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Papp F, Lomash S, Szilagyi O, Babikow E, Smith J, Chang TH, Bahamonde MI, Toombes GES, Swartz KJ. TMEM266 is a functional voltage sensor regulated by extracellular Zn 2. eLife 2019; 8:42372. [PMID: 30810529 PMCID: PMC6392501 DOI: 10.7554/elife.42372] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/13/2019] [Indexed: 12/15/2022] Open
Abstract
Voltage-activated ion channels contain S1-S4 domains that sense membrane voltage and control opening of ion-selective pores, a mechanism that is crucial for electrical signaling. Related S1-S4 domains have been identified in voltage-sensitive phosphatases and voltage-activated proton channels, both of which lack associated pore domains. hTMEM266 is a protein of unknown function that is predicted to contain an S1-S4 domain, along with partially structured cytoplasmic termini. Here we show that hTMEM266 forms oligomers, undergoes both rapid (µs) and slow (ms) structural rearrangements in response to changes in voltage, and contains a Zn2+ binding site that can regulate the slow conformational transition. Our results demonstrate that the S1-S4 domain in hTMEM266 is a functional voltage sensor, motivating future studies to identify cellular processes that may be regulated by the protein. The ability of hTMEM266 to respond to voltage on the µs timescale may be advantageous for designing new genetically encoded voltage indicators.
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Affiliation(s)
- Ferenc Papp
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States.,MTA-DE-NAP B Ion Channel Structure-Function Research Group, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Suvendu Lomash
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Orsolya Szilagyi
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Erika Babikow
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Jaime Smith
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Tsg-Hui Chang
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Maria Isabel Bahamonde
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Gilman Ewan Stephen Toombes
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Kenton Jon Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
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Bahamonde MI, Serra SA, Drechsel O, Rahman R, Marcé-Grau A, Prieto M, Ossowski S, Macaya A, Fernández-Fernández JM. A Single Amino Acid Deletion (ΔF1502) in the S6 Segment of CaV2.1 Domain III Associated with Congenital Ataxia Increases Channel Activity and Promotes Ca2+ Influx. PLoS One 2015; 10:e0146035. [PMID: 26716990 PMCID: PMC4696675 DOI: 10.1371/journal.pone.0146035] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/11/2015] [Indexed: 02/07/2023] Open
Abstract
Mutations in the CACNA1A gene, encoding the pore-forming CaV2.1 (P/Q-type) channel α1A subunit, result in heterogeneous human neurological disorders, including familial and sporadic hemiplegic migraine along with episodic and progressive forms of ataxia. Hemiplegic Migraine (HM) mutations induce gain-of-channel function, mainly by shifting channel activation to lower voltages, whereas ataxia mutations mostly produce loss-of-channel function. However, some HM-linked gain-of-function mutations are also associated to congenital ataxia and/or cerebellar atrophy, including the deletion of a highly conserved phenylalanine located at the S6 pore region of α1A domain III (ΔF1502). Functional studies of ΔF1502 CaV2.1 channels, expressed in Xenopus oocytes, using the non-physiological Ba2+ as the charge carrier have only revealed discrete alterations in channel function of unclear pathophysiological relevance. Here, we report a second case of congenital ataxia linked to the ΔF1502 α1A mutation, detected by whole-exome sequencing, and analyze its functional consequences on CaV2.1 human channels heterologously expressed in mammalian tsA-201 HEK cells, using the physiological permeant ion Ca2+. ΔF1502 strongly decreases the voltage threshold for channel activation (by ~ 21 mV), allowing significantly higher Ca2+ current densities in a range of depolarized voltages with physiological relevance in neurons, even though maximal Ca2+ current density through ΔF1502 CaV2.1 channels is 60% lower than through wild-type channels. ΔF1502 accelerates activation kinetics and slows deactivation kinetics of CaV2.1 within a wide range of voltage depolarization. ΔF1502 also slowed CaV2.1 inactivation kinetic and shifted the inactivation curve to hyperpolarized potentials (by ~ 28 mV). ΔF1502 effects on CaV2.1 activation and deactivation properties seem to be of high physiological relevance. Thus, ΔF1502 strongly promotes Ca2+ influx in response to either single or trains of action potential-like waveforms of different durations. Our observations support a causative role of gain-of-function CaV2.1 mutations in congenital ataxia, a neurodevelopmental disorder at the severe-most end of CACNA1A-associated phenotypic spectrum.
