ATP1A2

ATP1A2

ATP1A2 is a gene that encodes the alpha-2 subunit of the Na+/K+ ATPase enzyme, which is crucial for maintaining the electrochemical gradients of sodium and potassium ions across the plasma membrane. This enzyme is essential for various physiological processes, including neuronal activity, muscle contraction, and cardiac function.

Function

The Na+/K+ ATPase, also known as the sodium-potassium pump, is an integral membrane protein that actively transports sodium ions out of the cell and potassium ions into the cell, against their concentration gradients. The ATP1A2 gene specifically encodes the alpha-2 subunit, which is one of the four alpha subunit isoforms. The alpha-2 subunit is predominantly expressed in astrocytes, skeletal muscle, and cardiac muscle.

Clinical Significance

Mutations in the ATP1A2 gene have been associated with several neurological disorders, including familial hemiplegic migraine (FHM) and alternating hemiplegia of childhood (AHC). These conditions are characterized by episodes of hemiplegia, seizures, and other neurological symptoms.

Familial Hemiplegic Migraine

Familial hemiplegic migraine is a rare form of migraine with aura, where patients experience temporary paralysis on one side of the body. Mutations in ATP1A2 disrupt the normal function of the Na+/K+ ATPase, leading to altered neuronal excitability and increased susceptibility to migraine attacks.

Alternating Hemiplegia of Childhood

Alternating hemiplegia of childhood is a rare neurological disorder that presents in infancy or early childhood. It is characterized by recurrent episodes of hemiplegia, developmental delay, and movement disorders. ATP1A2 mutations can impair the pump's ability to regulate ion gradients, contributing to the pathophysiology of AHC.

Expression

The ATP1A2 gene is expressed in various tissues, with high levels in the central nervous system, heart, and skeletal muscle. The expression pattern of ATP1A2 is crucial for its role in maintaining ion homeostasis in these tissues.

Structure

The Na+/K+ ATPase is a heterodimeric enzyme composed of an alpha subunit and a beta subunit. The alpha-2 subunit encoded by ATP1A2 contains ten transmembrane domains and is responsible for the enzyme's catalytic activity. It binds and hydrolyzes ATP to drive the active transport of sodium and potassium ions.

See Also

• Na+/K+ ATPase
• Ion channel
• Migraine
• Neurological disorder

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