Voltage-gated potassium channels play an essential role in controlling cellular excitability in the nervous system. They regulate a variety of properties including membrane potential as well as the frequency and structure of action potentials. KCNH1 (potassium voltage-gated channel, subfamily H (eag-related), member 1), also known as ether-a-go-go potassium channel 1, voltage-gated potassium channel subunit Kv10.1, EAG, EAG1 or h-eag, is a 989 amino acid multi-pass membrane protein belonging to the potassium channel family and H (Eag) subfamily. KCNH1 is highly expressed in myoblasts and brain, forms two alternatively spliced isoforms and exists as a pore-forming (alpha) subunit of a voltage-gated non-inactivating delayed rectifier potassium channel. Encoded by a gene located on human chromosome 1, KCNH1 forms a heteromultimer with KCNH5 and also interacts with ALG10.