... , Authors: Velayuthan C Padmakumar, Stuart H Yuspa. Published in: Atlas Genet Cytogenet Oncol Haematol.
AbstractBackground and Aim:Our previous proteomic research found that chloride intracellular channel 1 (CLIC1) was upregulated in hepatocellular carcinoma (HCC) tissues with portal vein tumor thrombus. The present study aimed to determine the role of CLIC1 in HCC invasion.Methods:Immunohistochemistr
Chloride channels are a superfamily of poorly understood ion channels specific for chloride. These channels may conduct many different ions, but are named for chloride because its concentration in vivo is much higher than other anions. Several families of voltage-gated channels and ligand-gated channels (e.g., the CaCC families) have been characterized in humans. Voltage-gated chloride channels display a variety of important physiological and cellular roles that include regulation of pH, volume homeostasis, organic solute transport, cell migration, cell proliferation and differentiation. Based on sequence homology the chloride channels can be subdivided into a number of groups. Voltage-gated chloride channels are important for setting cell resting membrane potential and maintaining proper cell volume. These channels conduct Cl− as well as other anions such as HCO− 3, I−, SCN−, and NO− 3. The structure of these channels are not like other known channels. The chloride channel subunits ...
0017] Also provided herein is a method of identifying an agent that is an inhibitor of a calcium-activated chloride channel comprising: (a) contacting a cell and a candidate agent in a test sample, (under conditions and for a time sufficient) to permit interaction between the candidate agent and the cell, wherein the cell comprises (i) a calcium-activated chloride channel and (ii) a cytoplasmic indicator protein that binds halide; (b) adding to the test sample (i) at least one calcium-elevating agonist and (ii) iodide, under conditions and for a time sufficient for the calcium-elevating agonist to bind to the cell (i.e., to permit binding of the calcium-elevating agonist to the cell), wherein binding of the calcium-elevating agonist to the cell increases the level of calcium ion (Ca2+) in the cell; and (c) determining the level of iodide influx in the presence of the candidate agent and comparing the level of iodide influx in the presence of the candidate agent with the level of iodide influx in ...
Two new calcium-activated chloride channel (CLCA) family members, mCLCA5 and mCLCA6, have been cloned from mouse eye and intestine, respectively. mCLCA5 is highly homologous to hCLCA2, and mCLCA6 is highly homologous to hCLCA4. mCLCA5 is widely expressed with strong expression in eye and spleen, whe …
RefSeq Summary (NM_001288): Chloride channels are a diverse group of proteins that regulate fundamental cellular processes including stabilization of cell membrane potential, transepithelial transport, maintenance of intracellular pH, and regulation of cell volume. Chloride intracellular channel 1 is a member of the p64 family; the protein localizes principally to the cell nucleus and exhibits both nuclear and plasma membrane chloride ion channel activity. [provided by RefSeq, Jul 2008 ...
Read "Permeant Anions Control Gating of Calcium-dependent Chloride Channels, The Journal of Membrane Biology" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
CLIC1 antibody, N-term (chloride intracellular channel 1) for IHC-P, WB. Anti-CLIC1 pAb (GTX48722) is tested in Human, Mouse samples. 100% Ab-Assurance.
Anoctamins and Bestrophins are two kinds of calcium-activated chloride channels. Anoctamins were shown to be Ca-activated Cl channels in 2008 and are responsible for the classical CaCCs that are widely expressed in many tissues, especially epithelia. Bestrophins are more restricted in their expression and play more specialized roles. Bestrophin-1 is expressed in the retinal pigment epithelium and certain mutations in bestrophin-1 cause degeneration of the retina and blindness. Bestrophin-2 is expressed in goblet cells in colon and may play a role in bicarbonate secretion in this tissue. We are interested in understanding how both anoctamins and bestrophins are regulated by calcium. We are identifying the calcium binding sites and the molecular links between the calcium sensor and the channel gate using a combination of both whole-cell and single channel electrophysiological mesurements and mutagenesis. We are dissecting the signaling protein network associated with these channels using ...
