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.