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Thomas J. Jentsch - One of the best experts on this subject based on the ideXlab platform.

  • discovery of CLC transport proteins cloning structure function and pathophysiology
    The Journal of Physiology, 2015
    Co-Authors: Thomas J. Jentsch
    Abstract:

    After providing a personal description of the convoluted path leading 25 years ago to the molecular identification of the Torpedo Cl(-) channel CLC-0 and the discovery of the CLC Gene family, I succinctly describe the General structural and functional features of these ion transporters before giving a short overview of mammalian CLCs. These can be categorized into plasma membrane Cl(-) channels and vesicular Cl(-) /H(+) -exchangers. They are involved in the regulation of membrane excitability, transepithelial transport, extracellular ion homeostasis, endocytosis and lysosomal function. Diseases caused by CLC dysfunction include myotonia, neurodeGeneration, deafness, blindness, leukodystrophy, male infertility, renal salt loss, kidney stones and osteopetrosis, revealing a surprisingly broad spectrum of biological roles for chloride transport that was unsuspected when I set out to clone the first voltage-gated chloride channel.

  • cell biology and physiology of CLC chloride channels and transporters
    Comprehensive Physiology, 2012
    Co-Authors: Tobias Stauber, Stefanie Weinert, Thomas J. Jentsch
    Abstract:

    Proteins of the CLC Gene family assemble to homo- or sometimes heterodimers and either function as Cl(-) channels or as Cl(-)/H(+)-exchangers. CLC proteins are present in all phyla. Detailed structural information is available from crystal structures of bacterial and algal CLCs. Mammals express nine CLC Genes, four of which encode Cl(-) channels and five 2Cl(-)/H(+)-exchangers. Two accessory β-subunits are known: (1) barttin and (2) Ostm1. CLC-Ka and CLC-Kb Cl(-) channels need barttin, whereas Ostm1 is required for the function of the lysosomal CLC-7 2Cl(-)/H(+)-exchanger. CLC-1, -2, -Ka and -Kb Cl(-) channels reside in the plasma membrane and function in the control of electrical excitability of muscles or neurons, in extra- and intracellular ion homeostasis, and in transepithelial transport. The mainly endosomal/lysosomal Cl(-)/H(+)-exchangers CLC-3 to CLC-7 may facilitate vesicular acidification by shunting currents of proton pumps and increase vesicular Cl(-) concentration. CLC-3 is also present on synaptic vesicles, whereas CLC-4 and -5 can reach the plasma membrane to some extent. CLC-7/Ostm1 is coinserted with the vesicular H(+)-ATPase into the acid-secreting ruffled border membrane of osteoclasts. Mice or humans lacking CLC-7 or Ostm1 display osteopetrosis and lysosomal storage disease. Disruption of the endosomal CLC-5 Cl(-)/H(+)-exchanger leads to proteinuria and Dent's disease. Mouse models in which CLC-5 or CLC-7 is converted to uncoupled Cl(-) conductors suggest an important role of vesicular Cl(-) accumulation in these pathologies. The important functions of CLC Cl(-) channels were also revealed by human diseases and mouse models, with phenotypes including myotonia, renal loss of salt and water, deafness, blindness, leukodystrophy, and male infertility.

  • residues important for nitrate proton coupling in plant and mammalian CLC transporters
    Journal of Biological Chemistry, 2009
    Co-Authors: Eunyeong Bergsdorf, Anselm A Zdebik, Thomas J. Jentsch
    Abstract:

