A5056096431- Ion channel regulation and function
- Ion Transport and Channel Regulation
- Neuroscience and Neuropharmacology Research
- Cardiac electrophysiology and arrhythmias
- Ion Channels and Receptors
- Cystic Fibrosis Research Advances
- Electrochemical Analysis and Applications
- Nicotinic Acetylcholine Receptors Study
- Aldose Reductase and Taurine
- Retinal Development and Disorders
- Lipid Membrane Structure and Behavior
- Helminth infection and control
- Asthma and respiratory diseases
- Neonatal Respiratory Health Research
- Receptor Mechanisms and Signaling
- Magnesium in Health and Disease
- Neuroscience and Neural Engineering
- Cellular transport and secretion
- Parasite Biology and Host Interactions
- Neuroscience of respiration and sleep
- Connexins and lens biology
- Climate variability and models
- Gestational Diabetes Research and Management
- Marine and coastal plant biology
- Arsenic contamination and mitigation
Centro de Estudios Científicos
2013-2024
San Sebastián University
2023-2024
University of Talca
2016
Inserm
2014
Sorbonne Université
2014
Instituto de Fomento Pesquero
2014
Angelina College
2010
University of Concepción
1993-2007
University of Chile
1997-2001
Johns Hopkins University
1995-1998
The molecular identity of K+channels involved in Ehrlich cell volume regulation is unknown. A background K+ conductance activated by swelling and also modulated extracellular pH. These characteristics are most similar to those newly emerging TASK (TWIK-related acid-sensitive channels)-type two pore-domain channels. mTASK-2, but not TASK-1 or -3, present cells mouse kidney tissue from where the full coding sequences were obtained. Heterologous expression mTASK-2 cDNA HEK-293 generated...
Cystic fibrosis (CF) is a lethal inherited disease that results from abnormal chloride conduction in epithelial tissues. ClC-2 channels are expressed epithelia affected by CF and may provide key “alternative” target for pharmacotherapy of this disease. To explore possibility, the expression level was genetically manipulated airway cells derived cystic patient (IB3-1). Whole-cell patch-clamp analysis overexpressing identified hyperpolarization-activated Cl − currents (HACCs) displayed time-...
The Cl– channel ClC-2 is expressed in transporting epithelia and has been proposed as an alternative route for efflux that might compensate the malfunction of CFTR cystic fibrosis. There controversy concerning cellular membrane location ClC-2, particularly intestinal tissue. aim this paper to resolve by immunolocalization studies using tissues from knockout animals control, ascertaining sorting model epithelial cells exploring possible molecular signals involved targeting. was exclusively...
Potassium channels share a common selectivity filter that determines the conduction characteristics of pore. Diversity in K+ is given by how they are gated open. TASK-2, TALK-1, and TALK-2 two-pore region (2P) KCNK open extracellular alkalinization. We have explored mechanism for this alkalinization-dependent gating using molecular simulation site-directed mutagenesis followed functional assay. show side chain single arginine residue (R224) near pore senses pH TASK-2 with an unusual pKa 8.0,...
TASK-2 (KCNK5 or K2P5.1) is a background K+ channel that opened by extracellular alkalinization and plays role in renal bicarbonate reabsorption central chemoreception. Here, we demonstrate addition to its regulation protons (pHo) gated open intracellular alkalinization. The following pieces of evidence suggest the gating process controlled pH (pHi) independent from under command pHo. It was not possible overcome closure acidification means mutant TASK-2-R224A lacks sensitivity pHo had...
Organic osmolyte and halide permeability pathways activated in epithelial HeLa cells by cell swelling were studied radiotracer efflux techniques single-cell volume measurements. The replacement of extracellular Cl- anions that are more permeant through the volume-activated channel, as indicated electrophysiological measurements, significantly decreased taurine efflux. In presence less-permeant anions, an increase was observed. Simultaneous measurement 125I, used a tracer for Cl-, [3H]taurine...
We have cloned a cDNA from the human epithelial cell line T84 whose predicted amino acid sequence shows 93.9% identity with rat CIC-2. Mapping by somatic hybrids and polymerase chain reaction localizes gene corresponding to this chromosome 3q26-qter. The major transcription start site assessed RNA primer extension is 100 nt upstream of putative translation initiation codon. Analysis 5′ flanking revealed high GC content lack common transcriptional elements such as TATA CCAAT boxes. Northern...
Functional and structural studies demonstrate that Cl − channels of the ClC family have a dimeric double‐barrelled structure, with each monomer contributing an identical pore. Single protopore gating is fast process dependent on interaction within selectivity filter in ClC‐0 has low temperature coefficient over 10°C range ( Q 10 ). A slow closes both protopores simultaneously, high , facilitated by extracellular Zn 2+ Cd abolished or markedly reduced mutation cysteine conserved ClC‐0, ‐1 ‐2....
