Enables cAMP binding activity; cation channel activity; and identical protein binding activity. Involved in cellular response to cAMP and potassium ion transmembrane transport. Acts upstream of or within apical protein localization and retinal cone cell development. Located in axon and dendrite. Is integral component of plasma membrane. Is expressed in brain; heart; and heart ventricle. Used to study sick sinus syndrome. Human ortholog(s) of this gene implicated in developmental and epileptic encephalopathy 24 and generalized epilepsy with febrile seizures plus 10. Orthologous to human HCN1 (hyperpolarization activated cyclic nucleotide gated potassium channel 1). [provided by Alliance of Genome Resources, Apr 2022]