoylation, and nuclear export signals. These structural features are essential for the function of the three members of the CHP subfamily. Indeed, CHP1-CHP3 have multiple and diverse essential functions, ranging from the regulation of the plasma membrane Na(+)/H(+) exchanger protein function, to carrier vesicle trafficking and gene transcription. The diverse functions attributed to the CHP subfamily rendered an understanding of its action highly complex and often controversial. This review provides a comprehensive and organized examination of the properties and physiological roles of the CHP subfamily with a view to revealing a link between CHP diverse functions.
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Affiliation(s)
- Francesca Di Sole
- Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, TX 75390-8885, USA.
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Moore DL, Goldberg JL. Multiple transcription factor families regulate axon growth and regeneration. Dev Neurobiol 2012; 71:1186-211. [PMID: 21674813 DOI: 10.1002/dneu.20934] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Understanding axon regenerative failure remains a major goal in neuroscience, and reversing this failure remains a major goal for clinical neurology. Although an inhibitory central nervous system environment clearly plays a role, focus on molecular pathways within neurons has begun to yield fruitful insights. Initial steps forward investigated the receptors and signaling pathways immediately downstream of environmental cues, but recent work has also shed light on transcriptional control mechanisms that regulate intrinsic axon growth ability, presumably through whole cassettes of gene target regulation. Here we will discuss transcription factors that regulate neurite growth in vitro and in vivo, including p53, SnoN, E47, cAMP-responsive element binding protein (CREB), signal transducer and activator of transcription 3 (STAT3), nuclear factor of activated T cell (NFAT), c-Jun activating transcription factor 3 (ATF3), sex determining region Ybox containing gene 11 (Sox11), nuclear factor κ-light chain enhancer of activated B cells (NFκB), and Krüppel-like factors (KLFs). Revealing the similarities and differences among the functions of these transcription factors may further our understanding of the mechanisms of transcriptional regulation in axon growth and regeneration.
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Affiliation(s)
- Darcie L Moore
- Bascom Palmer Eye Institute and the Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Florida, USA
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27
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Megakaryocyte development is normal in mice with targeted disruption of Tescalcin. Exp Cell Res 2012; 318:662-9. [PMID: 22285131 DOI: 10.1016/j.yexcr.2012.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 12/30/2011] [Accepted: 01/05/2012] [Indexed: 11/23/2022]
Abstract
BACKGROUND Tescalcin is an EF-hand calcium-binding protein that interacts with the Na+/H+ exchanger 1 (NHE1). Levay and Slepak recently proposed a role for tescalcin in megakaryopoiesis that was independent of NHE1 activity. Their studies using K562 and HEL cell lines, and human CD34+ hematopoietic stem cells suggested an essential role for tescalcin in megakaryocyte differentiation. OBJECTIVE To study the role of tescalcin in megakaryocyte development using a murine model of megakaryopoiesis. METHODS We generated a mouse with targeted disruption of tescalcin and investigated megakaryocyte development. RESULTS Tescalcin-deficient mice had a normal number of megakaryocytes and platelets. The morphology, polyploidization profile, and expression of Fli-1 in bone marrow-derived megakaryocytes were also normal. CONCLUSION Tescalcin does not appear to be necessary for normal megakaryocyte development.
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Wagner J, Allman E, Taylor A, Ulmschneider K, Kovanda T, Ulmschneider B, Nehrke K, Peters MA. A calcineurin homologous protein is required for sodium-proton exchange events in the C. elegans intestine. Am J Physiol Cell Physiol 2011; 301:C1389-403. [PMID: 21865588 DOI: 10.1152/ajpcell.00139.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Caenorhabditis elegans defecation is a rhythmic behavior, composed of three sequential muscle contractions, with a 50-s periodicity. The motor program is driven by oscillatory calcium signaling in the intestine. Proton fluxes, which require sodium-proton exchangers at the apical and basolateral intestinal membranes, parallel the intestinal calcium flux. These proton shifts are critical for defecation-associated muscle contraction, nutrient uptake, and longevity. How sodium-proton exchangers are activated in time with intestinal calcium oscillation is not known. The posterior body defecation contraction mutant (pbo-1) encodes a calcium-binding protein with homology to calcineurin homologous proteins, which are putative cofactors for mammalian sodium-proton exchangers. Loss of pbo-1 function results in a weakened defecation muscle contraction and a caloric restriction phenotype. Both of these phenotypes also arise from dysfunctions in pH regulation due to mutations in intestinal sodium-proton exchangers. Dynamic, in vivo imaging of intestinal proton flux in pbo-1 mutants using genetically encoded pH biosensors demonstrates that proton movements associated with these sodium-proton exchangers are significantly reduced. The basolateral acidification that signals the first defecation motor contraction is scant in the mutant compared with a normal animal. Luminal and cytoplasmic pH shifts are much reduced in the absence of PBO-1 compared with control animals. We conclude that pbo-1 is required for normal sodium-proton exchanger activity and may couple calcium and proton signaling events.
