<unk> s are a class of transmembrane ion channels that are activated by changes in electrical potential difference near the channel; these types of ion channels are especially critical in neurons, but are common in many types of cells.  All<unk> <unk>  contain repeating sequences of arginine that are responsible for the charged portion of the domain.
They have a crucial role in excitable neuronal and muscle tissues, allowing a rapid and coordinated depolarization in response to triggering<unk>  change. Found along the axon and at the synapse,<unk> s directionally propagate electrical signals.
Voltage-gated ion channel
Cyclic nucleotide-gated ion channel
Light-gated ion channel
Voltage-dependent calcium channel
Ion transporter
Ion channel
Calcium channel
Chloride channel