Stable and functional expression of the CIC-3 chloride channel in somatic cell lines.
The CIC family is the superfamily of voltage-gated Cl- channels. Although the CIC channels expressed in Xenopus oocytes have been characterized, their channel properties are still poorly understood. We recently cloned a unique member of the CIC family, CIC-3, that is expressed abundantly in neurons. Its channel activity was regulated by phorbol esters. Now, we have established a stably transfected somatic cell line expressing functional CIC-3 channels and examined the CIC-3 single-channel current by patch-clamp techniques. In inside-out patches from the stably transfected cells, a rise of bath Ca2+ concentration in the physiological range of intracellular Ca2+ concentrations inhibited the CIC-3 single-channel currents. This inhibition by Ca2+ was independent of phosphorylation and ATP. Thus, the CIC-3 channel is a Ca(2+)-sensitive Cl- channel localized in neuronal cells, and its Ca2+ sensitivity implies a physiological role in neuronal functions.
Kawasaki
M
M
Second Department of Internal Medicine, School of Medicine, Tokyo Medical and Dental University, Japan.
Suzuki
M
M
Uchida
S
S
Sasaki
S
S
Marumo
F
F
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D018118:Chloride Channels / Q000235:genetics* / Q000502:physiology; D006224:Cricetinae; D015870:Gene Expression; D015640:Ion Channel Gating / Q000187:drug effects; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D018118:Chloride Channels; D012333:RNA, Messenger; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate; D013755:Tetradecanoylphorbol Acetate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D002118:Calcium