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Kumar P, Bhardwaj A, Mukherjee B, Joshi R, Giri R. Coronaviruses spike glycoprotein endodomains: The sequence and structure-based comprehensive study. Protein Sci 2023; 32:e4804. [PMID: 37833239 PMCID: PMC10599102 DOI: 10.1002/pro.4804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/04/2023] [Accepted: 10/08/2023] [Indexed: 10/15/2023]
Abstract
Any protein's flexibility or region makes it available to interact with many biomolecules in the cell. Specifically, such interactions in viruses help them to perform more functions despite having a smaller genome. Therefore, these flexible regions can be exciting and essential targets to be explored for their role in pathogenicity and therapeutic developments as they achieve essential interactions. In the continuation with our previous study on disordered analysis of SARS-CoV-2 spike protein's cytoplasmic tail (CTR), or endodomain, here we have explored the endodomain's disordered potential of six other coronaviruses using multiple bioinformatics approaches and molecular dynamics simulations. Based on the comprehensive analysis of its sequence and structural composition, we report the varying disorder propensity in endodomains of spike proteins of coronaviruses. The observations of this study may help to understand the importance of spike glycoprotein endodomain and creating therapeutic interventions against them.
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Affiliation(s)
- Prateek Kumar
- School of Biosciences and BioengineeringIndian Institute of Technology MandiMandiHimachal PradeshIndia
| | - Aparna Bhardwaj
- School of Biosciences and BioengineeringIndian Institute of Technology MandiMandiHimachal PradeshIndia
| | - Bodhidipra Mukherjee
- School of Biosciences and BioengineeringIndian Institute of Technology MandiMandiHimachal PradeshIndia
| | - Richa Joshi
- School of Biosciences and BioengineeringIndian Institute of Technology MandiMandiHimachal PradeshIndia
| | - Rajanish Giri
- School of Biosciences and BioengineeringIndian Institute of Technology MandiMandiHimachal PradeshIndia
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Zhang W, Fan W, Guo J, Wang X. Osmotic stress activates RIPK3/MLKL-mediated necroptosis by increasing cytosolic pH through a plasma membrane Na +/H + exchanger. Sci Signal 2022; 15:eabn5881. [PMID: 35580168 DOI: 10.1126/scisignal.abn5881] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Necroptosis is a form of cell death triggered by stimuli such as the tumor necrosis factor family of cytokines, which induce necrotic cell death through the RIPK1-RIPK3-MLKL pathway. We report here that necroptosis is also activated by extracellular osmotic stresses. Unlike the previously identified inducers of necroptosis, osmotic stress stimulated necroptosis through the direct activation of the kinase activity of RIPK3 by an increase in cytosolic pH mediated by the Na+/H+ exchanger SLC9A1. Knockout, knockdown, or chemical inhibition of SLC9A1 blocked necroptosis induced by osmotic stresses. Moreover, setting intracellular pH at above-physiological values directly activated RIPK3 and necroptosis. The activation of RIPK3 by osmotic stresses did not require its RHIM domain, the protein-interacting domain required for the activation of RIPK3 when cells respond to other previously identified necroptotic stimuli. These results thus delineate a pathway that activates necroptosis in response to osmotic stresses.
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Affiliation(s)
- Wenbin Zhang
- School of Life Sciences, Peking University, Beijing 100871, China.,National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100084, China
| | - Weiliang Fan
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100084, China
| | - Jia Guo
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100084, China
| | - Xiaodong Wang
- National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100084, China
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Flatt JF, Bruce LJ. The Molecular Basis for Altered Cation Permeability in Hereditary Stomatocytic Human Red Blood Cells. Front Physiol 2018; 9:367. [PMID: 29713289 PMCID: PMC5911802 DOI: 10.3389/fphys.2018.00367] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 03/27/2018] [Indexed: 11/20/2022] Open
Abstract
Normal human RBCs have a very low basal permeability (leak) to cations, which is continuously corrected by the Na,K-ATPase. The leak is temperature-dependent, and this temperature dependence has been evaluated in the presence of inhibitors to exclude the activity of the Na,K-ATPase and NaK2Cl transporter. The severity of the RBC cation leak is altered in various conditions, most notably the hereditary stomatocytosis group of conditions. Pedigrees within this group have been classified into distinct phenotypes according to various factors, including the severity and temperature-dependence of the cation leak. As recent breakthroughs have provided more information regarding the molecular basis of hereditary stomatocytosis, it has become clear that these phenotypes elegantly segregate with distinct genetic backgrounds. The cryohydrocytosis phenotype, including South-east Asian Ovalocytosis, results from mutations in SLC4A1, and the very rare condition, stomatin-deficient cryohydrocytosis, is caused by mutations in SLC2A1. Mutations in RHAG cause the very leaky condition over-hydrated stomatocytosis, and mutations in ABCB6 result in familial pseudohyperkalemia. All of the above are large multi-spanning membrane proteins and the mutations may either modify the structure of these proteins, resulting in formation of a cation pore, or otherwise disrupt the membrane to allow unregulated cation movement across the membrane. More recently mutations have been found in two RBC cation channels, PIEZO1 and KCNN4, which result in dehydrated stomatocytosis. These mutations alter the activation and deactivation kinetics of these channels, leading to increased opening and allowing greater cation fluxes than in wild type.