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Affiliation(s)
- Jamie Wagner
- Dept. of Biology, Oberlin College, Oberlin, OH 44074, USA
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29
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Li QH, Wang LH, Lin YN, Chang GQ, Li HW, Jin WN, Hu RH, Pang TX. Nuclear accumulation of calcineurin B homologous protein 2 (CHP2) results in enhanced proliferation of tumor cells. Genes Cells 2011; 16:416-26. [PMID: 21392185 DOI: 10.1111/j.1365-2443.2011.01497.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The interaction between calcineurin B homologous protein 2 (CHP2) and Na(+) /H(+) exchanger 1 (NHE1), two membrane proteins, is essential for protecting cells from serum deprivation-induced death. Although four putative EF-hands in CHP2 had been predicted for years, Ca²(+) -binding activities of these motifs have not been tested yet, their role in this process remain poorly understood. To identify Ca²(+) -binding motifs required for the stable formation of CHP2/NHE1 complexes, we developed a mutagenesis-based assay in PS120 cells. We found that (45) Ca²(+) bond to two EF-hand motifs (EF3 and 4) of CHP2 proteins with high affinity. Complex formation between CHP2 and the CHP2 binding domain of NHE1 resulted in a marked increase in the Ca²(+) -binding affinity of CHP2. Co-immunoprecipitation and distribution of GFP-tagged CHP2-EF3m/4m also indicated that Ca²(+) affected the membrane location of CHP2 to interact with NHE1. The C-terminal region of CHP2 contains a nuclear export sequence (NES). When the six leucines of NES were mutated to alanines, the resulting CHP2 protein was predominantly localized to the nucleus. Furthermore, mutation of the NES resulted in enhanced proliferation and oncogenic potential of HeLa cells. Together, these results show that calcium and NES control the subcellular distribution of CHP2 and then distinctively regulate cell proliferation.
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Affiliation(s)
- Qing-Hua Li
- State key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China
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König A, Fernandez-Zapico ME, Ellenrieder V. Primers on molecular pathways--the NFAT transcription pathway in pancreatic cancer. Pancreatology 2010; 10:416-22. [PMID: 20720442 PMCID: PMC3114309 DOI: 10.1159/000315035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The calcineurin-responsive nuclear factor of activated T cells (NFAT) family of transcription factors was originally identified as a group of inducible nuclear proteins, which regulate transcription during T lymphocyte activation. However, following their initial discovery, a multitude of studies quickly established that NFAT proteins are also expressed in cells outside the immune system, where they participate in the regulation of the expression of genes influencing cell growth and differentiation. Ectopic activation of individual NFAT members is now recognized as an important aspect for oncogenic transformation in several human malignancies, most notably in pancreatic cancer. Sustained activation of the Ca(2+)/calcineurin/NFAT signaling pathway has emerged as a powerful regulatory principle governing pancreatic cancer cell growth. Activated NFAT proteins form complexes with key oncogenic proteins to regulate the transcription of master cell cycle regulators and proteins with functions in cell survival, migration and angiogenesis. This review pays particular attention to recent advances in our understanding of how the NFAT transcription pathway controls gene expression during development and progression of pancreatic cancer. and IAP.
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Affiliation(s)
- Alexander König
- Signal Transduction and Transcription Laboratory, Department of Gastroenterology and Endocrinology, Philipps-University of Marburg, Marburg, Germany,Division of Oncology Research and Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, Minn., USA
| | - Martin E. Fernandez-Zapico
- Division of Oncology Research and Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, Minn., USA
| | - Volker Ellenrieder
- Signal Transduction and Transcription Laboratory, Department of Gastroenterology and Endocrinology, Philipps-University of Marburg, Marburg, Germany,*Volker Ellenrieder, MD, Signal Transduction and Transcription Laboratory, Department of Gastroenterology and Endocrinology, Philipps-University of Marburg, DE–35043 Marburg (Germany), Tel. +49 642 1286 6460, Fax +49 642 1286 8922, E-Mail
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Jiménez-Vidal M, Srivastava J, Putney LK, Barber DL. Nuclear-localized calcineurin homologous protein CHP1 interacts with upstream binding factor and inhibits ribosomal RNA synthesis. J Biol Chem 2010; 285:36260-6. [PMID: 20720019 DOI: 10.1074/jbc.m110.165555] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Calcineurin homologous protein 1 (CHP1) is a widely expressed, 22-kDa myristoylated EF-hand Ca(2+)-binding protein that shares a high degree of similarity with the regulatory B subunit of calcineurin (65%) and with calmodulin (59%). CHP1 localizes to the plasma membrane, the Golgi apparatus, and the nucleus and functions to regulate trafficking of early secretory vesicles, activation of T cells, and expression and transport of the Na-H exchanger NHE1. Although CHP1 contains nuclear export signals, whether its nuclear and cytoplasmic localization is regulated and has distinct functions remain unknown. We show that CHP1 is predominantly in the nucleus in quiescent fibroblasts, is translocated to cytoplasmic compartments with growth medium, and that translocation is inhibited by mutations in the nuclear export motifs. In a screen for proteins co-precipitating with CHP1 in quiescent cells we identified the upstream binding factor UBF, a DNA-binding protein and component of the RNA polymerase I complex regulating RNA synthesis. The CHP1-UBF interaction is restricted to the nucleus and inhibited by Ca(2+). Nuclear retention of CHP1 attenuates the abundance of UBF in the nucleolus and inhibits RNA synthesis when quiescent cells are transferred to growth medium. These data show UBF as a newly identified CHP1-binding protein and regulation of RNA synthesis as a newly identified function for nuclear-localized CHP1, which is distinct from CHP1 functions in the cytosol.
