Proteolytic modification of swelling-activated Cl- current in LNCaP prostate cancer epithelial cells.
The effects of intracellular application of trypsin on the Cl- current induced by hypotonic cell swelling (I(Cl,swell)) in human prostate cancer epithelial cells (LNCaP) was studied using the patch-clamp technique. In cells predialyzed with 1 mg/mL trypsin, I(Cl,swell)) developed and diminished in response to the application and withdrawal of hypotonic solution about three times faster than that in control cells. In trypsin-infused cells, I(Cl,swell)) also had about twofold higher current density and displayed considerably slowed voltage-dependent inactivation, which was quite pronounced in control cells at potentials above +60 mV. Trypsin-induced modification of I(Cl,swell)) could be prevented by coinfusion of 10 mg/mL soybean trypsin inhibitor, suggesting that proteolytic cleavage of essential intracellular structural domains of the I(Cl,swell))-carrying volume-regulated anion channel (VRAC) was responsible for this functional modification. The effect of trypsin was not dependent on the presence of intracellular ATP. We conclude that VRACs, similarly to voltage-gated Na+, K+, and Cl- channels, possess intracellular inactivation domain(s) subjected to proteolytic cleavage that may function in conformity with the classical "ball-and-chain" inactivation model.
Vitko
Yulia V
YV
Bogomoletz Institute of Physiology, Kiev, Ukraine.
Pogorelaya
Nelli H
NH
Prevarskaya
Natalia
N
Skryma
Roman
R
Shuba
Yaroslav M
YM
D048429:Cell Size / Q000502:physiology; D018118:Chloride Channels / Q000378:metabolism*; D002713:Chlorine / Q000378:metabolism*; D004594:Electrophysiology; D004848:Epithelium / Q000473:pathology*; D006801:Humans; D007038:Hypotonic Solutions / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D009995:Osmosis / Q000502:physiology; D018408:Patch-Clamp Techniques; D011471:Prostatic Neoplasms / Q000473:pathology*; D014357:Trypsin / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D018118:Chloride Channels; D007038:Hypotonic Solutions; D002713:Chlorine; D014357:Trypsin