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Affiliation(s)
- Joanna F Flatt
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, United Kingdom
| | - Lesley J Bruce
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, United Kingdom
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5
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Hendus-Altenburger R, Pedraz-Cuesta E, Olesen CW, Papaleo E, Schnell JA, Hopper JTS, Robinson CV, Pedersen SF, Kragelund BB. The human Na(+)/H(+) exchanger 1 is a membrane scaffold protein for extracellular signal-regulated kinase 2. BMC Biol 2016; 14:31. [PMID: 27083547 PMCID: PMC4833948 DOI: 10.1186/s12915-016-0252-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/29/2016] [Indexed: 11/22/2022] Open
Abstract
Background Extracellular signal-regulated kinase 2 (ERK2) is an S/T kinase with more than 200 known substrates, and with critical roles in regulation of cell growth and differentiation and currently no membrane proteins have been linked to ERK2 scaffolding. Methods and results Here, we identify the human Na+/H+ exchanger 1 (hNHE1) as a membrane scaffold protein for ERK2 and show direct hNHE1-ERK1/2 interaction in cellular contexts. Using nuclear magnetic resonance (NMR) spectroscopy and immunofluorescence analysis we demonstrate that ERK2 scaffolding by hNHE1 occurs by one of three D-domains and by two non-canonical F-sites located in the disordered intracellular tail of hNHE1, mutation of which reduced cellular hNHE1-ERK1/2 co-localization, as well as reduced cellular ERK1/2 activation. Time-resolved NMR spectroscopy revealed that ERK2 phosphorylated the disordered tail of hNHE1 at six sites in vitro, in a distinct temporal order, with the phosphorylation rates at the individual sites being modulated by the docking sites in a distant dependent manner. Conclusions This work characterizes a new type of scaffolding complex, which we term a “shuffle complex”, between the disordered hNHE1-tail and ERK2, and provides a molecular mechanism for the important ERK2 scaffolding function of the membrane protein hNHE1, which regulates the phosphorylation of both hNHE1 and ERK2. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0252-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ruth Hendus-Altenburger
- Cell and Developmental Biology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark.,Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen N, Denmark
| | - Elena Pedraz-Cuesta
- Cell and Developmental Biology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Christina W Olesen
- Cell and Developmental Biology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark
| | - Elena Papaleo
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen N, Denmark
| | - Jeff A Schnell
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen N, Denmark
| | - Jonathan T S Hopper
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
| | - Stine F Pedersen
- Cell and Developmental Biology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen Ø, Denmark.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, Copenhagen N, Denmark.
