cholinergic receptor nicotinic gamma subunit
The CHRNG gene provides instructions for making the gamma (γ) protein component (subunit) of the acetylcholine receptor (AChR) protein. The AChR protein is found in the membrane of skeletal muscle cells and is critical for signaling between nerve and muscle cells. Signaling between these cells is necessary for movement. The AChR protein consists of five subunits, each of which is produced from a different gene. The subunits are assembled into the AChR protein in the endoplasmic reticulum, a cell structure involved in protein processing and transport, before being transported to the cell membrane. The γ subunit is found only in the fetal AChR protein. At about the thirty-third week of pregnancy, the γ subunit is replaced by the epsilon (ε) subunit, which is produced by the CHRNE gene, to form the adult AChR protein.
At least 14 mutations in the CHRNG gene have been found to cause multiple pterygium syndrome, a condition characterized by webbing of the skin (pterygium) and a lack of muscle movement (akinesia) before birth. These mutations include replacing, adding, or deleting DNA building blocks (nucleotides). CHRNG gene mutations result in an impaired or missing γ subunit. The severity of the CHRNG gene mutation influences the severity of the condition. Typically, mutations that prevent the production of any γ subunit will result in lethal multiple pterygium syndrome, which is fatal before birth, while mutations that allow the production of some γ subunit will lead to the milder form of this condition called multiple pterygium syndrome, Escobar type. A shortage of a functional γ subunit prevents the fetal AChR protein from being assembled or properly placed in the muscle cell membrane. As a result, the fetal AChR protein cannot function and the communication between nerve and muscle cells in the developing fetus is impaired. A lack of signaling between nerve and muscle cells leads to akinesia and pterygium before birth, and many of the other signs and symptoms of multiple pterygium syndrome.
- acetylcholine gamma muscle receptor subunit
- acetylcholine receptor subunit gamma
- acetylcholine receptor, muscle, gamma subunit
- cholinergic gamma nicotinic receptor
- cholinergic receptor, nicotinic gamma
- cholinergic receptor, nicotinic, gamma
- cholinergic receptor, nicotinic, gamma (muscle)
- cholinergic receptor, nicotinic, gamma polypeptide
- Molecular Biology of the Cell (fourth edition, 2002): The Acetylcholine Receptors at the Neuromuscular Junction Are Transmitter-gated Cation Channels
- Molecular Cell Biology (fourth edition, 2000): All Five Subunits in the Nicotinic Acetylcholine Receptor Contribute to the Ion Channel
- Molecular Cell Biology (fourth edition, 2000): Signals From the Motor Neuron Regulate the Expression and Localization of the Acetylcholine Receptor (AChR) (figure)