Selective inhibition of KCa3.1 channels in THP-1 cells by ENV59-GP3
We next examined the direct effect of the ENV59-GP3 peptide on the essentially pure KCa3.1 current (Figure 4B-C) at -40mV in THP-1 cells (Figure 4B). ENV59-GP3 peptide was applied at concentrations relevant for its immunosuppressive effects (Figure 3C) and, as clearly shown, it reversibly inhibited the -40mV current component, which was formally identified as being KCa3.1 by the subsequent application of NS6180. Furthermore, the ENV59-GP3 peptide-like NS6180-did not exert a measurable effect on the voltage dependent current component at positive potentials. Hence the effect seems selective for the KCa3.1 channel over Kv channels in THP-1 cells.