Inhibition of chloride channel currents in A549 cells by S2 protein of SARS coronavirus

Objective To study the effect of S2-protein from SARS coronavirus on the chloride channel currents in A549 cells and its possible cellular mechanisms. Methods The chloride channel currents were recorded in cultured A549 cells by using the whole-cell mode of patch clamp techniques. The experiments were divided into four groups: Control group: chloride channel currents were recorded in untreated A549 cells; S2 protein group: currents were recorded in A549 cells treated with S2 protein (final concentration 50?g/ml); calphostin C + S2 protein group: the effect of S2 protein on the currents in A549 cells pretreated with calphostin C (0.1mmol/L) for 10 minutes; SB203580+S2 protein group: the effect of S2 protein on the currents was examined with the solution containing SB203580 (20?mol/L). Results The currents of chloride channel in normal A549 cells showed outwardly rectifying properties and were insensitive to both TEA and amiloride, but were significantly inhibited both by SITS and DIDS (P