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6
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Alonso-Morales A, González-López L, Cázares-Raga FE, Cortés-Martínez L, Torres-Monzón JA, Gallegos-Pérez JL, Rodríguez MH, James AA, Hernández-Hernández FDLC. Protein phosphorylation during Plasmodium berghei gametogenesis. Exp Parasitol 2015; 156:49-60. [PMID: 26008612 DOI: 10.1016/j.exppara.2015.05.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 05/08/2015] [Accepted: 05/18/2015] [Indexed: 10/23/2022]
Abstract
Plasmodium gametogenesis within the mosquito midgut is a complex differentiation process involving signaling mediated by phosphorylation, which modulate metabolic routes and protein synthesis required to complete this development. However, the mechanisms leading to gametogenesis activation are poorly understood. We analyzed protein phosphorylation during Plasmodium berghei gametogenesis in vitro in serum-free medium using bidimensional electrophoresis (2-DE) combined with immunoblotting (IB) and antibodies specific to phosphorylated serine, threonine and tyrosine. Approximately 75 protein exhibited phosphorylation changes, of which 23 were identified by mass spectrometry. These included components of the cytoskeleton, heat shock proteins, and proteins involved in DNA synthesis and signaling pathways among others. Novel phosphorylation events support a role for these proteins during gametogenesis. The phosphorylation sites of six of the identified proteins, HSP70, WD40 repeat protein msi1, enolase, actin-1 and two isoforms of large subunit of ribonucleoside reductase were investigated using TiO2 phosphopeptides enrichment and tandem mass spectrometry. In addition, transient exposure to hydroxyurea, an inhibitor of ribonucleoside reductase, impaired male gametocytes exflagellation in a dose-dependent manner, and provides a resource for functional studies.
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Affiliation(s)
- Alberto Alonso-Morales
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Avenida Instituto Politécnico Nacional # 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, C.P. 07360, México, D.F., México
| | - Lorena González-López
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Avenida Instituto Politécnico Nacional # 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, C.P. 07360, México, D.F., México
| | - Febe Elena Cázares-Raga
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Avenida Instituto Politécnico Nacional # 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, C.P. 07360, México, D.F., México
| | - Leticia Cortés-Martínez
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Avenida Instituto Politécnico Nacional # 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, C.P. 07360, México, D.F., México
| | - Jorge Aurelio Torres-Monzón
- Centro Regional de Investigación en Salud Pública, Instituto Nacional de Salud Pública, Avenida 19 Poniente esquina 4a Norte s/n, Colonia Centro, C.P. 62100 Tapachula, Chiapas, Mexico
| | | | - Mario Henry Rodríguez
- Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Avenida Universidad # 655, Colonia Santa María Ahuacatitlán, C.P. 62100, Cuernavaca, Morelos, México
| | - Anthony A James
- Departments of Molecular Biology and Biochemistry, and Microbiology and Molecular Genetics, University of California, Irvine, CA 92697, USA
| | - Fidel de la Cruz Hernández-Hernández
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Avenida Instituto Politécnico Nacional # 2508, Colonia San Pedro Zacatenco, Delegación Gustavo A. Madero, C.P. 07360, México, D.F., México.
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7
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Herren AW, Weber DM, Rigor RR, Margulies KB, Phinney BS, Bers DM. CaMKII Phosphorylation of Na(V)1.5: Novel in Vitro Sites Identified by Mass Spectrometry and Reduced S516 Phosphorylation in Human Heart Failure. J Proteome Res 2015; 14:2298-311. [PMID: 25815641 DOI: 10.1021/acs.jproteome.5b00107] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cardiac voltage-gated sodium channel, Na(V)1.5, drives the upstroke of the cardiac action potential and is a critical determinant of myocyte excitability. Recently, calcium (Ca(2+))/calmodulin(CaM)-dependent protein kinase II (CaMKII) has emerged as a critical regulator of Na(V)1.5 function through phosphorylation of multiple residues including S516, T594, and S571, and these phosphorylation events may be important for the genesis of acquired arrhythmias, which occur in heart failure. However, phosphorylation of full-length human Na(V)1.5 has not been systematically analyzed and Na(V)1.5 phosphorylation in human heart failure is incompletely understood. In the present study, we used label-free mass spectrometry to assess phosphorylation of human Na(V)1.5 purified from HEK293 cells with full coverage of phosphorylatable sites and identified 23 sites that were phosphorylated by CaMKII in vitro. We confirmed phosphorylation of S516 and S571 by LC-MS/MS and found a decrease in S516 phosphorylation in human heart failure, using a novel phospho-specific antibody. This work furthers our understanding of the phosphorylation of Na(V)1.5 by CaMKII under normal and disease conditions, provides novel CaMKII target sites for functional validation, and provides the first phospho-proteomic map of full-length human Na(V)1.5.