The ClC-2 Cl- channel has been postulated to play a role in the inhibitory GABA response neurons or participate astrocyte-dependent extracellular electrolyte homeostasis. Three different mutations CLCN2 gene, encoding voltage-dependent homodimeric channel, have associated with idiopathic generalized epilepsy (IGE). We study their function vitro by patch clamp and confocal microscopy transiently transfected HEK-293 cells. A first mutation predicts premature stop codon (M200fsX231). An altered...
ClC-2 is a ubiquitously expressed, two-pore homodimeric Cl- channel opened by hyperpolarisation. Little known about its gating mechanisms. Crystallographic and functional studies in other ClC channels suggest that conserved glutamate residue carboxylate side-chain can close protopores interacting with Cl--binding site the pore. Competition for this thought to provide molecular basis extracellular Cl-. We now show depends upon intra- but not neutralisation of E217, homologous pore glutamate,...
The ClC transport protein family comprises both Cl(-) ion channel and H(+)/Cl(-) H(+)/NO(3)(-) exchanger members. Structural studies on a bacterial transporter reveal pore obstructed at its external opening by glutamate side-chain which acts as gate for passage in addition serves staging post H(+) exchange. This same conserved to regulate flow channels. activity of ClC-2, genuine channel, has biphasic response extracellular pH with activation moderate acidification followed abrupt closure...
TASK-2 (K2P5.1) is a two-pore domain K(+) channel belonging to the TALK subgroup of K2P family proteins. has been shown be activated by extra- and intracellular alkalinization. Extra- pH-sensors reside at arginine 224 lysine 245 might affect separate selectivity filter inner gates respectively. modulated changes in cell volume regulation direct G-protein interaction also proposed. Activation extracellular alkalinization associated with role kidney proximal tubule bicarbonate reabsorption,...
We identified two ClC-2 clones in a guinea pig intestinal epithelial cDNA library, one of which carries 30-bp deletion the NH 2 terminus. PCR using primers encompassing gave products that furthermore were amplified with specific confirming their authenticity. The corresponding genomic DNA sequence structure three exons and introns. An internal donor site occurring within accounts for deletion, consistent alternative splicing. Expression variants gpClC-2 gpClC-2Δ77–86 HEK-293 cells generated...
The principal function of the colon in fluid homeostasis is absorption NaCl and water. Apical membrane Na + channels, /H Cl − /HCO[Formula: see text] exchangers, have all been postulated to mediate entry into colonocytes. identity basolateral exit pathway for unknown. We previously demonstrated presence ClC-2 transcript guinea pig intestine. Now we explore more detail, tissue cellular distribution chloride channel distal by situ hybridization immunohistochemistry. patch-clamp technique was...
Kir7.1 is an inwardly rectifying K+ channel of the Kir superfamily encoded by kcnj13 gene. present in epithelial tissues where it colocalizes with Na+/K+-pump probably serving to recycle taken up pump. Human mutations affecting are associated retinal degeneration diseases. We generated a mouse lacking ablation Kcnj13 Homozygous mutant null mice die hours after birth and show cleft palate moderate retardation lung development. expressed epithelium covering palatal processes at time which...
Non‐Technical Summary High levels of oestrogen are known to cause fluid retention in fertile females. It is thought that the increase body volume necessary for proper implantation fertilised egg uterus. We show activity a potassium ion channel, which drives salt and water movement across cell membranes intestine, inhibited by this effect only found females maximal during peak phase oestrous cycle (when fertilization occur). These findings help us understand molecular mechanisms underlying...
K(+) channels share common selectivity characteristics but exhibit a wide diversity in how they are gated open. Leak K(2P) TASK-2, TALK-1 and TALK-2 open by extracellular alkalinization. The mechanism for this alkalinization-dependent gating has been proposed to be the neutralization of side chain single arginine (lysine TALK-2) residue near pore which occurs with unusual pK(a) 8.0. We now corroborate hypothesis transplanting TASK-2 pH (pH(o)) sensor background pH(o)-insensitive TASK-3...
Aquaporin-2 (AQP-2) is the vasopressin-regulated water channel expressed in apical membrane of principal cells collecting duct and involved urinary concentrating mechanism. In rat distal colon, vasopressin stimulates absorption through an unknown With hypothesis that AQP-2 could contribute to this effect, we studied its presence colonic epithelium. We used RT-PCR, situ hybridization, immunoblotting, immunocytochemistry probe for expression. An amplicon was obtained RT-PCR colon epithelium...
ClC-2, a chloride channel widely expressed in mammalian tissues, is activated by hyperpolarisation and extracellular acidification. Deletion of amino acids 16-61 rat ClC-2 abolishes voltage pH dependence two-electrode voltage-clamp experiments amphibian oocytes. These results have been interpreted terms ball-and-chain type mechanism which the N-terminus would behave as ball that removed from an inactivating site upon hyperpolarisation. We now report whole-cell patch-clamp measurements cells...