ATP1A3

The ATP1A3 gene provides instructions for making one part (the alpha-3 subunit) of a protein known as Na+/K+ ATPase or the sodium pump. This protein uses energy from a molecule called adenosine triphosphate (ATP) to transport charged atoms (ions) into and out of cells. Specifically, it pumps sodium ions (Na+) out of cells and potassium ions (K+) into cells.

Na+/K+ ATPase is critical for the normal function of nerve cells (neurons) in the brain. The movement of sodium and potassium ions helps regulate the electrical activity of these cells and plays an important role in the signaling process that controls muscle movement. The activity of Na+/K+ ATPase also helps regulate cell size (volume).

Additionally, Na+/K+ ATPase helps regulate a process called neurotransmitter reuptake. Neurotransmitters are chemicals that transmit signals from one neuron to another. After a neurotransmitter has had its effect, it must be removed quickly from the space between the neurons. The reuptake of neurotransmitters is carefully controlled to ensure that signals are sent and received accurately throughout the nervous system.

rapid-onset dystonia parkinsonism - caused by mutations in the ATP1A3 gene

At least nine mutations in the ATP1A3 gene have been identified in individuals and families with rapid-onset dystonia parkinsonism. Most of these mutations change single protein building blocks (amino acids) in the alpha-3 subunit of Na+/K+ ATPase. Changes in the protein's structure can reduce its activity or make it unstable. Studies suggest that the defective Na+/K+ ATPase is unable to transport sodium ions normally, which disrupts the electrical activity of neurons in the brain. However, it is unclear how a malfunctioning Na+/K+ ATPase causes the movement abnormalities characteristic of rapid-onset dystonia parkinsonism.