Plasma membrane Cl- channels perform a variety of functions, including control of excitability in neurons and muscle, cell volume regulation and transepithelial transport. Structurally, three classes of Cl- channels have been identified: ligand-gated, postsynaptic Cl- channels (e.g. GABA and glycine receptors); the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels (which belong to the traffic ATPase superfamily); and the CLC family of Cl- channels. Recent developments of note include further characterization of the expanding CLC Cl- channel family, advances in understanding the regulation of the CFTR Cl- channel and its emergent role as a regulator of other channels, clarification of issues related to swelling-activated Cl- channels, and the discovery that several co-transporter molecules are now known to induce Cl- currents in Xenopus oocytes.. ...
Proteins encoded by best1 to -3 genes are implicated as molecular correlates of calcium-activated chloride channels in epithelia. In this issue of Circulation Research, Matchkov et al present compelling evidence that best-3 expression is essential for the generation of calcium-sensitive cGMP-dependent chloride channels in rat mesenteric artery.1. Chloride channels are enigmatic beasts. Numerous phenotypes exist, as determined by their mode of activation, channel kinetics, and pore properties, but the molecular identity has only really been identified for the voltage-dependent Cl− channels (CLCs) and the cAMP-dependent, cystic fibrosis transmembrane regulator (CFTR) channels. For the other types of Cl− channels, there is far less certainty about the molecular identity. Many candidates for the swelling-activated Cl− channel have been promulgated that ultimately have been repudiated.2 Similarly, the molecular identity of the Ca2+-gated Cl− channel, common to vascular smooth muscle cells, ...
May be involved in mediating calcium-activated chloride conductance (PubMed:8537359). May play critical roles in goblet cell metaplasia, mucus hypersecretion, cystic fibrosis and AHR. May be involved in the regulation of mucus production and/or secretion by goblet cells. Involved in the regulation of tissue inflammation in the innate immune response. May play a role as a tumor suppressor. Induces MUC5AC.
High blood pressure is the leading risk factor for death worldwide. One of the hallmarks is a rise of peripheral vascular resistance, which largely depends on arteriole tone. Ca2+-activated chloride currents (CaCCs) in vascular smooth muscle cells (VSMCs) are candidates for increasing vascular contractility. We analyzed the vascular tree and identified substantial CaCCs in VSMCs of the aorta and carotid arteries. CaCCs were small or absent in VSMCs of medium-sized vessels such as mesenteric arteries and larger retinal arterioles. In small vessels of the retina, brain, and skeletal muscle, where contractile intermediate cells or pericytes gradually replace VSMCs, CaCCs were particularly large. Targeted disruption of the calcium-activated chloride channel TMEM16A, also known as ANO1, in VSMCs, intermediate cells, and pericytes eliminated CaCCs in all vessels studied. Mice lacking vascular TMEM16A had lower systemic blood pressure and a decreased hypertensive response following vasoconstrictor ...
TY - JOUR. T1 - Characterization of a native swelling-induced chloride current, ICl.swell, and its regulatory protein, pICln, in Xenopus oocytes.. AU - Ackerman, Michael John. AU - Krapivinsky, G. B.. AU - Gordon, E.. AU - Krapivinsky, L.. AU - Clapham, D. C.. PY - 1994. Y1 - 1994. N2 - The ability to precisely regulate cell volume is a fundamental property of most cells. Although the phenomenon of regulatory volume decrease (RVD), whereby a swollen cell loses salt and water to restore its original volume, has been appreciated for decades, the molecular identities of the proteins responsible for the volume control machinery and their regulation are essentially unknown. It appears that the rate-determining step in gaining volume control involves the activation of potassium and chloride conductance pathways. We have identified a native chloride current (ICl.swell) responsive to cell swelling in Xenopus oocytes [Ackerman et al. (1994) J Gen Physiol 103: 153-179]. Moreover, we have demonstrated that ...
Chloride-conducting ion channels of the ClC family are emerging as critical contributors to a host of biological processes. These polytopic membrane proteins form aqueous pathways through which anions are selectively allowed to pass down their concentration gradients. The ClCs are found in nearly all organisms, with members in every mammalian tissue, yet relatively little is known about their mechanism or regulation. It is clear, however, that they are fundamentally different in molecular construction and mechanism from the well-known potassium-, sodium-, and calcium-selective channels. The medical importance of ClC channels - four inherited diseases have been blamed on familial ClC dysfunction to date - highlights their diverse physiological functions and provides strong motivation for further study.
