By interacting with the C-terminal Phe of apelin, Phe255 and Trp259 in helix VI of the apelin receptor are critical for internalization.

Abstract : Apelin is the endogenous ligand of the orphan seven-transmembrane domain (TM) G protein-coupled receptor APJ. Apelin is involved in the regulation of body fluid homeostasis and cardiovascular functions. We previously showed the importance of the C-terminal Phe of apelin 17 (K17F) in the hypotensive activity of this peptide. Here, we show either by deleting the Phe residue (K16P) or by substituting it by an Ala (K17A), that it plays a crucial role in apelin receptor internalization but not in apelin binding or in Gαi-protein coupling. Then we built a homology three-dimensional model of the human apelin receptor using the cholecystokinin receptor-1 model as a template, and we subsequently docked K17F into the binding site. We visualized a hydrophobic cavity at the bottom of the binding pocket in which the C-terminal Phe of K17F was embedded by Trp152 in TMIV and Trp259 and Phe255 in TMVI. Using molecular modeling and site-directed mutagenesis studies, we further showed that Phe255 and Trp259 are key residues in triggering receptor internalization without playing a role in apelin binding or in Gαi-protein coupling. These findings bring new insights into apelin receptor activation and show that Phe255 and Trp259, by interacting with the C-terminal Phe of the pyroglutamyl form of apelin 13 (pE13F) or K17F, are crucial for apelin receptor internalization.
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https://hal.archives-ouvertes.fr/hal-00547969
Contributor : Bernard Maigret <>
Submitted on : Saturday, December 18, 2010 - 1:31:13 AM
Last modification on : Thursday, April 11, 2019 - 4:02:50 PM

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  • HAL Id : hal-00547969, version 1
  • PUBMED : 20675385

Citation

Xavier Iturrioz, Romain Gerbier, Vincent Leroux, Rodrigo Alvear-Perez, Bernard Maigret, et al.. By interacting with the C-terminal Phe of apelin, Phe255 and Trp259 in helix VI of the apelin receptor are critical for internalization.. Journal of Biological Chemistry, American Society for Biochemistry and Molecular Biology, 2010, 285 (42), pp.32627-32637. ⟨hal-00547969⟩

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