3J41

Pseudo-atomic model of the Aquaporin-0/Calmodulin complex derived from electron microscopy

Summary for 3J41

• Entry DOI: 10.2210/pdb3j41/pdb
• Related: 1NWD 2B6P
• EMDB information: 5679
• Descriptor: Lens fiber major intrinsic protein, Calmodulin, CALCIUM ION (3 entities in total)
• Functional Keywords: calcium regulation, water channel, membrane protein complex, transport protein-calcium binding complex, transport protein/calcium binding
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 6
• Total formula weight: 147005.17

Authors

Reichow, S.L.,Clemens, D.M.,Freites, J.A.,Nemeth-Cahalan, K.L.,Heyden, M.,Tobias, D.J.,Hall, J.E.,Gonen, T. (deposition date: 2013-05-31, release date: 2013-07-31, Last modification date: 2024-02-21)

Primary citation

Reichow, S.L.,Clemens, D.M.,Freites, J.A.,Nemeth-Cahalan, K.L.,Heyden, M.,Tobias, D.J.,Hall, J.E.,Gonen, T.
Allosteric mechanism of water-channel gating by Ca(2+)-calmodulin.
Nat.Struct.Mol.Biol., 20:1085-1092, 2013

PubMed Abstract: Calmodulin (CaM) is a universal regulatory protein that communicates the presence of calcium to its molecular targets and correspondingly modulates their function. This key signaling protein is important for controlling the activity of hundreds of membrane channels and transporters. However, understanding of the structural mechanisms driving CaM regulation of full-length membrane proteins has remained elusive. In this study, we determined the pseudoatomic structure of full-length mammalian aquaporin-0 (AQP0, Bos taurus) in complex with CaM, using EM to elucidate how this signaling protein modulates water-channel function. Molecular dynamics and functional mutation studies reveal how CaM binding inhibits AQP0 water permeability by allosterically closing the cytoplasmic gate of AQP0. Our mechanistic model provides new insight, only possible in the context of the fully assembled channel, into how CaM regulates multimeric channels by facilitating cooperativity between adjacent subunits.

PubMed: 23893133
DOI: 10.1038/nsmb.2630

Experimental method

ELECTRON MICROSCOPY (25 Å)