Top ▲

Maxi chloride channel C

Unless otherwise stated all data on this page refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).

Overview

Click here for help

« Hide

Maxi Cl- channels are high conductance, anion selective, channels initially characterised in skeletal muscle and subsequently found in many cell types including neurones, glia, cardiac muscle, lymphocytes, secreting and absorbing epithelia, macula densa cells of the kidney and human placenta syncytiotrophoblasts [9]. The physiological significance of the maxi Cl- channel is uncertain, but roles in cell volume regulation and apoptosis have been claimed. Evidence suggests a role for maxi Cl- channels as a conductive pathway in the swelling-induced release of ATP from mouse mammary C127i cells that may be important for autocrine and paracrine signalling by purines [4,8]. A similar channel mediates ATP release from macula densa cells within the thick ascending of the loop of Henle in response to changes in luminal NaCl concentration [2]. A family of human high conductance Cl- channels (TTYH1-3) that resemble Maxi Cl- channels has been cloned [11], but alternatively, Maxi Cl- channels have also been suggested to correspond to the voltage-dependent anion channel, VDAC, expressed at the plasma membrane [1,5].

Channels and Subunits

709
Click here for help

Maxi Cl- C Show summary »


Target Id 709
Nomenclature Maxi Cl-
Previous and unofficial names High conductance anion channel | Volume- and voltage-dependent ATP-conductive large conductance (VDACL) anion channel
Activators
extracellular chlorpromazine
extracellular tamoxifen
cytosolic GTPγS
extracellular toremifene
extracellular triflupromazine
Endogenous channel blockers
intracellular arachidonic acid
Channel blockers
DIDS pIC50 4.4 [10]
extracellular Zn2+ pIC50 4.3 [6]
NPPB pIC50 3.8 [10]
extracellular Gd3+
diphenylamine-2-carboxylic acid
SITS
Functional characteristics γ = 280-430 pS (main state);
permeability sequence, I > Br > Cl > F > gluconate (PCIPCl = ~1.5);
ATP is a voltage dependent permeant blocker of single channel activity (PATP/PCl = 0.08–0.1); channel activity increased by patch-excision; channel opening probability (at steady-state) maximal within approximately ± 20 mV of 0 mV, opening probability decreased at more negative and (commonly) positive potentials yielding a bell-shaped curve; channel conductance and opening probability regulated by annexin 6
Comment Maxi Cl- is also activated by G protein-coupled receptors and cell swelling. Tamoxifen and toremifene are examples of triphenylethylene anti-oestrogens

Comments

Click here for help

Show »

References

Click here for help

Show »

How to cite this family page

Database page citation:

Maxi chloride channel. Accessed on 01/12/2021. IUPHAR/BPS Guide to PHARMACOLOGY, http://www.guidetopharmacology.org/GRAC/FamilyDisplayForward?familyId=131.

Concise Guide to PHARMACOLOGY citation:

Alexander SPH, Mathie A, Peters JA, Veale EL, Striessnig J, Kelly E, Armstrong JF, Faccenda E, Harding SD, Pawson AJ, Sharman JL, Southan C, Davies JA; CGTP Collaborators. (2019) The Concise Guide to PHARMACOLOGY 2019/20: Ion channels. Br J Pharmacol. 176 Issue S1: S142-228.