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Affiliation(s)
- Maria Isabel Bahamonde
- Laboratori de Fisiologia Molecular i Canalopaties, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Selma Angèlica Serra
- Laboratori de Fisiologia Molecular i Canalopaties, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Oliver Drechsel
- Genomic and Epigenomic Variation in Disease Group, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Rubayte Rahman
- Genomic and Epigenomic Variation in Disease Group, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Anna Marcé-Grau
- Pediatric Neurology Research Group, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Marta Prieto
- Laboratori de Fisiologia Molecular i Canalopaties, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Stephan Ossowski
- Genomic and Epigenomic Variation in Disease Group, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Alfons Macaya
- Pediatric Neurology Research Group, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - José M. Fernández-Fernández
- Laboratori de Fisiologia Molecular i Canalopaties, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
- * E-mail:
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Garcia A, Ortiz S, Iribarren C, Bahamonde MI, Solari A. Congenital co-infection with different Trypanosoma cruzi lineages. Parasitol Int 2014; 63:138-139. [PMID: 24422218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Variability of mixed Trypanosoma cruzi congenital infection in Chile in twenty one congenital samples of Chagas disease is reported. Recognition of infecting strains was performed by minicircle hybridization tests. Seven newborns with double infection were found. Trypanosoma cruzi TcII and TcV lineages were the most frequent in single and mixed infections. With these results we pretend to understand the epidemiological significance of the T. cruzi lineages for which the placenta does not seem to represent an actual barrier in congenital infections.
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Diaz M, Bahamonde MI, Lock H, Muñoz FJ, Hardy SP, Posas F, Valverde MA. Okadaic acid-sensitive activation of Maxi Cl(-) channels by triphenylethylene antioestrogens in C1300 mouse neuroblastoma cells. J Physiol 2001; 536:79-88. [PMID: 11579158 PMCID: PMC2278843 DOI: 10.1111/j.1469-7793.2001.00079.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
1. The regulation of Maxi Cl(-) channels by 17beta-oestradiol and non-steroidal triphenylethylene antioestrogens represents a rapid, non-classical effect of these compounds. In the present study we have investigated the signalling pathways used for the regulation of Maxi Cl(-) channel activity by oestrogens and antioestrogens in C1300 neuroblastoma cells. 2. Whole-cell Maxi Cl(-) currents were readily and reversibly activated by tamoxifen, toremifene and the membrane-impermeant ethyl-bromide tamoxifen, only when applied to the extracellular medium. 3. Pre-treatment of C1300 cells with oestrogen or cAMP prevented the antioestrogen-induced activation of Maxi Cl(-) channels. The inhibitory effect of 17beta-oestradiol and cAMP was abolished by the kinase inhibitor staurosporine. 4. Current activation was unaffected by the removal of intracellular Ca(2+) and Mg(2+), but was completely abolished in the presence of okadaic acid. These results are consistent with the participation of an okadaic acid-sensitive serine/threonine protein phosphatase in the activation of Maxi Cl(-) channels. However, neither oestrogen or antioestrogen treatment modified the total activity of the two major serine/threonine phosphatases, PP1 and PP2A, in C1300 cells. 5. Although the role of these Maxi Cl(-) channels remains unknown, our findings suggest strongly that their modulation by oestrogens and antioestrogens is linked to intracellular signalling pathways.
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Affiliation(s)
- M Diaz
- Departamento de Biología Animal, Universidad de la Laguna, Tenerife, Spain
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Lorca M, García A, Bahamonde MI, Fritz A, Tassara R. [Serological certification of the interruption of the vectorial transmission of Chagas disease in Chile]. Rev Med Chil 2001; 129:264-9. [PMID: 11372293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
BACKGROUND In 1999 an International Commission of Experts evaluated the sanitary interventions that started in 1980 to eliminate Triatoma infestans, the biological vector of Chagas disease, to certify if the conditions needed to interrupt the transmission, were achieved. AIM To report the data used by the International certification commission to certify the interruption of vectorial transmission of Chagas disease in Chile. MATERIAL AND METHODS A comparative evaluation of the prevalence of Trypanosoma cruzi antibodies in children surveyed between 1994 and 1995 and between 1995 and 1999. RESULTS In the first period, 5,948 children were surveyed and in the second, 5,069 children were studied. Twenty children (0.4%) were positive for Trypanosoma cruzi antibodies in the second survey. These figures were significantly lower than the 1.1% prevalence detected between 1994 and 1995. In only three of the 20 cases, the transmission through vectors was confirmed, which represents a 99.4% reduction of this way of transmission. CONCLUSIONS Based on these findings, the Commission certified that Chile is the second country in Latin America to interrupt the vector transmission of Chagas disease. The successful public health program for Chagas disease will have a positive impact improving the quality of life of rural populations, that are most exposed to the disease.
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Affiliation(s)
- M Lorca
- Programa de Parasitología, ICBM, Facultad de Medicina, Universidad de Chile.
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Valverde MA, Rojas P, Amigo J, Cosmelli D, Orio P, Bahamonde MI, Mann GE, Vergara C, Latorre R. Acute activation of Maxi-K channels (hSlo) by estradiol binding to the beta subunit. Science 1999; 285:1929-31. [PMID: 10489376 DOI: 10.1126/science.285.5435.1929] [Citation(s) in RCA: 401] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Maxi-K channels consist of a pore-forming alpha subunit and a regulatory beta subunit, which confers the channel with a higher Ca(2+) sensitivity. Estradiol bound to the beta subunit and activated the Maxi-K channel (hSlo) only when both alpha and beta subunits were present. This activation was independent of the generation of intracellular signals and could be triggered by estradiol conjugated to a membrane-impenetrable carrier protein. This study documents the direct interaction of a hormone with a voltage-gated channel subunit and provides the molecular mechanism for the modulation of vascular smooth muscle Maxi-K channels by estrogens.
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Affiliation(s)
- M A Valverde
- Departament de Ciències Experimentals i de la Salut, Universidad Pompeu Fabra, C/Doctor Aiguader 80, 08003 Barcelona, Spain.
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Cáceres J, Burchard L, Bahamonde MI, Contreras MC, García A, Rojas A, Schenone H, Lorca M. [Epidemiological status of Chagas disease in the endemic area from Region II of Antofagasta]. Bol Chil Parasitol 1999; 54:25-9. [PMID: 10488587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
During 1997 a seroepidemiological study on Chagas' disease was carried out in 18 localities of three provinces (Tocopilla, El Loa and Antofagasta) of Region II (20 degrees 56'-26 degrees South Lat.; 70 degrees 38'-67 degrees West Long.), in order to assess the impact of the control program against Triatoma infestans launched in 1988, based on insecticide spraying of dwellings. By means of ELISA and an indirect hemagglutination test for Chagas' disease blood samples from 1,034 children under 10 years of age were examined, arising a 0.5% (3 cases) positivity. Test resulted positive in 2 (0.9%) children from the locality of San Pedro de Atacama and 1 (0.4%) from Calama city, all in the age group 6-10 year-old. However, none of their dwellings were found infested with T. infestants. These results indicate that the control program has a good possibility to prevent new human infections. It is advisable to continue the seroepidemiological and entomological vigilance and remark the necessity of increasing the effort in the study of transmission through other routes, to adopt or reinforce the pertinent preventive measures.
