TRPC1 and idiopathic pulmonary arterial hypertension: While in previous studies proliferation of PASMCs in TRPC1−/− and TRPC1/6−/− mice was reduced (Malczyk et al., 2013), contradictory findings investigating TRPC6 exist: although it seems that knockdown of TRPC6 in IPAH patients led to a reduced proliferation of PASMCs (Yu et al., 2004) TRPC6 is not involved in PASMC proliferation in mice (Malczyk et al., 2013).