Phosphatase Inhibitor Calyculin A Activates TRPC2 Channels in Thyroid FRTL-5 Cells

We have previously shown that rat thyroid FRTL-5 cells express a calcium entry pathway regulated by a phosphatase. The nature of the calcium entry pathway is presently unknown. We have also shown that FRTL-5 cells express only the TRPC2 channel of the TRPC family of cation channels. In the present investigation we show, using pharmacological inhibitors, the measurement of sodium and calcium entry, stable TRPC2 knock-down cells, and transfection with a non-conducting form of TRPC2, that the calcium entry pathway regulated by a phosphatase is, in fact, the TRPC2 channel. Our data thus point to a novel mechanism by which the TRPC2 channels can be regulated.