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Affiliation(s)
- J Cáceres
- Servicio de Salud Antofagasta, Chile
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Lorca M, Schenone H, del C Contreras M, García A, Bahamonde MI, Correa V, Valdés J, Rojas A, Jofré A. [Evaluation of a triatoma infestans eradication program in rural dwellings from the IV region, Chile, by means of serology for Chagas disease in 0-10 years old children]. Bol Chil Parasitol 1995; 50:87-91. [PMID: 8762674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The present study deals with the evaluation of the effectiveness of the measures employed in the control of Triatoma infestans, the vector of Trypanosoma cruzi infection (Chagas' disease), in the IV region of Chile through a serological follow up program. For this reason, a serological survey has been carried out in 2,783 children, from 0 to 10 years, who live in rural high endemic areas of the region. The sera were tested using an indirect hemagglutination test (IHAT) and ELISA techniques with results agreeing in 99.9% of the samples. In children with positive serology xenodiagnosis was performed and blood samples from the corresponding mothers were submitted to serology for Chagas' disease. These additional tests should allow to distinguish between congenital infection and vectorial transmission. It was observed that vectorial transmission of T. cruzi was interrupted in some localities where entomological control has been applied for 10 years, or lowered in those which have been submitted to desinsectations in the last 5 years. On the other hand, a relatively high prevalence of the infection has been detected in some localities. These results suggest an apparent increase of vectorial transmission, indicating the need of readjusting the dwellings insecticide sprayings activities to improve the measures against the vector.
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Affiliation(s)
- M Lorca
- Departamento de Parasitología, Universidad de Chile, Santiago
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Lorca M, Veloso C, Munoz P, Bahamonde MI, Garcia A. Diagnostic value of detecting specific IgA and IgM with recombinant Trypanosoma cruzi antigens in congenital Chagas' disease. Am J Trop Med Hyg 1995; 52:512-5. [PMID: 7611556 DOI: 10.4269/ajtmh.1995.52.512] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The present study compares the early diagnosis of congenital Chagas' disease with a DOT assay using recombinant antigens with immunofluorescence antibody testing (IFAT) and an enzyme-linked immunosorbent assay (ELISA). The studies were performed using cord blood and sera of 12 infected newborns (group I) and 12 uninfected ones born to Trypanosoma cruzi-infected mothers (group II). Conventional IFAT and ELISA showed positive results for IgG at high titers, in infants and mothers of both groups; IgA antibodies were detected by ELISA in four of the infected infants and IgM was detected in two of them. All sera of the uninfected infants were negative for IgA and IgM in the ELISA. Application of a DOT assay using eight recombinant T. cruzi antigens allowed detection of specific IgA in the cord blood of six of the infected cases and IgM in eight of them. Repetition of these serologic tests in samples obtained during a monthly follow-up gave positive results for IgA in two of the initially negative infants of group I and for IgM in four of them. This means that diagnosis of congenital T. cruzi infection was confirmed, through demonstration of specific IgM, in all infected infants, and of IgA in eight of them. The importance of late detection of IgM in siblings born of infected mothers is discussed. The detection of IgM and IgA in sera obtained after birth is believed to be due to a congenital transmission of the parasite that occurred late in pregnancy. No IgA or IgM antibodies could be detected by the DOT assay in the sera of the negative controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Lorca
- Departamento de Parasitologia, Facultad de Medicina, Universidad de Chile, Santiago
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Millán T, Yévenez R, Gálvez M, Bahamonde MI. [A survey of the depressive symptoms in pregnant women at an urban primary care consultation office]. Rev Med Chil 1990; 118:1230-4. [PMID: 2152648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We studied the frequency of depression as well as biomedical and social features of 179 pregnant women under control at an urban clinic in metropolitan Santiago. The random sample comprised 38% of all controlled pregnancies. A questionnaire adapted and validated by Florenzano et al was used to appraise depression. The Graffar methodology was used to measure socioeconomic level. Frequency of depressive symptoms was 30% and mean age of depressed women was 27.3 years, similar to non depressed ones (26.1%). A significantly higher proportion of depression was found in single women and those having a dystocic last delivery. The high frequency of depression in this vulnerable group suggests the need for integrated obstetric-psychiatric units to provide a more comprehensive medical care to theses patients.
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Affiliation(s)
- T Millán
- Departamento de Salud Pública, Facultad de Medicina Universidad de Chile (División Occidente), Santiago
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