voltage-gated potassium channel complex HCN channel complex potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 1 complex GO:1990759 HCN4 channel complex potassium/sodium hyperpolarization-activated channel 3 complex GO:0098855 GO:1990746 potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 4 tetramer A cation ion channel with a preference for K+ over Na+ ions, which is activated by membrane hyperpolarization, and consists of a tetramer of HCN family members. Some members of this family (HCN1, HCN2 and HCN4) are also activated when cAMP binds to their cyclic nucleotide binding domain (CNBD). Channel complexes of this family play an important role in the control of pacemaker activity in the heart. HCN3 channel complex cellular_component K/Na hyperpolarization-activated channel 3 complex potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 2 tetramer HCN2 channel complex potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 4 complex K/Na hyperpolarization-activated cyclic nucleotide-gated channel complex K/Na hyperpolarization-activated cyclic nucleotide-gated channel 1 complex K/Na hyperpolarization-activated cyclic nucleotide-gated channel 4 complex potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 2 complex potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel complex HCN1 channel complex K/Na hyperpolarization-activated cyclic nucleotide-gated channel 2 complex