ClC - Chloride Carrier/Channel
Family:
The Chloride Carrier/Channel Family is a large but poorly understood family consisting of several hundred sequenced proteins from bacteria and eucaryotes. Although structurally similar, the individual proteins act either as chloride channels or as chloride/proton exchangers. Most CIC proteins are located in the plasma membrane, but several are predominantly in intracellular membranes.
Subgroups:
The mammalian CLC family contains 9 members, four of them (CIC-1, ClC-2, ClC-Ka, and ClC-Kb) are located on the plasma membrane where they act as chloride ion channels whereas the remaining five are located in intracellular organelles (CIC-3-7) and are chloride-proton exchangers. There is also a wide variety of bacterial CLC types.
Topology:
The structures of two bacterial and one eukaryotic ClC proteins have been reported so far. CLS subunits have a complex topology of up to 18 transmembrane segments and form homodimers. However, each of the identical subunits contributes an individually functional ion transport pathway.
Function:
ClC Cl- channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis.1
1. Saier Lab. Group, Transporter Classification Database
Data and Applications (Exchanger)
ClC - Proteoliposomes with different lipid-to-protein ratios
SURFE2R N1 data and applications:
We tested proteoliposomes with different densities of reconstituted ClC protein for their signal-to-noise ratios and compared the obtained signal amplitudes with a negative control: liposomes without reconstituted protein.
ClC - Inward and outward directed chloride flux
SURFE2R N1 data and applications:
According to the transport direction of 2Cl-/1H+ exchange, we observed positive (Cl- efflux) or negative (Cl- influx) transient currents.
ClC - Inhibition with OADS
SURFE2R N1 data and applications:
We investigated the effect of the specific ClC inhibitor OADS on the transport activity of ClC and its reversibility.
ClC - EC50 for inward and outward directed chloride flux
SURFE2R N1 data and applications:
We determined EC50 and relative Vmax for Cl- in an Cl-/H+ exchange assay for both transport directions and found a slight asymmetry in transporter kinetics.
Data and Applications (Ion Channels)
ClC-1 – Inhibition by 9-AC
SyncroPatch 384i data and applications:
Cells were kindly provided by Charles River.
Tail currents of ClC-1 expressed in CHO cells were inhibited by increasing concentration of 9-AC. A single concentration of 9-AC was added to each well and the concentration response curve constructed over multiple wells. The IC50 was calculated to be 6.3 µM for an average of 352 wells. The average current traces are also shown.
ClC-1 - Current-voltage plot
SyncroPatch 384i data and applications:
Cells were kindly provided by Charles River.
Activation of hClC-1 tail currents expressed in CHO cells recorded on the SyncroPatch 384i. A pre-pulse voltage step to +60 mV was followed by voltage steps from -120 mV to +80 mV for 300 ms (increasing in 20 mV steps) and the tail current was measured at the subsequent step to -100 mV. Out of a possible 384 wells, all 384 wells were used for the IV analysis
Posters
Publications
2019 - Structure of the human ClC-1 chloride channel
Port-a-Patch, 
Vesicle Prep Pro and 
Orbit mini publication in PLOS Biology (2019)
Authors:
Wang K., Preisler, SS, Zhang, L., Cui, Y., Missel, JW., Grønberg C., Gotfryd, K., Lindahl E., Andersson, M., Calloe, K., Egea P.F., Klaerke D.A., Pusch M., Pedersen P.A., Zhou, Z.H., Gourdon, P.
2013 - Functional characterization of a ClC transporter by solid-supported membrane electrophysiology
SURFE²R-technology (custom-built system) publication in Journal of General Physiology (2013)
Authors:
Garcia-Celma J., Szydelko A., Dutzler R.
2010 - The G215R Mutation in the Cl−/H+-Antiporter ClC-7 Found in ADO II Osteopetrosis Does Not Abolish Function but Causes a Severe Trafficking Defect
SURFE²R ONE (a predecessor model of SURFE²R N1) publication in PLoS ONE (2010)
Authors:
Schulz P., Werner J., Stauber T., Henriksen K., Fendler K.