The CLC family of chloride channels and transporters is made up by nine members but just three of these ClC-Ka/b ClC-7 and ClC-2 have already been found up to now connected with auxiliary subunits. immunoglobulin (Ig)-like domains regulates its subcellular localization and activity in glial cells. The normal theme for these three proteins can be their requirement of an effective homeostasis since their breakdown leads to specific illnesses. We will review right here their properties and their part in regular chloride physiology as well as the pathological outcomes of their incorrect function. Intro Chloride is very important to many biological features such Apremilast as for example transepithelial fluid transportation acidification of intracellular organelles muscle tissue contraction neuronal membrane potential or cell quantity rules. Chloride flux across membranes is mediated by several classes of proteins (Duran oocytes or in transfected cells (Steinmeyer gene lead to classical Bartter ...
Miller, A. N.*, Vaisey, G.*, & Long, S. B. (2019). Molecular mechanisms of gating in the calcium-activated chloride channel bestrophin. eLife (Abstract , open state Cryo-EM map , Atomic Coordinates). *A. N. Miller and G. Vaisey are co-first authors.. Vaisey, G., & Long, S. B. (2018). An allosteric mechanism of inactivation in the calcium-dependent chloride channel BEST1. The Journal of General Physiology, jgp.201812190. (Abstract). Hou, X., Burstein, S. R., & Long, S. B. (2018). Structures reveal opening of the store-operated calcium channel Orai. eLife, 7. (Manuscript , Atomic Coordinates). Baradaran, R., Wang, C., Siliciano, A. F., & Long, S. B. (2018). Cryo-EM structures of fungal and metazoan mitochondrial calcium uniporters. Nature, 559(7715), 580-584. (Abstract , Atomic Coordinates , Cryo-EM map). Melinda Diver, Leanne Pedi, Akiko Koide, Shohei Koide, Stephen B. Long (2018). Atomic structure of the eukaryotic intramembrane RAS methyltransferase ICMT. Nature. Jan 25; 553(7689):526-529. ...
Furthermore, the inhibitor pharmacology of the VACC also confirms that they are VACCs. Conventional chloride channel blockers such as NPPB and DIDS significantly inhibited the volume-activated currents, indicating that they are chloride channels (21). In various cell types, DIDS has been shown to inhibit VACCs in voltage-dependent fashion (26, 32, 33) in addition to inhibiting calcium-activated chloride channels (1, 3), outwardly rectifying chloride channels (5), and ATP release (5) but does not inhibit CFTR (1, 10). Thus the voltage-dependent inhibition of volume-activated current by DIDS implies that chloride conductance via CFTR may not play a major role in RVD in cholangiocytes, and this conclusion is consistent with the previous finding that cAMP agonists had no significant effect on RVD in cholangiocytes (6). The VACCs are also inhibited by glybenclamide (Fig. 5C), which is a known inhibitor of CFTR, VACCs, as well as ATP-sensitive potassium channels (27). Moreover, the significant ...
Superfusion of BC3H1 cells with the normal hyposmotic solution caused cell swelling accompanied by a large increase in membrane currents in all the tested cells (Fig. 1 A). Membrane currents returned to basal level after switching back to isosmotic solution (Voets et al., 1997). Current-voltage relations reconstructed from voltage ramps applied during the hyposmotic challenge (Fig. 1 B) show that the swelling-activated current reverses close to ECl (−20 mV). We have previously shown that this current is a Cl− current, ICl,swell, with an I− , Br− , Cl− ,, gluconate anion permeability sequence and that it is efficiently blocked by niflumic acid, flufenamic acid, and NPPB (Voets et al., 1997). This current inactivates during voltage steps to positive potentials ,+40 mV (Fig. 1 C). The negative slope of the current-voltage relation seen at very positive potentials (Fig. 1 B) is due to inactivation of the current during the slow voltage ramp.. We observed single-channel Cl− currents in ...
Ion channels catalyze the transportation of small ions across the cell membrane and, in doing so, maintain normal cellular functions. To achieve functional flexibility, these membrane proteins are regulated by a variety of factors, such as transmembrane voltages, mechanical stretches, extracellular or intracellular ligands, and sometimes the small ions in the aqueous solution (Hille 1992). In vertebrate skeletal muscles, for instance, external Cl− and H+ significantly influence the resting membrane conductance and, thus, control the firing pattern of action potentials (Hodgkin and Horowicz 1959, Hodgkin and Horowicz 1960). Electrophysiological recordings and flux assays have shown that the muscle membrane is more permeable to Cl− than to K+ (Hodgkin and Horowicz 1959; Hutter and Padsha 1959; Hutter and Noble 1960), and if the Cl− conductance is removed, the membrane current shows little change when the pH is altered (Hutter and Warner 1967, Hutter and Warner 1972). These early studies ...