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Affiliation(s)
- Anthony W Herren
- †Department of Pharmacology, University of California Davis, Genome Building 3513, Davis, California 95616, United States
| | - Darren M Weber
- §UC Davis Genome Center, University of California Davis, 451 Health Science Drive, Davis, California 95616, United States
| | - Robert R Rigor
- †Department of Pharmacology, University of California Davis, Genome Building 3513, Davis, California 95616, United States
| | - Kenneth B Margulies
- ∥Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, Philadelphia, Pennsylvania 19104, United States
| | - Brett S Phinney
- §UC Davis Genome Center, University of California Davis, 451 Health Science Drive, Davis, California 95616, United States
| | - Donald M Bers
- †Department of Pharmacology, University of California Davis, Genome Building 3513, Davis, California 95616, United States
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Hewezi T, Juvale PS, Piya S, Maier TR, Rambani A, Rice JH, Mitchum MG, Davis EL, Hussey RS, Baum TJ. The cyst nematode effector protein 10A07 targets and recruits host posttranslational machinery to mediate its nuclear trafficking and to promote parasitism in Arabidopsis. THE PLANT CELL 2015; 27:891-907. [PMID: 25715285 PMCID: PMC4558665 DOI: 10.1105/tpc.114.135327] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 01/29/2015] [Accepted: 02/10/2015] [Indexed: 05/18/2023]
Abstract
Plant-parasitic cyst nematodes synthesize and secrete effector proteins that are essential for parasitism. One such protein is the 10A07 effector from the sugar beet cyst nematode, Heterodera schachtii, which is exclusively expressed in the nematode dorsal gland cell during all nematode parasitic stages. Overexpression of H. schachtii 10A07 in Arabidopsis thaliana produced a hypersusceptible phenotype in response to H. schachtii infection along with developmental changes reminiscent of auxin effects. The 10A07 protein physically associates with a plant kinase and the IAA16 transcription factor in the cytoplasm and nucleus, respectively. The interacting plant kinase (IPK) phosphorylates 10A07 at Ser-144 and Ser-231 and mediates its trafficking from the cytoplasm to the nucleus. Translocation to the nucleus is phosphorylation dependent since substitution of Ser-144 and Ser-231 by alanine resulted in exclusive cytoplasmic accumulation of 10A07. IPK and IAA16 are highly upregulated in the nematode-induced syncytium (feeding cells), and deliberate manipulations of their expression significantly alter plant susceptibility to H. schachtii in an additive fashion. An inactive variant of IPK functioned antagonistically to the wild-type IPK and caused a dominant-negative phenotype of reduced plant susceptibility. Thus, exploitation of host processes to the advantage of the parasites is one mechanism by which cyst nematodes promote parasitism of host plants.
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Affiliation(s)
- Tarek Hewezi
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee 37996
| | - Parijat S Juvale
- Department of Plant Pathology, Iowa State University, Ames, Iowa 50011
| | - Sarbottam Piya
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee 37996
| | - Tom R Maier
- Department of Plant Pathology, Iowa State University, Ames, Iowa 50011
| | - Aditi Rambani
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee 37996
| | - J Hollis Rice
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee 37996
| | - Melissa G Mitchum
- Division of Plant Sciences and Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211
| | - Eric L Davis
- North Carolina State University, Raleigh, North Carolina 27695
| | - Richard S Hussey
- Department of Plant Pathology, University of Georgia, Athens, Georgia 30602
| | - Thomas J Baum
- Department of Plant Pathology, Iowa State University, Ames, Iowa 50011
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Chen B, Pan W, Zhang L, Liu J, Ouyang H, Nie Q, Zhang X. NHE1 gene associated with avian leukosis virus subgroup J infection in chicken. Mol Biol Rep 2014; 41:6519-24. [PMID: 24985980 DOI: 10.1007/s11033-014-3535-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 06/19/2014] [Indexed: 11/29/2022]
Abstract
As a kind of binding protein, the type 1 Na(+)/H(+) exchanger (NHE1) is a receptor for the highly pathogenic Avian leukosis viruses-J subgroup (ALV-J) in chicken. In order to investigate the potential effect of chicken NHE1 gene on leukosis, we compared its expression between ALV-J-affected and -unaffected chicken, screened variations across the whole gene, and then performed association analysis with ALV-J affected/unaffected trait in three un-related chicken populations. We found that the NHE1 gene expressed in four immune tissues including spleen, bursa fabricius, liver, and thymus, and its expression was significantly up-regulated in liver and thymus of ALV-J-affected chickens (with leukosis phenotype) compared to -unaffected ones (ALV-J-negative controls). Thirty-six single nucleotide polymorphisms (SNP) were identified in a 6,105 bp region of the chicken NHE1 gene, giving rise to every 170 bp per SNP. Two SNP of g.4405A>G and g.5886C>G were genotyped with PCR-RFLP method. Results showed that g.4405A>G was significantly associated (P < 0.05) with ALV-J infection in all of the three chicken populations, including White Recessive Rock (WRR), Dwarf Yellow (DY) and Shiki Yellow (SY), while g.5886C>G was significantly associated (P < 0.05) with ALV-J infection in SY. These results indicated that the NHE1 gene was related to ALV-J infection in chicken.
