What is the role of the acetylcholine receptor for myasthenia gravis (MG)?

Updated: Aug 27, 2018
  • Author: Abbas Jowkar, MD; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Answer

AChR is an ionotropic ligand-gated transmembrane receptor channel. It is a quaternary glycoprotein structure with 5 subunits surrounding a central cation channel with negatively charged inner wall. In the adult or "innervated" form of AChR (2α1ß1δ1ε) and in the fetal or "denervated" form of AChR (2α1ß1δ1γ). It has a half-life of 8–11 days. [17] These subunits are homologous across different species, suggesting that the encoding genes evolved from a common ancestral gene. The AChR subunits are arranged in a circle, spanning the membrane forming a central opening that acts as an ion channel (see the image below). Each AChR subunit is composed of four transmembrane domains (M1–M4).

Acetylcholine receptor. Note 5 subunits, each with Acetylcholine receptor. Note 5 subunits, each with 4 membrane-spanning domains forming a rosette with a central opening. The central opening acts as an ion channel.

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