Oxyntic cells that retain distinct morphological polarity between apical and basolateral membranes were isolated from the gastric mucosa of the amphibian Necturus. Patch-clamp techniques were applied to these cells to identify apical membrane ion channels associated with hydrochloric acid secretion. A single class of voltage-dependent, inwardly rectifying chloride channels was observed in the apical membranes of both resting and stimulated (acid-secreting) oxyntic cells. Stimulation of the cells with dibutyryladenosine 3,5-monophosphate and isobutylmethylxanthine increased channel open probability and simultaneously increased apical membrane surface area. This chloride channel is probably responsible for electrogenic chloride secretion by the gastric mucosa and may also participate in the fluid- and enzyme-secretory functions of the oxyntic cell, analogous to the chloride channels found in the apical membranes of other exocrine cells. ...
In mature mammalian muscle, the chloride conductance of the membrane is an important factor in the regulation of excitability. Up to now, no ligand was available for the biochemical characterization of muscle chloride channels. In order to localize and characterize these channels, we have used indanyloxyacetic acid (IAA)-94, a ligand previously used for epithelial Cl- channels (Landry, D. W., Reitman, M., Cragoe, E. J., Jr., and Al-Awqati, Q. (1987) J. Gen. Physiol. 90, 779-798; Landry, D. W., Akabas, M. H., Redhead, C., Edelman, A., Cragoe, E. J., Jr., and Al-Awqati, Q. (1989) Science 244, 1469-1472). IAA induced myotonic responses when microinjected into mature mouse muscle fibers, indicating a blockade of Cl- channels from the cytoplasmic side. Membrane vesicles were prepared from rabbit skeletal muscle and separated by sucrose gradient centrifugation. Fractions obtained (in the order of increasing density) were sarcolemma (SL), T-tubules (TT), sarcoplasmatic reticulum (SR), and triads and ...
Shikonin is a major component of a Chinese herbal medicine named zicao. Shikonin is a potent TMEM16A chloride channel inhibitor with an IC50 of 6.5 μM. Shikonin is a specific pyruvate kinase M2 (PKM2) inhibitor and can also inhibit TNF-α and NF-κB pathway. - Mechanism of Action & Protocol.
Calcium-activated chloride channel (CaCC) which plays an important role in transepithelial anion transport and smooth muscle contraction. Required for the normal functioning of the interstitial cells of Cajal (ICCs) which generate electrical pacemaker activity in gastrointestinal smooth muscles. Acts as a major contributor to basal and stimulated chloride conductance in airway epithelial cells and plays an important role in tracheal cartilage development.
Dr. Lily Jan defines the physiological role of ion channels, like potassium channels and Calcium-Activated Chloride Channels, in the regulation of excitability in neurons.
Fusion protein amino acids 568-746 (C-terminus) of rat Clcn5 (also known as H(+)/Cl(-) exchange transporter 5, Chloride channel protein 5, Chloride transporter ClC-5, Clc5 and CLCK2, accession number P51796)Mouse: 99% identity (178/179 amino acids identical)Human: 98% identity (177/179 amino acids identical)70% identit
Catalysis of facilitated diffusion of a chloride (by an energy-independent process) involving passage through a transmembrane aqueous pore or channel without evidence for a carrier-mediated mechanism.
Myotonia is a state of hyperexcitability of skeletal-muscle fibres. Mutations in the ClC-1 Cl− channel cause recessive and dominant forms of this disease. Mutations have been described throughout the protein-coding region, including three sequence variations (A885P, R894X and P932L) in a distal C-terminal stretch of residues [CTD (C-terminal domain) region] that are not conserved between CLC proteins. We show that surface expression of these mutants is reduced in Xenopus oocytes compared with wild-type ClC-1. Functional, biochemical and NMR spectroscopy studies revealed that the CTD region encompasses a segment conserved in most voltage-dependent CLC channels that folds with a secondary structure containing a short type II poly-proline helix. We found that the myotonia-causing mutation A885P disturbs this structure by extending the poly-proline helix. We hypothesize that this structural modification results in the observed alteration of the common gate that acts on both pores of the channel. ...