    Members of the CLC Gene family either function as chloride channels or as anion/proton exchangers. The plant AtCLC-a uses the pH gradient across the vacuolar membrane to accumulate the nutrient NO(3)(-) in this organelle. When AtCLC-a was expressed in Xenopus oocytes, it mediated NO(3)(-)/H(+) exchange and less efficiently mediated Cl(-)/H(+) exchange. Mutating the "gating glutamate" Glu-203 to alanine resulted in an uncoupled anion conductance that was larger for Cl(-) than NO(3)(-). Replacing the "proton glutamate" Glu-270 by alanine abolished currents. These could be restored by the uncoupling E203A mutation. Whereas mammalian endosomal CLC-4 and CLC-5 mediate stoichiometrically coupled 2Cl(-)/H(+) exchange, their NO(3)(-) transport is largely uncoupled from protons. By contrast, the AtCLC-a-mediated NO(3)(-) accumulation in plant vacuoles requires tight NO(3)(-)/H(+) coupling. Comparison of AtCLC-a and CLC-5 sequences identified a proline in AtCLC-a that is replaced by serine in all mammalian CLC isoforms. When this proline was mutated to serine (P160S), Cl(-)/H(+) exchange of AtCLC-a proceeded as efficiently as NO(3)(-)/H(+) exchange, suggesting a role of this residue in NO(3)(-)/H(+) exchange. Indeed, when the corresponding serine of CLC-5 was replaced by proline, this Cl(-)/H(+) exchanger gained efficient NO(3)(-)/H(+) coupling. When inserted into the model Torpedo chloride channel CLC-0, the equivalent mutation increased nitrate relative to chloride conductance. Hence, proline in the CLC pore signature sequence is important for NO(3)(-)/H(+) exchange and NO(3)(-) conductance both in plants and mammals. Gating and proton glutamates play similar roles in bacterial, plant, and mammalian CLC anion/proton exchangers.

  • a family of putative chloride channels from arabidopsis and functional complementation of a yeast strain with a CLC Gene disruption
    Journal of Biological Chemistry, 1996
    Co-Authors: Mirko Hechenberger, Thomas J. Jentsch, Blanche Schwappach, Wolf N Fischer, Wolf B Frommer, Klaus Steinmeyer
    Abstract:

    Abstract We have cloned four novel members of the CLC family of chloride channels from Arabidopsis thaliana. The four plant Genes are homologous to a recently isolated chloride channel Gene from tobacco (CLC-Nt1; Lurin, C., Geelen, D., Barbier-Brygoo, H., Guern, J., and Maurel, C. (1996) Plant Cell 8, 701-711) and are about 30% identical in sequence to the most closely related CLC-6 and CLC-7 putative chloride channels from mammalia. AtCLC transcripts are broadly expressed in the plant. Similarly, antibodies against the AtCLC-d protein detected the protein in all tissues, but predominantly in the silique. AtCLC-a and AtCLC-b are highly homologous to each other (≈87% identity), while being ≈50% identical to either AtCLC-c or AtCLC-d. None of the four cDNAs elicited chloride currents when expressed in Xenopus oocytes, either singly or in combination. Among these Genes, only AtCLC-d could functionally substitute for the single yeast CLC protein, restoring iron-limited growth of a strain disrupted for this Gene. Introduction of disease causing mutations, identified in human CLC Genes, abolished this capacity. Consistent with a similar function of both proteins, the green fluorescent protein-tagged AtCLC-d protein showed the identical localization pattern as the yeast ScCLC protein. This suggests that in Arabidopsis AtCLC-d functions as an intracellular chloride channel.

  • Properties of voltage-gated chloride channels of the CLC Gene family.
    The Journal of Physiology, 1995
    Co-Authors: Thomas J. Jentsch, Willy Günther, Michael Pusch, Blanche Schwappach
    Abstract:

    We review the properties of CLC chloride channels, members of an expanding Gene family originally discovered by the cloning of the CLC-0 chloride channel from Torpedo electric organ. There are at least nine different CLC Genes in mammals, several of which seem to be expressed ubiquitously, while others are expressed in a highly specific manner (e.g. the muscle-specific CLC-1 channel and the kidney-specific CLC-K channels). The newly cloned rat CLC-4 is strongly expressed in liver and brain, but also in heart, muscle, kidney and spleen. CLC chloride channels are structurally unrelated to other channel proteins and have twelve putative transmembrane domains. They function as multimers with probably four subunits. Functional characterization is most advanced with CLC-0, CLC-1 (mutations which cause myotonia) and CLC-2, a swelling-activated chloride channel. Many of the new CLC family members cannot yet be expressed functionally.

Yuliya S Nikolova - One of the best experts on this subject based on the ideXlab platform.

