CHRND

CHRND is a gene that encodes the delta subunit of the nicotinic acetylcholine receptor. This receptor is a pentameric transmembrane protein that is responsible for mediating the fast signal transmission at the neuromuscular junction. The delta subunit, along with the alpha, beta, and epsilon (or gamma in fetal muscle) subunits, forms the functional core of the receptor.

Structure

The CHRND gene is located on the long arm of chromosome 2 (2q37.1). It spans approximately 8 kilobases and contains 10 exons. The encoded protein is composed of 520 amino acids and has a molecular weight of approximately 57 kDa. The protein is organized into a large extracellular domain, four transmembrane domains, and a small intracellular loop.

Function

The delta subunit of the nicotinic acetylcholine receptor, encoded by the CHRND gene, plays a crucial role in the function of the receptor. It contributes to the formation of the ligand-binding site and is involved in the gating mechanism of the receptor. Upon binding of acetylcholine, the receptor undergoes a conformational change that allows the influx of sodium ions, leading to depolarization of the muscle cell and subsequent muscle contraction.

Clinical significance

Mutations in the CHRND gene have been associated with several forms of congenital myasthenic syndrome (CMS), a group of disorders characterized by muscle weakness and fatigue. These mutations can lead to a decrease in the number of functional receptors at the neuromuscular junction, impairing signal transmission and leading to the symptoms of CMS.

See also

• CHRNG
• CHRNE
• CHRNB1
• Congenital myasthenic syndrome