Cystic fibrosis occurs due to mutation of the chromosome 7 which lead to defect in the chloride ion channel membrane ( CFTR). The common form of mutation is the ΔF508. The defect in the chloride ion channel membrane may lead to the defect in the trans
Although these experiments use cells that heterologously express CaV1.3 and hBest1, it is very likely that our results are physiologically relevant to RPE cell function. Human RPE cells and the RPE cell line ARPE-19 express CaV α1.3 and β2 subunits (Wimmers et al., 2008). Furthermore, it has been shown recently that hBest1 coimmunoprecipitates with CaVβ subunits from freshly isolated human RPE cells (Strauss et al., 2008). These results suggest that it is likely that the interaction between hBest1 and CaV subunits has an important physiological function and may help resolve the present controversy of whether Best1 is a Cl− channel (Hartzell et al., 2008).. As reviewed in the Introduction, there is strong evidence that bestrophins are Cl− channels (Hartzell et al., 2008), but this idea has been questioned (Marmorstein et al., 2004a,b, 2006; Rosenthal et al., 2005; Marmorstein and Kinnick, 2007). These authors have proposed that hBest1 is not a Cl− channel but rather is a regulator of ...
TY - JOUR. T1 - Phylogenetic shadowing of a histamine-gated chloride channel involved in insect vision. AU - Iovchev, M. AU - Boutanaev, A. AU - Ivanov, I. AU - Wolstenholme, A. AU - Nurminsky, D. AU - Semenov, E. N1 - ID number: ISI:000234767300002. PY - 2006. Y1 - 2006. N2 - A recently identified gene, hlcA (synonym: ort), codes for an ionotrophic histamine receptor Subunit in Drosophila melanogaster, and known hclA mutations lead to defects in the Visual system, neurologic disorders and changed responsiveness to neurotoxins. To investigate whether this novel class of receptors is common across the Insecta, we analysed the genomes of 15 other insect species (Diptera, Hymenoptera, Coleoptera, Lepidoptera) and revealed orthologs of hclA in all of them. The predicted receptor domain of HCLA is extensively conserved (86-100% of identity) among the 16 proteins. Minor changes in the amino acid sequence that includes the putative transmembrane domains (TMs) 1-3 were found in non-drosophilid species ...
Compare chloride channel 6 ELISA Kits from leading suppliers on Biocompare. View specifications, prices, citations, reviews, and more.
Compare chloride channel 6 ELISA Kits from leading suppliers on Biocompare. View specifications, prices, citations, reviews, and more.
A - Tilt: 12° - Segments: 1(36-65), 2(79-100), 3(126-141), 4(148-159), 5(179-190), 6(193-204), 7(215-232), 8(252-280), 9(288-307), 10(333-350), 11(357-372), 12(386-402), 13(405-416), 14(422-438 ...
One intriguing finding from theoretical calculations was the electrostatic contribution of K131 in stabilizing the Cl− binding to all three binding sites in ClC-ec1 (Faraldo-Gomez and Roux, 2004) despite the fact that the side chain of K131 does not directly line the ion transport pathway. Faraldo-Gomez and Rouxs calculations pointed out that the single most important favorable ion-side chain electrostatic interaction in ClC-ec1 originates not from the ion-contacting residues such as S107 or Y445 but from K131 (Faraldo-Gomez and Roux, 2004). A lysine residue at this position is conserved from the bacterial to the mammalian ClC proteins. To examine the functional role of the corresponding lysine residue (K149) in ClC-0, we constructed several K149 mutants, including K149E, K149D, K149A, K149L, and K149R. We have so far been unable to functionally express K149E in Xenopus oocytes. Two runs of expression of K149E and K149D mutants in HEK293 cells did not result in functional current within 5 d ...
Since anoctamin 1 ANO1 (TMEM16A) was found to be a molecular component of Ca(2+) -activated Cl(-) channels, its role in tumorigenesis has gained attention at a fast pace. ANO1 overexpression frequently occurs in the cancer tissues along with 11q13 chromosome amplification. Poor prognosis of many types of cancers has been closely correlated with ANO1 gene amplification and protein overexpression. ANO1 is now considered an excellent biomarker for certain cancers. Recent research suggests that it is the channel function of ANO1 that is involved in the tumorigenesis. However, how the overexpression of the functional ANO1 causes malignant transformation of tissues via signaling pathways, for example, MAPK remains to be investigated. Clarification of the reasons in future will avail to make ANO1 as a target for cancer treatment ...