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Affiliation(s)
- Biao Chen
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China
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Lakshmanan A, Doseff AI, Ringel MD, Saji M, Rousset B, Zhang X, Jhiang SM. Apigenin in combination with Akt inhibition significantly enhances thyrotropin-stimulated radioiodide accumulation in thyroid cells. Thyroid 2014; 24:878-87. [PMID: 24400871 PMCID: PMC4026312 DOI: 10.1089/thy.2013.0614] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND Selectively increased radioiodine accumulation in thyroid cells by thyrotropin (TSH) allows targeted treatment of thyroid cancer. However, the extent of TSH-stimulated radioiodine accumulation in some thyroid tumors is not sufficient to confer therapeutic efficacy. Hence, it is of clinical importance to identify novel strategies to selectively further enhance TSH-stimulated thyroidal radioiodine accumulation. METHODS PCCl3 rat thyroid cells, PCCl3 cells overexpressing BRAF(V600E), or primary cultured tumor cells from a thyroid cancer mouse model, under TSH stimulation were treated with various reagents for 24 hours. Cells were then subjected to radioactive iodide uptake, kinetics, efflux assays, and protein extraction followed by Western blotting against selected antibodies. RESULTS We previously reported that Akt inhibition increased radioiodine accumulation in thyroid cells under chronic TSH stimulation. Here, we identified Apigenin, a plant-derived flavonoid, as a reagent to further enhance the iodide influx rate increased by Akt inhibition in thyroid cells under acute TSH stimulation. Akt inhibition is permissive for Apigenin's action, as Apigenin alone had little effect. This action of Apigenin requires p38 MAPK activity but not PKC-δ. The increase in radioiodide accumulation by Apigenin with Akt inhibition was also observed in thyroid cells expressing BRAF(V600E) and in primary cultured thyroid tumor cells from TRβ(PV/PV) mice. CONCLUSION Taken together, Apigenin may serve as a dietary supplement in combination with Akt inhibitors to enhance therapeutic efficacy of radioiodine for thyroid cancer.
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Affiliation(s)
- Aparna Lakshmanan
- Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, Ohio
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Andrea I. Doseff
- Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, Ohio
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio
| | - Matthew D. Ringel
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Motoyasu Saji
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio
| | - Bernard Rousset
- Cancer Research Center of Lyon (INSERM U1052/CNRS UMR 5286), Federation of Health Research of Eastern Lyon (CNRS UMS 3453/INSERM US7 Louis Léopold Oller), Lyon, France
| | - Xiaoli Zhang
- Center for Biostatistics, The Ohio State University, Columbus, Ohio
| | - Sissy M. Jhiang
- Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, Ohio
- Department of Internal Medicine, The Ohio State University, Columbus, Ohio
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11
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Hendus-Altenburger R, Kragelund BB, Pedersen SF. Structural dynamics and regulation of the mammalian SLC9A family of Na⁺/H⁺ exchangers. CURRENT TOPICS IN MEMBRANES 2014; 73:69-148. [PMID: 24745981 DOI: 10.1016/b978-0-12-800223-0.00002-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mammalian Na⁺/H⁺ exchangers of the SLC9A family are widely expressed and involved in numerous essential physiological processes. Their primary function is to mediate the 1:1 exchange of Na⁺ for H⁺ across the membrane in which they reside, and they play central roles in regulation of body, cellular, and organellar pH. Their function is tightly regulated through mechanisms involving interactions with multiple protein and lipid-binding partners, phosphorylations, and other posttranslational modifications. Biochemical and mutational analyses indicate that the SLC9As have a short intracellular N-terminus, 12 transmembrane (TM) helices necessary and sufficient for ion transport, and a C-terminal cytoplasmic tail region with essential regulatory roles. No high-resolution structures of the SLC9As exist; however, models based on crystal structures of the bacterial NhaAs support the 12 TM organization and suggest that TMIV and XI may form a central part of the ion-translocation pathway, whereas pH sensing may involve TMII, TMIX, and several intracellular loops. Similar to most ion transporters studied, SLC9As likely exist as coupled dimers in the membrane, and this appears to be important for the well-studied cooperativity of H⁺ binding. The aim of this work is to summarize and critically discuss the currently available evidence on the structural dynamics, regulation, and binding partner interactions of SLC9As, focusing in particular on the most widely studied isoform, SLC9A1/NHE1. Further, novel bioinformatic and structural analyses are provided that to some extent challenge the existing paradigm on how ions are transported by mammalian SLC9As.