  • correction novel polygenic risk score as a translational tool linking depression related changes in the corticolimbic transcriptome with neural face processing and anhedonic symptoms
    Translational Psychiatry, 2020
    Co-Authors: Klara Mareckova, Colin Hawco, Fernanda Dos C Santos, Arin Bakht, Navona Calarco, Amy Miles, Aristotle N Voineskos, Etienne Sibille, Ahmad R Hariri, Yuliya S Nikolova
    Abstract:

    Convergent data from imaging and postmortem brain transcriptome studies implicate corticolimbic circuit (CLC) dysregulation in the pathophysiology of depression. To more directly bridge these lines of work, we Generated a novel transcriptome-based polygenic risk score (T-PRS), capturing subtle shifts toward depression-like Gene expression patterns in key CLC regions, and mapped this T-PRS onto brain function and related depressive symptoms in a nonclinical sample of 478 young adults (225 men; age 19.79 +/- 1.24) from the Duke NeuroGenetics Study. First, T-PRS was Generated based on common functional SNPs shifting CLC Gene expression toward a depression-like state. Next, we used multivariate partial least squares regression to map T-PRS onto whole-brain activity patterns during perceptual processing of social stimuli (i.e., human faces). For validation, we conducted a comparative analysis with a PRS summarizing depression risk variants identified by the Psychiatric Genomics Consortium (PGC-PRS). Sex was modeled as moderating factor. We showed that T-PRS was associated with widespread reductions in neural response to neutral faces in women and to emotional faces and shapes in men (multivariate p < 0.01). This female-specific reductions in neural response to neutral faces was also associated with PGC-PRS (multivariate p < 0.03). Reduced reactivity to neutral faces was further associated with increased self-reported anhedonia. We conclude that women with functional alleles mimicking the postmortem transcriptomic CLC signature of depression have blunted neural activity to social stimuli, which may be expressed as higher anhedonia.

  • novel polygenic risk score as a translational tool linking depression related changes in the corticolimbic transcriptome with neural face processing and anhedonic symptoms
    bioRxiv, 2020
    Co-Authors: Klara Mareckova, Colin Hawco, Fernanda Dos C Santos, Arin Bakht, Navona Calarco, Amy Miles, Aristotle N Voineskos, Etienne Sibille, Ahmad R Hariri, Yuliya S Nikolova
    Abstract:

    Convergent data from imaging and postmortem brain transcriptome studies implicate corticolimbic circuit (CLC) dysregulation in the pathophysiology of depression. To more directly bridge these lines of work, we Generated a novel transcriptome-based polygenic risk score (T-PRS), capturing subtle shifts towards depression-like Gene expression patterns in key CLC regions, and mapped this T-PRS onto brain function and related depressive symptoms in a non-clinical sample of 478 young adults (225 men; age 19.79+/-1.24) from the Duke NeuroGenetics Study. First, T-PRS was Generated based on common functional SNPs shifting CLC Gene expression towards a depression-like state. Next, we used multivariate partial least squares regression to map T-PRS onto whole-brain activity patterns during perceptual processing of social stimuli (i.e., human faces). For validation, we conducted a comparative analysis with a PRS summarizing depression risk variants identified by the Psychiatric Genomics Consortium (PGC-PRS). Sex was modeled as moderating factor. We showed that T-PRS was associated with widespread reductions in neural response to neutral faces in women and to emotional faces and shapes in men (multivariate p

Steven J. Ackerman - One of the best experts on this subject based on the ideXlab platform.

  • human eosinophil charcot leyden crystal protein cloning and characterization of a lysophospholipase Gene promoter
    Blood, 1993
    Co-Authors: Hilary I Gomolin, Steven J. Ackerman, Yuji Yamaguchi, Angela V Paulpillai, Laura A Dvorak, Daniel G Tenen
    Abstract:

    The Charcot-Leyden crystal (CLC) protein is a lysophospholipase expressed exclusively by eosinophils and basophils. During eosinophilic differentiation of eosinophil-committed cell lines, CLC steady state mRNA levels increase significantly. This increased expression is transcriptionally regulated during butyrate induction of an eosinophilic subline (C15) of the promyelocytic leukemia cell line HL- 60, as shown by nuclear run-on assays. The transcriptional start site of the CLC Gene was identified 43 bp upstream of the 5′ end of the longest available cDNA sequence. The Gene encoding CLC protein was cloned from a chromosome 19-specific library and a fragment overlapping the transcriptional start site was isolated and sequenced. Plasmid constructs (in the pXP2 luciferase expression vector) containing 411 and 292 bp of genomic sequence upstream of the CLC transcriptional start site directed reporter Gene expression in transient transfections of HL-60-C15 cells, as well as other myeloid (U937) and nonmyeloid (HeLa and RPMI 8402) cell lines. However, the differential expression of the two CLC promoter constructs in these cell lines suggests that the -292 to -411 bp region of the promoter may confer some specificity for expression in the eosinophil lineage. The CLC promoter sequence contains two consensus GATA binding sites, a purine-rich sequence that presents potential binding sites for PU.1, a member of the ets family of Genes, as well as sequences described in other myeloid-specific promoters. This is the first demonstration of a functional eosinophil promoter that could serve as a model for identifying DNA elements and trans-activating factors that regulate Gene expression during the commitment and differentiation of the eosinophil lineage.

  • the Gene for human eosinophil charcot leyden crystal protein directs expression of lysophospholipase activity and spontaneous crystallization in transiently transfected cos cells
    Journal of Leukocyte Biology, 1992
    Co-Authors: Zeqi Zhou, Daniel G Tenen, Ann M Dvorak, Steven J. Ackerman
    Abstract:

    Expression of the Gene encoding human eosinophil lysophospholipase, the Charcot-Leyden crystal (CLC) protein, was studied in transiently transfected COS cells. Recombinant CLC (rCLC) protein expression was demonstrated both by Western blot and radioimmunoassay inhibition analyses of transfected COS cell extracts and by immunofluorescent staining and ultrastructural immunogold analyses of intact cells. The rCLC protein was immunochemically indistinguishable from native eosinophil-derived CLC protein, and each transfected COS cell expressed approximately 11 pg of rCLC protein as determined by radioimmunoassay and assessment of transfection efficiency. Immunofluorescent microscopy and ultrastructural immunogold analyses localized rCLC protein to the nucleus, cytoplasm, and plasma membrane of COS cells. Lysates from transfected COS cells producing CLC protein expressed significant lysophospholipase activity. Furthermore, rCLC protein expressed in COS cells spontaneously formed the distinctive intracytoplasmic and intranuclear hexagonal bipyramidal crystals characteristic of the native eosinophil and basophil-derived protein. Expression of the CLC Gene confirms the authenticity of the CLC cDNA, the expression of lysophospholipase activity by this unique eosinophil and basophil constituent, and will facilitate the routine purification of the active enzyme for in vitro and animal model studies of its role (or roles) in eosinophil and basophil associated allergic inflammation and eosinophil-parasite interactions.

Hiroaki Miyazaki - One of the best experts on this subject based on the ideXlab platform.

  • localization of mouse CLC 6 and CLC 7 mrna and their functional complementation of yeast CLC Gene mutant
    Histochemistry and Cell Biology, 2001
    Co-Authors: Yujiro Kida, Shinichi Uchida, Hiroaki Miyazaki, Sei Sasaki, Fumiaki Marumo
    Abstract:

    CLC-6 and CLC-7 belong to the family of voltage-dependent chloride channels. To learn more about the in vivo roles of CLC-6 and CLC-7, we performed in situ hybridization of these CLC channels in various mouse organs. Mouse CLC-6 (mCLC-6) was expressed in the peripheral region of seminiferous tubules in the testis, tracheal epithelium, epithelium of bronchioles, alveolar cells in the lung, acinar cells in the pancreas, and intestinal epithelium, but we could not detect signals from pancreatic islets. Mouse CLC-7 (mCLC-7) was expressed in neurons in the medulla oblongata, Purkinje cells in the cerebellum, proximal tubules in the kidney, and hepatocytes in the liver. The distribution of mCLC-6 and mCLC-7 were similar in the lung, pancreas, and testis. mCLC-6 functionally complemented the gef1 phenotype of a yeast strain in which a single CLC channel (GEF1) had been disrupted by homologous recombination. In contrast, mCLC-7 did not complement this gef1 phenotype. This study identified the cell types that express mCLC-6 and mCLC-7 in the mouse tissues, and the complementation assay suggested that mCLC-6 functions as an intracellular chloride channel.