View mouse Clcnka Chr4:141384610-141398724 with: phenotypes, sequences, polymorphisms, proteins, references, function, expression
We are delighted to share with you the latest episode of our Behind the Scenes series. Within this series, we explore the inner workings of the Consortium with a camera in hand, dedicating to showing you what takes place within the laboratory setting and outside of it.. For our second feature, we present the following video feature of Emad Tajkhorshid, an active participant in the Consortiums Computational Modeling Core and the Structural Dynamics of ABC Transporter and Conformational Dynamics in the CLC Channel/Transporter Family projects. We sat down with Emad and asked him about his work with computational modeling, how his laboratory collaborates with other entities within the Consortium, and how he views the role of the Consortium within the broader scientific community. Let us know what you think in the comments!. ...
Complete information for ANO4 gene (Protein Coding), Anoctamin 4, including: function, proteins, disorders, pathways, orthologs, and expression. GeneCards - The Human Gene Compendium
Complete information for ANO1 gene (Protein Coding), Anoctamin 1, including: function, proteins, disorders, pathways, orthologs, and expression. GeneCards - The Human Gene Compendium
韩国CLC女团,2015年3月出道,备受期待。CLC成员共5人,分别是吴承姬、崔有真、张丞延、Sorn、张睿恩。CLC是CrystaLClear的缩写,寓意成员们能像水晶一样永远保持在洁净、闪耀的模样。CLC组合早在出道前就经常在街头演出,积累经验。CLC组合中文网将会汇集CLC的新闻,以最快的速度报道CLC最全面的信息。
TMEM204兔多克隆抗体(ab113102)可与小鼠, 大鼠, 人样本反应并经WB, IHC, ICC, ICC/IF实验严格验证。所有产品均提供质保服务,中国75%以上现货。
Tmem18兔多克隆抗体(ab106597)可与小鼠, 大鼠, 人样本反应并经WB, IHC, ICC/IF实验严格验证。所有产品均提供质保服务,中国75%以上现货。
BACKGROUND: Dents disease, an X-linked renal tubular disorder, is characterized by low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and progressive renal failure. Dents disease results from mutations of the voltage-gated chloride channel CLC-5. METHODS: We studied the effect of zero and high citrate diet on renal function of ClC-5 knockout mice and wild-type mice. The mice were placed in metabolic cages from which the urine was collected. Mice were sacrificed to obtain serum and tissues for analysis. RESULTS: ClC-5 knockout mice fed zero or high citrate diet had significantly increased urinary calcium excretion compared with wild-type mice fed the same diets. Nine-month-old ClC-5 knockout mice on a zero citrate diet had significantly decreased glomerular filtration rate (GFR), whereas 9-month-old ClC-5 knockout mice on a high citrate diet had normal renal function. ClC-5 knockout mice fed a zero citrate diet had significantly increased tubular atrophy, ...
TY - JOUR. T1 - Role of calcium in volume-activated chloride currents in a mouse cholangiocyte cell line. AU - Chen, Biyi. AU - Nicol, Grant. AU - Cho, Won Kyoo. PY - 2007/1/1. Y1 - 2007/1/1. N2 - Volume-activated Cl- channels (VACCs) play vital roles in many cells including cholangiocytes. Previously, we characterized the VACCs in mouse cholangiocytes. Since calcium plays an important role in VACC regulation in many cells, we have studied the effect of calcium modulation on the regulatory volume decrease (RVD) and VACC currents in mouse bile duct cells (MBDCs). Cell volume measurements were assessed by a Coulter counter with cell sizer, and conventional whole-cell patch-clamp techniques were used to study the role of calcium on RVD and VACC currents. Cell volume study indicated that MBDCs exhibited RVD, which was inhibited by 5-nitro-2′-(3-phenylpropylamino)- benzoate (NPPB), 4,4′-diisothiocyanostilbene-2,2′-disulfonate (DIDS) and 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic ...
