Multiple potassium and chloride channels in the human colon carcinoma cell line SW1116.
SW1116 cells have a profound capacity for secreting mucin molecules bearing the Lewisa epitope. Mucin molecules with the same epitope have been found to be elevated in the serum of patients with cystic fibrosis, a disease with defective ion channels. We therefore decided to study ion channels in this cell line. In the present work, we report the presence of two K(+)-channels and two Cl(-)-channels in the apical membrane of SW1116 cells. One of the K(+)-channels has a large conductance (approximately 278 pS), anomalous rectifying properties, and is inactivated rapidly. The second type exhibited a linear I/V curve (19 pS), was voltage insensitive and inactivation was not observed. In cell-attached patches, spontaneous openings of chloride channels were seen with higher frequency than previously reported in other colon carcinoma cell lines or airway epithelial cells. Inside-out experiments allowed identification of two different Cl(-)-channels (Cl(-)-1 and Cl(-)-2). Both exhibited rectification, but in opposite directions, and both were insensitive to NIPAB.
Etcheberrigaray
R
R
Neural Systems Section, NINDS, National Institutes of Health, Bethesda, MD 20892.
Yedgar
S
S
Rojas
E
E
Pollard
H B
HB
D018118:Chloride Channels; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000648:ultrastructure; D004553:Electric Conductivity; D006801:Humans; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism*; D008854:Microscopy, Electron; D009077:Mucins / Q000378:metabolism; D015221:Potassium Channels / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D018118:Chloride Channels; D008565:Membrane Proteins; D009077:Mucins; D015221:Potassium Channels