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Affiliation(s)
- Ruth Hendus-Altenburger
- Section for Biomolecular Sciences, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Section for Cell and Developmental Biology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B Kragelund
- Section for Biomolecular Sciences, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell and Developmental Biology, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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12
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Aravena C, Beltrán AR, Cornejo M, Torres V, Díaz ES, Guzmán-Gutiérrez E, Pardo F, Leiva A, Sobrevia L, Ramírez MA. Potential role of sodium-proton exchangers in the low concentration arsenic trioxide-increased intracellular pH and cell proliferation. PLoS One 2012; 7:e51451. [PMID: 23236503 PMCID: PMC3516555 DOI: 10.1371/journal.pone.0051451] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 11/01/2012] [Indexed: 01/01/2023] Open
Abstract
Arsenic main inorganic compound is arsenic trioxide (ATO) presented in solution mainly as arsenite. ATO increases intracellular pH (pHi), cell proliferation and tumor growth. Sodium-proton exchangers (NHEs) modulate the pHi, with NHE1 playing significant roles. Whether ATO-increased cell proliferation results from altered NHEs expression and activity is unknown. We hypothesize that ATO increases cell proliferation by altering pHi due to increased NHEs-like transport activity. Madin-Darby canine kidney (MDCK) cells grown in 5 mmol/L D-glucose-containing DMEM were exposed to ATO (0.05, 0.5 or 5 µmol/L, 0–48 hours) in the absence or presence of 5-N,N-hexamethylene amiloride (HMA, 5–100 µmol/L, NHEs inhibitor), PD-98059 (30 µmol/L, MAPK1/2 inhibitor), Gö6976 (10 µmol/L, PKCα, βI and μ inhibitor), or Schering 28080 (10 µmol/L, H+/K+ATPase inhibitor) plus concanamycin (0.1 µmol/L, V type ATPases inhibitor). Incorporation of [3H]thymidine was used to estimate cell proliferation, and counting cells with a hemocytometer to determine the cell number. The pHi was measured by fluorometry in 2,7-bicarboxyethyl-5,6-carboxyfluorescein loaded cells. The Na+-dependent HMA-sensitive NHEs-like mediated proton transport kinetics, NHE1 protein abundance in the total, cytoplasm and plasma membrane protein fractions, and phosphorylated and total p42/44 mitogen-activated protein kinases (p42/44mapk) were also determined. Lowest ATO (0.05 µmol/L, ∼0.01 ppm) used in this study increased cell proliferation, pHi, NHEs-like transport and plasma membrane NHE1 protein abundance, effects blocked by HMA, PD-98059 or Gö6976. Cell-buffering capacity did not change by ATO. The results show that a low ATO concentration increases MDCK cells proliferation by NHEs (probably NHE1)-like transport dependent-increased pHi requiring p42/44mapk and PKCα, βI and/or μ activity. This finding could be crucial in diseases where uncontrolled cell growth occurs, such as tumor growth, and in circumstances where ATO, likely arsenite, is available at the drinking-water at these levels.
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Affiliation(s)
- Carmen Aravena
- Cellular Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta, Chile
| | - Ana R. Beltrán
- Cellular Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta, Chile
- Department of Education, Faculty of Education, Universidad de Antofagasta, Antofagasta, Chile
| | - Marcelo Cornejo
- Cellular Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta, Chile
| | - Viviana Torres
- Advanced Microscopy Centre (CMA Bío-Bío), Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Emilce S. Díaz
- Cellular Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta, Chile
| | - Enrique Guzmán-Gutiérrez
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fabián Pardo
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Andrea Leiva
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail: (MAR); (LS)
| | - Marco A. Ramírez
- Cellular Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta, Chile
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail: (MAR); (LS)
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