Abstract: : Purpose: In corneal endothelial cells, apical HCO3- permeability can be enhanced by increasing [Ca2+]i via either activation of purinergic receptor or inhibition of the sarcoendoplasmic reticulum calcium-ATPase ( SERCA ). Our goal is to identify the molecular candidate of the calcium-activated anion channel. Methods: Fresh and cultured bovine corneal endothelial cells ( FBCEC, CBCEC) were used in the study. A probe containing the first 457bp of the bCLCA1 open reading frame was used for in situ hybridization analysis. A 15 aa polypeptide (417-431) conjugate was used to generate polyclonal antibodies in rabbit. The immunoblot and immunofluoresence assay were performed to detect the protein expression of bCLCA1. Results: In situ hybridization with the bCLCA1-specific probe confirmed prominent mRNA expression in CBCEC. In immunoblot assay, the antiserum detects the heterologously expressed bCLCA1in HEK293 cell line, which was transfected with pcDNA3.1-bCLCA1 (a gift from Dr. Fuller in ...
Apical membrane chloride channels control chloride secretion by airway epithelial cells. Defective regulation of these channels is a prominent characteristic of cystic fibrosis. In normal intact cells, activation of protein kinase C (PKC) by phorbol ester either stimulated or inhibited chloride secretion, depending on the physiological status of the cell. In cell-free membrane patches, PKC also had a dual effect: at a high calcium concentration, PKC inactivated chloride channels; at a low calcium concentration, PKC activated chloride channels. In cystic fibrosis cells, PKC-dependent channel inactivation was normal, but activation was defective. Thus it appears that PKC phosphorylates and regulates two different sites on the channel or on an associated membrane protein, one of which is defective in cystic fibrosis. ...
TY - JOUR. T1 - Chloride equilibrium potential in salamander cones. AU - Thoreson, Wallace B. AU - Bryson, Eric J.. PY - 2004/12/5. Y1 - 2004/12/5. N2 - Background: GABAergic inhibition and effects of intracellular chloride ions on calcium channel activity have been proposed to regulate neurotransmission from photoreceptors. To assess the impact of these and other chloride-dependent mechanisms on release from cones, the chloride equilibrium potential (ECl) was determined in red-sensitive, large single cones from the tiger salamander retinal slice. Results: Whole cell recordings were done using gramicidin perforated patch techniques to maintain endogenous Cl- levels. Membrane potentials were corrected for liquid junction potentials. Cone resting potentials were found to average -46 mV. To measure ECl, we applied long depolarizing steps to activate the calcium-activated chloride current (ICl(Ca)) and then determined the reversal potential for the current component that was inhibited by the Cl- ...
This gene encodes a member of the bestrophin gene family. This small gene family is characterized by proteins with a highly conserved N-terminus with four to six transmembrane domains. Bestrophins may form chloride ion channels or may regulate voltage-gated L-type calcium-ion channels. Bestrophins are generally believed to form calcium-activated chloride-ion channels in epithelial cells but they have also been shown to be highly permeable to bicarbonate ion transport in retinal tissue. Mutations in this gene are responsible for juvenile-onset vitelliform macular dystrophy (VMD2), also known as Best macular dystrophy, in addition to adult-onset vitelliform macular dystrophy (AVMD) and other retinopathies. Alternative splicing results in multiple variants encoding distinct isoforms ...
TY - JOUR. T1 - Apical membrane chloride channels in a colonic cell line activated by secretory agonists. AU - Halm, D. R.. AU - Rechkemmer, G. R.. AU - Schoumacher, Robert. AU - Frizzell, R. A.. PY - 1988/1/1. Y1 - 1988/1/1. N2 - We characterized the anion channel responsible for the increase in apical membrane Cl secretion using a model salt-secreting epithelium, the T84 colonic cell line. The adenosine 3,5-cyclic monophosphate (cAMP)-mediated secretagogues, prostaglandin E2, forskolin, and 8-bromo-cAMP, evoked activity of an outwardly rectifying Cl channel in previously quiet cell-attached membrane patches. The channel remained active in excised, inside-out membranes, where its single-channel conductance was 40-45 pS at 0 mV with 160 mM NaCl in pipette and bath. Selectivities were P(Cl)/P(Na) = 50 and for halides I(1.8)/Br(1.4)/Cl(1.0)/F(0.4). This halide sequence illustrates that the ability of various anions to undergo transepithelial secretion is determined by the selectivity of the ...