Sandbox Reserved 1100: Difference between revisions
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In the middle of the seven transmembrane helices there is a large internal cavity where a <scene name='82/829353/Zinc-binding_site/2'>zinc-binding site</scene> 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 <scene name='82/829353/Helice5/2'>helix V</scene> and <scene name='82/829353/Helix6/2'>VI</scene>, and between the <scene name='82/829353/Helix4/2'>helice IV</scene> and <scene name='82/829353/Helix6/2'>VI</scene>. It has been assumed that these openings are involved in the entrance and exit of both substrate and product. | In the middle of the seven transmembrane helices there is a large internal cavity where a <scene name='82/829353/Zinc-binding_site/2'>zinc-binding site</scene> 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 <scene name='82/829353/Helice5/2'>helix V</scene> and <scene name='82/829353/Helix6/2'>VI</scene>, and between the <scene name='82/829353/Helix4/2'>helice IV</scene> and <scene name='82/829353/Helix6/2'>VI</scene>. 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 <scene name='82/829353/H191/2'>H191</scene> in the helix II, <scene name='82/829353/H337/2'>H337</scene> and <scene name='82/829353/H341/2'>H341</scene> in the <scene name='82/829353/Helix7/2'>helix VII</scene>. 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 <scene name='82/829353/Helix2/2'>helix II</scene>, <scene name='82/829353/Helix3/2'>III</scene> and <scene name='82/829353/Helix7/2'>VII</scene> 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. <ref name="doc1"/> | In this cavity, there is a zinc ion which is coordinated thanks to three histidine residues. These three histidine residues are <scene name='82/829353/H191/2'>H191</scene> in the helix II, <scene name='82/829353/H337/2'>H337</scene> and <scene name='82/829353/H341/2'>H341</scene> in the <scene name='82/829353/Helix7/2'>helix VII</scene>. 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 <scene name='82/829353/Helix2/2'>helix II</scene>, <scene name='82/829353/Helix3/2'>III</scene> and <scene name='82/829353/Helix7/2'>VII</scene> 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. <ref name="doc1"/> | ||
AdipoR1 has the capacity to form oligomers. <ref name="doc3"> Takashi Kadowaki and Toshimasa Yamauchi et al. « Adiponectin and adiponectin receptors». https://www.ncbi.nlm.nih.gov/pubmed/15897298</ref | AdipoR1 has the capacity to form oligomers. <ref name="doc3"> Takashi Kadowaki and Toshimasa Yamauchi et al. « Adiponectin and adiponectin receptors». https://www.ncbi.nlm.nih.gov/pubmed/15897298</ref> 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 <scene name='82/829353/Helice5/2'>helix V</scene>. 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. <ref name="doc4"> Kosel D, Heiker JT, Juhl C, Wottawah CM, Blüher M, Mörl K, Beck-Sickinger AG et al. « Dimerization of adiponectin 1 is inhibited by adiponectin » Journal of Cell Science 123, 1320-1328 : https://www.ncbi.nlm.nih.gov/pubmed/20332107</ref> | ||
