 This contrasts with two-pore-domain potassium channels, which confusingly have only "one" pore and were named for the fact that each subunit has two P (pore) domains in its primary sequence.Although much is left to be discovered about TPC function, they have been extensively studied thus far.Many questions have been raised about the specific function of TPC channels, as well as the ions and molecules that appear to be most closely affiliated with these channels.