2D57: Double Layered 2D Crystal Structure of Aquaporin-4 (Aqp4m23) at 3.2 a Resolution by Electron Crystallography

Aquaporin-4 (AQP4) is the predominant water channel in the mammalian brain and an important drug target for treatment of cerebral edema, bipolar disorder and mesial temporal lobe epilepsy. We determined the AQP4 structure by electron crystallography of double-layered, two-dimensional (2D) crystals. The structure allows us to discuss how the expression ratio between the long and short AQP4 splicing variant can determine the size of in vivo orthogonal arrays. Furthermore, AQP4 contains a short 3(10) helix in an extracellular loop, which mediates weak but specific interactions between AQP4 molecules in adjoining membranes. This finding suggests a previously unexpected role for AQP4 in cell adhesion. This notion was corroborated by expression of AQP4 in L-cells, which resulted in clustering of the cells. Our AQP4 structure thus enables us to propose models for the size regulation of orthogonal arrays and channel-mediated cell adhesion.
PDB ID: 2D57Download
MMDB ID: 37270
PDB Deposition Date: 2005/10/29
Updated in MMDB: 2012/11 
Experimental Method:
electron crystallography
Resolution: 3.2  Å
Source Organism:
Similar Structures:
Biological Unit for 2D57: tetrameric; determined by author and by software (PISA,PQS)
Molecular Components in 2D57
Label Count Molecule
Proteins (4 molecules)
Aquaporin-4(Gene symbol: Aqp4)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB