4BOR: The Structure And Super-organization Of Acetylcholine Receptor-rapsyn Complexes Class D

Proc. Natl. Acad. Sci. U. S. A. (2013) 110 p.10622-10627
The scaffolding protein at the neuromuscular junction, rapsyn, enables clustering of nicotinic acetylcholine receptors in high concentration and is critical for muscle function. Patients with insufficient receptor clustering suffer from muscle weakness. However, the detailed organization of the receptor-rapsyn network is poorly understood: it is unclear whether rapsyn first forms a wide meshwork to which receptors can subsequently dock or whether it only forms short bridges linking receptors together to make a large cluster. Furthermore, the number of rapsyn-binding sites per receptor (a heteropentamer) has been controversial. Here, we show by cryoelectron tomography and subtomogram averaging of Torpedo postsynaptic membrane that receptors are connected by up to three rapsyn bridges, the minimum number required to form a 2D network. Half of the receptors belong to rapsyn-connected groups comprising between two and fourteen receptors. Our results provide a structural basis for explaining the stability and low diffusion of receptors within clusters.
PDB ID: 4BORDownload
MMDB ID: 153314
PDB Deposition Date: 2013/5/22
Updated in MMDB: 2017/08
Experimental Method:
electron microscopy
Resolution: 42  Å
Source Organism:
Similar Structures:
Biological Unit for 4BOR: pentameric; determined by software (PISA)
Molecular Components in 4BOR
Label Count Molecule
Proteins (5 molecules)
Acetylcholine Receptor Subunit Alpha
Molecule annotation
Acetylcholine Receptor Beta Subunit
Molecule annotation
Acetylcholine Receptor Delta Subunit
Molecule annotation
Acetylcholine Receptor Gamma Subunit
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB