Sandbox Reserved 1100

This Sandbox is Reserved from 25/11/2019, through 30/9/2020 for use in the course "Structural Biology" taught by Bruno Kieffer at the University of Strasbourg, ESBS. This reservation includes Sandbox Reserved 1091 through Sandbox Reserved 1115.

To get started: Click the edit this page tab at the top. Save the page after each step, then edit it again. show the Scene authoring tools, create a molecular scene, and save it. Copy the green link into the page. Add a description of your scene. Use the buttons above the wikitext box for bold, italics, links, headlines, etc. More help: Help:Editing

The AdipoR1 receptor

spinqualitylabelsall models Caption for this structure Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D FUNCTION The protein adiponectin receptor 1 is one of the two receptors for the hormone called adiponectin. The adiponectin is an hormone, and more precisely an adipokine , present in the blood at high concentration, approximatively 0,01 % of the total amount of proteins in plasma The Adiponectin receptor 1 contains seven transmembrane helices linked thanks to three extracellular loops and three intracellular loops. The helix I is formed by the residues 135 to 157, helix II by the residues 169 to 192, the helix III by the residues 198 to 227, the helice IV by the residues 232 to 252, the helix V by the residues 264 to 288 heliX VI by the residues 305 to 319 and the helix VII by the residues 336 to 364 .Besides, the helix III and VII are longer than the other helices. These seven transmembrane helices have a clockwise circular specific organisation (from helix I to helix VII) and form a bundle. Concerning the extracellular faces, the three extracellular loops which connect the transmembrane helices are exposed and it is the same for the C-terminus domain. Besides, helix III and the VII are longer than the other helices and as a result the C-terminus domain two turns of the VII are exposed too. In the middle of the seven transmembrane helices there is a large internal cavity where a zinc-binding site can be found. This cavity located from the cytoplasmic surface to the middle of the outer lipid layer of the membrane has small openings between the helix V and VI, and between the helice IV and VI. It has been assumed that these openings are involved in the entrance and exit of both substrate and product. In this cavity, there is a zinc ion which is coordinated thanks to three histidine residues. These three histidine residues are H191 in the helix II, H337 and H341 in the helix VII. As a result, the zinc ion is in the intracellular layer of the membrane, in the neighbourhood of 4° deep from the inner surface of the plasma membrane. Thanks to its tetrahedral coordination, this zinc ion binds the helix II, III and VII together. The adiponectin-stimulated AMPK phosphorylation doesn’t directly require the zinc binding site, nevertheless it has been supposed that the zinc ion allows a stabilizing effect. AdipoR1 has the capacity to form oligomers. Indeed in living cell both monomers and oligomers are present. A specific motif was identified to contribute to the AdipoR1 dimerization: it is the motif GxxxG in the transmembrane helix V. Besides, the dimerization of AdipoR1 is also regulated. This dimerization is inhibited by the fixation of the full-length adiponectin while the globular adiponectin has any impact on the dimerization level of the AdipoR1 receptor. Thanks to mutant experiment, it can be supposed that the collagen-like domain of the full-length adiponectin is responsible to the dimer dissociation. There are strong evidences that dimerization of the AdipoR1 receptor has a role during the biosynthesis, the trafficking and the signalling of the seven transmembrane receptors.