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Affiliation(s)
- Maite Jiménez-Vidal
- Department of Cell and Tissue Biology, University of California, San Francisco, California 94143, USA
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Ren Y, Wang ZX, Wei Q. Mechanism of activation of Saccharomyces cerevisiae calcineurin by Mn2+. Biol Chem 2009; 390:1155-62. [PMID: 19558332 DOI: 10.1515/bc.2009.108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Saccharomyces cerevisiae calcineurin (CN) consists of a catalytic subunit CNA1 or CNA2 and a regulatory subunit CNB1. The kinetics of activation of yeast CN holoenzymes and their catalytic domains by Mn2+ were investigated. We report that the in vitro phosphatase reaction activated by Mn2+ typically has a pronounced initial lag phase caused by slow conformational rearrangement of the holoenzyme-Mn2+. A similar lag phase was detected using just the catalytic domain of yeast CN, indicating that the slowness of Mn2+-induced conformational change of CN results from a rearrangement within the catalytic domain. The Mn2+-activation of CN was reversible. The dissociation constant of the CN heterodimer containing the CNA2 subunit in the presence of Mn2+ was 3-fold higher than that of CN containing the CNA1 subunit and that of the catalytic domains of CNA1 and CNA2, pointing to differences between the residues surrounding the Mn2+-binding sites of CNA1 and CNA2.
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Affiliation(s)
- Yan Ren
- Department of Biochemistry and Molecular Biology, Beijing Normal University, Beijing Key Laboratory, Beijing 100875, P.R. China
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33
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Erdmann F, Weiwad M, Kilka S, Karanik M, Pätzel M, Baumgrass R, Liebscher J, Fischer G. The novel calcineurin inhibitor CN585 has potent immunosuppressive properties in stimulated human T cells. J Biol Chem 2009; 285:1888-98. [PMID: 19923214 DOI: 10.1074/jbc.m109.024844] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The Ca2+/calmodulin-dependent protein phosphatase calcineurin is a key mediator in antigen-specific T cell activation. Thus, inhibitors of calcineurin, such as cyclosporin A or FK506, can block T cell activation and are used as immunosuppressive drugs to prevent graft-versus-host reactions and autoimmune diseases. In this study we describe the identification of 2,6- diaryl-substituted pyrimidine derivatives as a new class of calcineurin inhibitors, obtained by screening of a substance library. By rational design of the parent compound we have attained the derivative 6-(3,4-dichloro-phenyl)-4-(N,N-dimethylaminoethylthio)-2-phenyl-pyrimidine (CN585) that noncompetitively and reversibly inhibits calcineurin activity with a K(i) value of 3.8 mum. This derivative specifically inhibits calcineurin without affecting other Ser/Thr protein phosphatases or peptidyl prolyl cis/trans isomerases. CN585 shows potent immunosuppressive effects by inhibiting NFAT nuclear translocation and transactivation, cytokine production, and T cell proliferation. Moreover, the calcineurin inhibitor exhibits no cytotoxicity in the effective concentration range. Therefore, calcineurin inhibition by CN585 may represent a novel promising strategy for immune intervention.
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Affiliation(s)
- Frank Erdmann
- Max Planck Research Unit for Enzymology of Protein Folding, Weinbergweg 22, D-06120 Halle/Saale.
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Di Sole F, Babich V, Moe OW. The calcineurin homologous protein-1 increases Na(+)/H(+) -exchanger 3 trafficking via ezrin phosphorylation. J Am Soc Nephrol 2009; 20:1776-86. [PMID: 19556366 DOI: 10.1681/asn.2008121255] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The Na(+)/H(+)-exchanger 3 (NHE3) is essential for regulation of Na(+) transport in the renal and intestinal epithelium. Although changes in cell surface abundance control NHE3 function, the molecular signals that regulate NHE3 surface expression are not well defined. We found that overexpression of the calcineurin homologous protein-1 (CHP1) in opossum kidney cells increased NHE3 transport activity, surface protein abundance, and ezrin phosphorylation. CHP1 knockdown by small interfering RNA had the opposite effects. Overexpression of wild-type ezrin increased both NHE3 transport activity and surface protein abundance, confirming that NHE3 is downstream of ezrin. Expression of a pseudophosphorylated ezrin enhanced these effects, whereas expression of an ezrin variant that could not be phosphorylated prevented the downstream effects on NHE3. Furthermore, CHP1 knockdown reversed the activation of NHE3 by wild-type ezrin but not by the pseudophosphorylated ezrin. Taken together, these results demonstrate that CHP1 increases NHE3 abundance and constitutive function in a manner dependent on ezrin phosphorylation.
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Affiliation(s)
- Francesca Di Sole
- Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-8885, USA.
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35
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Aspergillus fumigatus calcipressin CbpA is involved in hyphal growth and calcium homeostasis. EUKARYOTIC CELL 2009; 8:511-9. [PMID: 19252123 DOI: 10.1128/ec.00336-08] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Calcineurin is a conserved protein phosphatase that plays a critical role in Ca(2+) signaling and stress responses. Previously, a new class of conserved calcineurin-binding proteins, the calcipressins, was identified. However, the role of these proteins remains controversial, and both inhibitory and stimulatory effects on calcineurin were observed. In this study, we investigate the role of CbpA, the Aspergillus fumigatus member of the calcipressin family, and report that deletion of the cbpA gene resulted in reduced hyphal growth and limited attenuated virulence. Interestingly, under high-calcium-level conditions, the DeltacbpA strain displayed improved Ca(2+) tolerance compared to the wild-type strain and revealed increased expression of vcxA, chsA, and cnaA, which encode the vacuolar Ca(2+)/H(+) exchanger VcxA, chitin synthase A, and the calcineurin catalytic subunit CnaA, respectively. The increased transcript levels of these three genes were reversed in the presence of the calcineurin inhibitor FK506, indicating a calcineurin-dependent mechanism. Overexpression of cbpA resulted in decreased transcription of vcxA, chsA, and cnaA, associated with wild-type sensitivity to Ca(2+). Taken together, our study highlights the importance of CbpA in the regulation of hyphal growth and calcium adaptation of A. fumigatus and provides evidence that CbpA may serve as a feedback inhibitor in some aspects of calcineurin functions.
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36
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Li GD, Zhang X, Li R, Wang YD, Wang YL, Han KJ, Qian XP, Yang CG, Liu P, Wei Q, Chen WF, Zhang J, Zhang Y. CHP2 Activates the Calcineurin/Nuclear Factor of Activated T Cells Signaling Pathway and Enhances the Oncogenic Potential of HEK293 Cells. J Biol Chem 2008; 283:32660-8. [DOI: 10.1074/jbc.m806684200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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37
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Genetic dissociation of ethanol sensitivity and memory formation in Drosophila melanogaster. Genetics 2008; 178:1895-902. [PMID: 18430923 DOI: 10.1534/genetics.107.084582] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ad hoc genetic correlation between ethanol sensitivity and learning mechanisms in Drosophila could overemphasize a common process supporting both behaviors. To challenge directly the hypothesis that these mechanisms are singular, we examined the learning phenotypes of 10 new strains. Five of these have increased ethanol sensitivity, and the other 5 do not. We tested place and olfactory memory in each of these lines and found two new learning mutations. In one case, altering the tribbles gene, flies have a significantly reduced place memory, elevated olfactory memory, and normal ethanol response. In the second case, mutation of a gene we name ethanol sensitive with low memory (elm), place memory was not altered, olfactory memory was sharply reduced, and sensitivity to ethanol was increased. In sum, however, we found no overall correlation between ethanol sensitivity and place memory in the 10 lines tested. Furthermore, there was a weak but nonsignificant correlation between ethanol sensitivity and olfactory learning. Thus, mutations that alter learning and sensitivity to ethanol can occur independently of each other and this implies that the set of genes important for both ethanol sensitivity and learning is likely a subset of the genes important for either process.
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38
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Wang YL, Wang Y, Tong L, Wei Q. Overexpression of calcineurin B subunit (CnB) enhances the oncogenic potential of HEK293 cells. Cancer Sci 2008; 99:1100-8. [PMID: 18422742 PMCID: PMC11158933 DOI: 10.1111/j.1349-7006.2008.00799.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Calcineurin (CaN) is a Ca(2+)/calmodulin (CaM)-stimulated protein phosphatase. It is a heterodimeric enzyme consisting of a catalytic A subunit (CnA) and a Ca(2+)-binding regulatory B subunit (CnB). CaN's key role in vivo is well known, while the function of CnB keeps unclear except that it acts as a regulator of CaN. The present paper shows that CnB overexpression promotes proliferation of human embryonic kidney HEK293 cells by comparing with vector control cells in the complete or serum reduced medium. Furthermore, stable CnB transfectants showed dramatically improved growth in soft agar. And the migration ability of CnB overexpressors also was enhanced remarkably. But in the progress of transformation, the activity of CaN remained unchanged between CnB overexpressors and controls. Therefore, CnB, rather than CaN, is involved in the proliferation promotion of HEK293 cells. Subsequently, 11 proteins with different expression levels between CnB transfectants and controls were identified using two-dimensional gel electrophoresis and electrospray ionization time-of-fight mass spectrometry. Therein, the expression of heat shock protein 27 (HSP27) and protein DJ-1 increased along with CnB overexpression. The important role of CnB in cell neoplastic transformation was found and the possible mechanism was analyzed.
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MESH Headings
- Blotting, Western
- Calcineurin/physiology
- Cell Movement
- Cell Proliferation
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Cells, Cultured
- Colony-Forming Units Assay
- Culture Media, Serum-Free
- Electrophoresis, Gel, Two-Dimensional
- Heat-Shock Proteins/metabolism
- Humans
- Immunoprecipitation
- Kidney/embryology
- Liver/cytology
- Liver/metabolism
- Oncogene Proteins/metabolism
- Protein Subunits
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/isolation & purification
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Spectrometry, Mass, Electrospray Ionization
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Affiliation(s)
- Yan-Li Wang
- Department of Biochemistry and Molecular Biology, Beijing Normal University, Beijing Key Laboratory, Beijing 100875, China
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39
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Mellström B, Savignac M, Gomez-Villafuertes R, Naranjo JR. Ca2+-Operated Transcriptional Networks: Molecular Mechanisms and In Vivo Models. Physiol Rev 2008; 88:421-49. [DOI: 10.1152/physrev.00041.2005] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Calcium is the most universal signal used by living organisms to convey information to many different cellular processes. In this review we present well-known and recently identified proteins that sense and decode the calcium signal and are key elements in the nucleus to regulate the activity of various transcriptional networks. When possible, the review also presents in vivo models in which the genes encoding these calcium sensors-transducers have been modified, to emphasize the critical role of these Ca2+-operated mechanisms in many physiological functions.
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40
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Zaun HC, Shrier A, Orlowski J. Calcineurin B homologous protein 3 promotes the biosynthetic maturation, cell surface stability, and optimal transport of the Na+/H+ exchanger NHE1 isoform. J Biol Chem 2008; 283:12456-67. [PMID: 18321853 DOI: 10.1074/jbc.m800267200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calcineurin B homologous protein (CHP) 1 and 2 are Ca(2+)-binding proteins that modulate several cellular processes, including cytoplasmic pH by positively regulating plasma membrane-type Na(+)/H(+) exchangers (NHEs). Recently another CHP-related protein, termed tescalcin or CHP3, was also shown to interact with the ubiquitous NHE1 isoform, but seemingly suppressed its activity. However, the precise physical and functional nature of this association was not examined in detail. In this study, biochemical and cellular studies were undertaken to further delineate this relationship. Glutathione S-transferase-NHE1 fusion protein pulldown assays revealed that full-length CHP3 binds directly to the proximal juxtamembrane C-terminal region (amino acids 505-571) of rat NHE1 in the same region that binds CHP1 and CHP2. The interaction was further validated by coimmunoprecipitation and coimmunolocalization experiments using full-length CHP3 and wild-type NHE1 in transfected Chinese hamster ovary AP-1 cells. Simultaneous mutation of four hydrophobic residues within this region ((530)FLDHLL(535)) to either Ala, Gln, or Arg (FL-A, FL-Q, or FL-R) abrogated this interaction both in vitro and in intact cells. The NHE1 mutants were sorted properly to the cell surface but showed markedly reduced (FL-A) or minimal (FL-R and FL-Q) activity. Interestingly, and contrary to an earlier finding, ectopic coexpression of CHP3 up-regulated the cell surface activity of wild-type NHE1. This stimulation was not observed with the CHP3 binding-defective mutants. Mechanistically, overexpression of CHP3 did not alter the H(+) sensitivity of wild-type NHE1 but rather promoted its biosynthetic maturation and half-life at the cell surface, thereby increasing the steady-state abundance of functional NHE1 protein.
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Affiliation(s)
- Hans C Zaun
- Department of Physiology, McGill University, Montréal, Québec H3G 1Y6, Canada
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Shen X, Li H, Ou Y, Tao W, Dong A, Kong J, Ji C, Yu S. The secondary structure of calcineurin regulatory region and conformational change induced by calcium/calmodulin binding. J Biol Chem 2008; 283:11407-13. [PMID: 18296442 DOI: 10.1074/jbc.m708513200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The protein serine/threonine phosphatase calcineurin (CN) is activated by calmodulin (CaM) in response to intracellular calcium mobilization. A widely accepted model for CN activation involves displacement of the CN autoinhibitory peptide (CN(467-486)) from the active site upon binding of CaM. However, CN activation requires calcium binding both to the low affinity sites of CNB and to CaM, and previous studies did not dissect the individual contributions of CNB and CaM to displacement of the autoinhibitory peptide from the active site. In this work we have produced separate CN fragments corresponding to the CNA regulatory region (CNRR(381-521), residues 381-521), the CNA catalytic domain truncated at residue 341, and the CNA-CNB heterodimer with CNA truncated at residue 380 immediately after the CNB binding helix. We show that the separately expressed regulatory region retains its ability to inhibit CN phosphatase activity of the truncated CN341 and CN380 and that the inhibition can be reversed by calcium/CaM binding. Tryptophan fluorescence quenching measurements further indicate that the isolated regulatory region inhibits CN activity by occluding the catalytic site and that CaM binding exposes the catalytic site. The results provide new support for a model in which calcium binding to CNB enables CaM binding to the CNA regulatory region, and CaM binding then instructs an activating conformational change of the regulatory region that does not depend further on CNB. Moreover, the secondary structural content of the CNRR(381-521) was tentatively addressed by Fourier transform infrared spectroscopy. The results indicate that the secondary structure of CNRR(381-521) fragment is predominantly random coil, but with significant amount of beta-strand and alpha-helix structures.
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Affiliation(s)
- Xianrong Shen
- Department of Chemistry and Institutes of Biomedical Science and Institute of Genetics, School of Life Science, Fudan University, Shanghai 200433, China
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Jeong D, Kim JM, Cha H, Oh JG, Park J, Yun SH, Ju ES, Jeon ES, Hajjar RJ, Park WJ. PICOT attenuates cardiac hypertrophy by disrupting calcineurin-NFAT signaling. Circ Res 2008; 102:711-9. [PMID: 18258855 DOI: 10.1161/circresaha.107.165985] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PICOT (protein kinase C-interacting cousin of thioredoxin) was previously shown to inhibit pressure overload-induced cardiac hypertrophy, concomitant with an increase in ventricular function and cardiomyocyte contractility. The combined analyses of glutathione S-transferase pull-down experiments and mass spectrometry enabled us to determine that PICOT directly interacts with muscle LIM protein (MLP) via its carboxyl-terminal half (PICOT-C). It was also shown that PICOT colocalizes with MLP in the Z-disc. MLP is known to play a role in anchoring calcineurin to the Z-disc in the sarcomere, which is critical for calcineurin-NFAT (nuclear factor of activated T cells) signaling. We, therefore, suggested that PICOT may affect calcineurin-NFAT signaling through its interaction with MLP. Consistent with this hypothesis, PICOT, or more specifically PICOT-C, abrogated phenylephrine-induced increases in calcineurin phosphatase activity, NFAT dephosphorylation/nuclear translocation, and NFAT-dependent transcriptional activation in neonatal cardiomyocytes. In addition, pressure overload-induced upregulation of NFAT target genes was significantly diminished in the hearts of PICOT-overexpressing transgenic mice. PICOT interfered with MLP-calcineurin interactions in a dose-dependent manner. Moreover, calcineurin was displaced from the Z-disc, concomitant with an abrogated interaction between calcineurin and MLP, in the hearts of PICOT transgenic mice. Replenishment of MLP restored the hypertrophic responses and the increase in calcineurin phosphatase activity that was inhibited by PICOT in phenylephrine-treated cardiomyocytes. Finally, PICOT-C inhibited cardiac hypertrophy to an extent that was comparable to that of full-length PICOT. Taken together, these data suggest that PICOT inhibits cardiac hypertrophy largely by negatively regulating calcineurin-NFAT signaling via disruption of the MLP-calcineurin interaction.
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Affiliation(s)
- Dongtak Jeong
- Global Research Laboratory and Department of Life Science, Gwangju Institute of Science and Technology, Gwangju, Korea
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Zhang Y, Lin DH, Wang ZJ, Jin Y, Yang B, Wang WH. K restriction inhibits protein phosphatase 2B (PP2B) and suppression of PP2B decreases ROMK channel activity in the CCD. Am J Physiol Cell Physiol 2008; 294:C765-73. [PMID: 18184875 DOI: 10.1152/ajpcell.00528.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We used Western blot analysis to examine the effect of dietary K intake on the expression of serine/threonine protein phosphatase in the kidney. K restriction significantly decreased the expression of catalytic subunit of protein phosphatase (PP)2B but increased the expression of PP2B regulatory subunit in both rat and mouse kidney. However, K depletion did not affect the expression of PP1 and PP2A. Treatment of M-1 cells, mouse cortical collecting duct (CCD) cells, or 293T cells with glucose oxidase (GO), which generates superoxide anions through glucose metabolism, mimicked the effect of K restriction on PP2B expression and significantly decreased expression of PP2B catalytic subunits. However, GO treatment increased expression of regulatory subunit of PP2B and had no effect on expression of PP1, PP2A, and protein tyrosine phosphatase 1D. Moreover, deletion of gp91-containing NADPH oxidase abolished the effect of K depletion on PP2B. Thus superoxide anions or related products may mediate the inhibitory effect of K restriction on the expression of PP2B catalytic subunit. We also used patch-clamp technique to study the effect of inhibiting PP2B on renal outer medullary K (ROMK) channels in the CCD. Application of cyclosporin A or FK506, inhibitors of PP2B, significantly decreased ROMK channels, and the effect of PP2B inhibitors was abolished by blocking p38 mitogen-activated protein kinase (MAPK) and ERK. Furthermore, Western blot demonstrated that inhibition of PP2B with cyclosporin A or small interfering RNA increased the phosphorylation of ERK and p38 MAPK. We conclude that K restriction suppresses the expression of PP2B catalytic subunits and that inhibition of PP2B decreases ROMK channel activity through stimulation of MAPK in the CCD.
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Affiliation(s)
- Yan Zhang
- Department of Pharmacology, Harbin Medical University, Harbin, China
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Liu YV, Hubbi ME, Pan F, McDonald KR, Mansharamani M, Cole RN, Liu JO, Semenza GL. Calcineurin promotes hypoxia-inducible factor 1alpha expression by dephosphorylating RACK1 and blocking RACK1 dimerization. J Biol Chem 2007; 282:37064-73. [PMID: 17965024 PMCID: PMC3754800 DOI: 10.1074/jbc.m705015200] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oxygen homeostasis represents an essential organizing principle of metazoan evolution and biology. Hypoxia-inducible factor 1 (HIF-1) is a master regulator of transcriptional responses to changes in O2 concentration. HIF-1 is a heterodimer of HIF-1alpha and HIF-1beta subunits. O2-dependent degradation of the HIF-1alpha subunit is mediated by prolyl hydroxylase, von Hippel-Lindau protein (VHL)/Elongin-C E3 ubiquitin ligase, and the proteasome. O2-independent degradation of HIF-1alpha is regulated by the competition of RACK1 and HSP90 for binding to HIF-1alpha. RACK1 binding results in the recruitment of the Elongin-C E3 ubiquitin ligase, leading to VHL-independent ubiquitination and degradation of HIF-1alpha. In this report, we show that calcineurin inhibits the ubiquitination and proteasomal degradation of HIF-1alpha. Calcineurin is a serine/threonine phosphatase that is activated by calcium and calmodulin. The phosphatase activity of calcineurin is required for its regulation of HIF-1alpha. RACK1 binds to the catalytic domain of calcineurin and is required for HIF-1alpha degradation induced by the calcineurin inhibitor cyclosporine A. Elongin-C and HIF-1alpha each bind to RACK1 and dimerization of RACK1 is required to recruit Elongin-C to HIF-1alpha. Phosphorylation of RACK1 promotes its dimerization and dephosphorylation by calcineurin inhibits dimerization. Serine 146 within the dimerization domain is phosphorylated and mutation of serine 146 impairs RACK1 dimerization and HIF-1alpha degradation. These results indicate that intracellular calcium levels can regulate HIF-1alpha expression by modulating calcineurin activity and RACK1 dimerization.
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Affiliation(s)
- Ye V. Liu
- Vascular Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Maimon E. Hubbi
- Vascular Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Graduate Training Program in Cellular and Molecular Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Fan Pan
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Karin R. McDonald
- Vascular Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Malini Mansharamani
- Mass Spectrometry/Proteomics Facility, Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Robert N. Cole
- Mass Spectrometry/Proteomics Facility, Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Jun O. Liu
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Gregg L. Semenza
- Vascular Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Departments of Pediatrics, Medicine, Oncology, and Radiation Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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Meima ME, Mackley JR, Barber DL. Beyond ion translocation: structural functions of the sodium-hydrogen exchanger isoform-1. Curr Opin Nephrol Hypertens 2007; 16:365-72. [PMID: 17565280 DOI: 10.1097/mnh.0b013e3281bd888d] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PURPOSE OF REVIEW The sodium-hydrogen exchanger isoform-1 (NHE1) functions in intracellular pH and cell volume homeostasis by catalyzing an electroneutral exchange of extracellular sodium and intracellular hydrogen. Recent studies have revealed the structural functions of NHE1 as an anchor for actin filaments and a scaffold for an ensemble of signaling proteins. This review highlights how these functions contribute to NHE1 regulation of biochemical events and cell behaviors. RECENT FINDINGS New data confirming nontransport structural functions of NHE1 suggest reexamining how NHE1 regulates cell functions. Cell survival, cell substrate adhesion, and organization of the actin cytoskeleton are confirmed to be regulated through actin anchoring by NHE1 and likely by NHE1-dependent scaffolding of signaling proteins. A role for NHE1 in mechanotransduction is emerging and a challenge of future studies is to determine whether structural functions of NHE1 are important for mechanoresponsiveness. SUMMARY This review highlights evidence for the nontransport functions of NHE1 and describes how the structural functions are integrated with ion translocation to regulate a range of cellular processes. Nontransporting features of NHE1 are analogous to recently observed nonconducting actions of ion channels in regulating cell behaviors and represent an emerging paradigm of ion transporters as multifunctional proteins.
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Affiliation(s)
- Marcel E Meima
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California 94143, USA
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Matsushita M, Sano Y, Yokoyama S, Takai T, Inoue H, Mitsui K, Todo K, Ohmori H, Kanazawa H. Loss of calcineurin homologous protein-1 in chicken B lymphoma DT40 cells destabilizes Na+/H+ exchanger isoform-1 protein. Am J Physiol Cell Physiol 2007; 293:C246-54. [PMID: 17392381 DOI: 10.1152/ajpcell.00464.2006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
NHE1/SLC9A1 is a ubiquitous isoform of vertebrate Na+/H+ exchangers (NHEs) functioning in maintaining intracellular concentrations of Na+ and H+ ions. Calcineurin homologous protein-1 (CHP1) binds to the hydrophilic region of NHE1 and regulates NHE1 activity but reportedly does not play a role in translocating NHE1 from the endoplasmic reticulum to the plasma membrane. However, an antiport function of NHE1 requiring CHP1 remains to be clarified. Here we established CHP1-deficient chicken B lymphoma DT40 cells by gene targeting to address CHP1 function. CHP1-deficient cells showed extensive decreases in Na+/H+ activities in intact cells. Although NHE1 mRNA levels were not affected, NHE1 protein levels were significantly reduced not only in the plasma membrane but in whole cells. The expression of a CHP1 transgene in CHP1-deficient cells rescued NHE1 protein expression. Expression of mutant forms of CHP1 defective in Ca2+ binding or myristoylation also partially decreased NHE1 protein levels. Knockdown of CHP1 also caused a moderate decrease in NHE1 protein in HeLa cells. These data indicate that CHP1 primarily plays an essential role in stabilization of NHE1 for reaching of NHE1 to the plasma membrane and its exchange activity.
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Affiliation(s)
- Masafumi Matsushita
- Dept. of Biological Sciences, Graduate School of Science, Osaka University, Machikaneyama-cho 1-1, Toyonaka City, Osaka, Japan 560-0043
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Fiedler B, Wollert KC. Targeting calcineurin and associated pathways in cardiac hypertrophy and failure. Expert Opin Ther Targets 2007; 9:963-73. [PMID: 16185152 DOI: 10.1517/14728222.9.5.963] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cardiac hypertrophy occurs in response to long-term increases in haemodynamic load related to a variety of physiological and pathological conditions. Cardiac hypertrophy developing in pathological conditions with increased load often progresses to a decompensated stage with cardiac contractile dysfunction, clinical signs of heart failure and premature death. Cardiac hypertrophy associated with adverse outcomes is said to be maladaptive. Conversely, there are settings where cardiac hypertrophy appears to be purely adaptive (e.g., hypertrophy in response to regular physical exercise). In these circumstances, hypertrophy is associated with preserved contractile performance and a favourable prognosis. Cardiac myocyte hypertrophy is controlled by growth factor receptors and mechanical stress sensors which activate a complex network of signalling pathways. These pathways promote a multitude of qualitative and quantitative changes in gene expression levels in cardiomyocytes. Reprogramming of gene expression, much more than cardiac (myocyte) hypertrophy per se, ultimately determines if cardiac hypertrophy will be adaptive or maladaptive. Pharmacological modification of gene expression in the hypertrophied heart may, therefore, be an attractive approach to prevent or even treat maladaptive hypertrophy and heart failure. Calcineurin is a serine-threonine phosphatase that is activated by sustained increases in [Ca2+]i in cardiomyocytes. Although it has been firmly established that calcineurin plays a critical role in the development of cardiac hypertrophy, the question of whether calcineurin activation serves an adaptive or maladaptive role is still unresolved. An answer to this question is crucial if calcineurin is to be developed as a drug target. The authors propose that calcineurin acts as a double-edged sword; excessive activation of calcineurin is maladaptive, its activation at endogenous levels and at specific subcellular microdomains, however, promotes adaptation. Calcineurin itself may, therefore, not be a convenient target for drug development. However, because maladaptive hypertrophy is ultimately a transcriptional disorder, definition of the transcriptional programme activated by distinct calcineurin activation levels may permit identification of novel, attractive drug targets.
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Affiliation(s)
- Beate Fiedler
- Hanover Medical School, Department of Cardiology and Angiology, 30625 Hanover, Germany
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48
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Mishima M, Wakabayashi S, Kojima C. Solution Structure of the Cytoplasmic Region of Na+/H+ Exchanger 1 Complexed with Essential Cofactor Calcineurin B Homologous Protein 1. J Biol Chem 2007; 282:2741-51. [PMID: 17050540 DOI: 10.1074/jbc.m604092200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Na+/H+ exchanger 1 (NHE1) regulates intracellular pH, Na+ content, and cell volume. Calcineurin B homologous protein 1 (CHP1) serves as an essential cofactor that facilitates NHE1 exchange activity under physiological conditions by direct binding to the cytoplasmic juxtamembrane region of NHE1. Here we describe the solution structure of the cytoplasmic juxtamembrane region of NHE1 complexed with CHP1. The region of NHE1 forms an amphipathic helix, which is induced by CHP1 binding, and CHP1 possesses a large hydrophobic cleft formed by EF-hand helices. The apolar side of the NHE1 helix participates in extensive hydrophobic interactions with the cleft of CHP1. We suggest that helix formation of the cytoplasmic region of NHE1 by CHP1 is a prerequisite for generating the active form of NHE1. The molecular recognition detailed in this study also provides novel insight into the target binding mechanism of EF-hand proteins.
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Affiliation(s)
- Masaki Mishima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
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49
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Friedrich ML, Cui M, Hernandez JB, Weist BM, Andersen HM, Zhang X, Huang L, Walsh CM. Modulation of DRAK2 autophosphorylation by antigen receptor signaling in primary lymphocytes. J Biol Chem 2006; 282:4573-4584. [PMID: 17182616 DOI: 10.1074/jbc.m606675200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Death-associated protein-related apoptotic kinase-2 (DRAK2), a member of the death-associated protein-like family of serine/threonine kinases, is highly expressed in lymphoid organs and is a negative regulator of T cell activation. To investigate the regulation of DRAK2 activity in primary lymphocytes, we employed mass spectrometry to identify sites of autophosphorylation on DRAK2. These studies have revealed a key site of autophosphorylation on serine 12. Using a phospho-specific antibody to detect Ser(12) phosphorylation, we found that autophosphorylation is induced by antigen receptor stimulation in T and B cells. In Jurkat T cells, resting B cells and thymocytes, DRAK2 was hypophosphorylated on Ser(12) but rapidly phosphorylated with antigen receptor ligation. This increase in phosphorylation was dependent on intracellular calcium mobilization, because BAPTA-AM blocked DRAK2 kinase activity, whereas the SERCA inhibitor thapsigargin promoted Ser(12) phosphorylation. Our results show that DRAK2 kinase activity is regulated in a calcium-dependent manner and that Ser(12) phosphorylation is necessary for optimal suppression of T cell activation by this kinase, suggesting a potential feedback loop may act to modulate the activity of this kinase following antigen receptor signaling.
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Affiliation(s)
- Monica L Friedrich
- Center for Immunology and Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, California 92697
| | - Meng Cui
- Departments of Physiology & Biophysics and Developmental & Cell Biology, University of California, Irvine, Irvine, California 92697
| | - Jeniffer B Hernandez
- Center for Immunology and Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, California 92697
| | - Brian M Weist
- Center for Immunology and Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, California 92697
| | - Hilde-Marie Andersen
- Center for Immunology and Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, California 92697
| | - Xiaowu Zhang
- Cell Signaling Technology, Inc., Danvers, Massachusetts 01923
| | - Lan Huang
- Departments of Physiology & Biophysics and Developmental & Cell Biology, University of California, Irvine, Irvine, California 92697; Cancer Research Institute, University of California, Irvine, Irvine, California 92697 and.
| | - Craig M Walsh
- Center for Immunology and Department of Molecular Biology & Biochemistry, University of California, Irvine, Irvine, California 92697; Cancer Research Institute, University of California, Irvine, Irvine, California 92697 and.
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50
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Kuwahara H, Nakamura N, Kanazawa H. Nuclear Localization of the Serine/Threonine Kinase DRAK2 Is Involved in UV-Induced Apoptosis. Biol Pharm Bull 2006; 29:225-33. [PMID: 16462023 DOI: 10.1248/bpb.29.225] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
DAP kinase-related apoptosis-inducing kinase 2 (DRAK2), a member of the DAP kinase family, is a serine/threonine kinase capable of inducing apoptosis. Here we studied the relationship between DRAK2 intracellular localization and apoptosis, and found that UV light acts as a stimulus for apoptosis induced by DRAK2. The intracellular location of DRAK2 depended on the cell line: DRAK2 was found primarily in the nuclei of NRK, NIH3T3, and Caco-2 cells while it was present primarily in the cytoplasm of ACL-15, HeLa, and WI-38 cells. Overexpression of Myc-tagged DRAK2 led to apoptosis-like cell death in NRK cells, but not in ACL-15 cells. A GFP fusion protein of DRAK2 was spontaneously localized to the nucleus of ACL-15 cells and resulted in cell death. Nuclear localization and cell death were also observed with DRAK2(1-293) fused to the NLS of SV40 but not with DRAK2(1-293) alone. These results suggested that nuclear accumulation of DRAK2 and the resulting increase in the endogenous level of its kinase activity are required for cell death. UV irradiation caused nuclear accumulation of endogenous DRAK2 in ACL-15 cells, which was followed by apoptosis-like cell death. Knockdown of DRAK2 expression by siRNA partially suppressed UV-induced apoptosis. These results suggest that DRAK2 plays a role in UV induced apoptosis.
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Affiliation(s)
- Hiroshi Kuwahara
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
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