  • molecular cloning of CLC chloride channels in oreochromis mossambicus and their functional complementation of yeast CLC Gene mutant
    Biochemical and Biophysical Research Communications, 1999
    Co-Authors: Shinichi Uchida, Hiroaki Miyazaki, Fumiaki Marumo, Yoshio Takei, Tetsuya Hirano, Sei Sasaki
    Abstract:

    Abstract We have cloned two members of the CLC chloride channel family (OmCLC-3 and OmCLC-5) from gill cDNA libraries of the euryhaline tilapiaOreochromis mosammbicus.At the amino acid level, OmCLC-3 is 90.5% identical to rat CLC-3 and OmCLC-5 is 79.2% identical to rat CLC-5. Ribonuclease protection assay revealed that OmCLC-5 was mainly expressed in the gill, kidney, and intestine in both freshwater- (FW) and seawater- (SW) adapted tilapia. Although the mRNA of OmCLC-3 was broadly expressed in tissues of FW- and SW-adapted tilapia, the most intense signals were observed in the gill, kidney, intestine, and brain. Injection of OmCLC-3 and OmCLC-5 cRNAs intoXenopusoocytes did not elicit chloride currents, but these clones did functionally complement thegef1phenotype of YPH250(gef), a yeast strain in which a single CLC channel (GEF1) has been disrupted by homologous recombination. These results clearly indicated that CLC channels closely related to the mammalian CLC-3, -4, and -5 subfamily exist also in tilapia and that OmCLC-3 and OmCLC-5 function as intracellular chloride channels.

Sei Sasaki - One of the best experts on this subject based on the ideXlab platform.

  • localization of mouse CLC 6 and CLC 7 mrna and their functional complementation of yeast CLC Gene mutant
    Histochemistry and Cell Biology, 2001
    Co-Authors: Yujiro Kida, Shinichi Uchida, Hiroaki Miyazaki, Sei Sasaki, Fumiaki Marumo
    Abstract:

    CLC-6 and CLC-7 belong to the family of voltage-dependent chloride channels. To learn more about the in vivo roles of CLC-6 and CLC-7, we performed in situ hybridization of these CLC channels in various mouse organs. Mouse CLC-6 (mCLC-6) was expressed in the peripheral region of seminiferous tubules in the testis, tracheal epithelium, epithelium of bronchioles, alveolar cells in the lung, acinar cells in the pancreas, and intestinal epithelium, but we could not detect signals from pancreatic islets. Mouse CLC-7 (mCLC-7) was expressed in neurons in the medulla oblongata, Purkinje cells in the cerebellum, proximal tubules in the kidney, and hepatocytes in the liver. The distribution of mCLC-6 and mCLC-7 were similar in the lung, pancreas, and testis. mCLC-6 functionally complemented the gef1 phenotype of a yeast strain in which a single CLC channel (GEF1) had been disrupted by homologous recombination. In contrast, mCLC-7 did not complement this gef1 phenotype. This study identified the cell types that express mCLC-6 and mCLC-7 in the mouse tissues, and the complementation assay suggested that mCLC-6 functions as an intracellular chloride channel.

  • molecular cloning of CLC chloride channels in oreochromis mossambicus and their functional complementation of yeast CLC Gene mutant
    Biochemical and Biophysical Research Communications, 1999
    Co-Authors: Shinichi Uchida, Hiroaki Miyazaki, Fumiaki Marumo, Yoshio Takei, Tetsuya Hirano, Sei Sasaki
    Abstract:

    Abstract We have cloned two members of the CLC chloride channel family (OmCLC-3 and OmCLC-5) from gill cDNA libraries of the euryhaline tilapiaOreochromis mosammbicus.At the amino acid level, OmCLC-3 is 90.5% identical to rat CLC-3 and OmCLC-5 is 79.2% identical to rat CLC-5. Ribonuclease protection assay revealed that OmCLC-5 was mainly expressed in the gill, kidney, and intestine in both freshwater- (FW) and seawater- (SW) adapted tilapia. Although the mRNA of OmCLC-3 was broadly expressed in tissues of FW- and SW-adapted tilapia, the most intense signals were observed in the gill, kidney, intestine, and brain. Injection of OmCLC-3 and OmCLC-5 cRNAs intoXenopusoocytes did not elicit chloride currents, but these clones did functionally complement thegef1phenotype of YPH250(gef), a yeast strain in which a single CLC channel (GEF1) has been disrupted by homologous recombination. These results clearly indicated that CLC channels closely related to the mammalian CLC-3, -4, and -5 subfamily exist also in tilapia and that OmCLC-3 and OmCLC-5 function as intracellular chloride channels.