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Essential role of TM V and VI for binding the C-terminal sequences of Des-Arg-kinins

Item Type:Article
Title:Essential role of TM V and VI for binding the C-terminal sequences of Des-Arg-kinins
Creators Name:Santos, E.L. and de Picoli Souza, K. and Cibrian-Uhalte, E. and Oliveira, S.M. and Bader, M. and Costa-Neto, C.M. and Oliveira, L. and Pesquero, J.B.
Abstract:In the kallikrein-kinin and renin-angiotensin systems the main receptors, B(1) and B(2) (kinin receptors) and AT(1) and AT(2) (angiotensin receptors) respectively, are seven-transmembrane domain G-protein-coupled receptors. Considering that the B(1) agonists Des-Arg(9)-BK (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe), Lys-desArg(9)-BK or Des-Arg(10)-KD (Lys-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe) and the AT(1) agonist (Asp-Arg-Val-Tyr-Ile-His-Pro-Phe) have the same two residues at the C-terminal region (i.e. Pro-Phe), we hypothesized that TM V and TM VI of the B(1) receptor could play an essential role in agonist binding and activity, being these regions receptor sites for binding the C-terminal sequences of Des-Arg-kinins similarly to that observed to AT(1) receptor. To investigate this hypothesis, we replaced Arg(212) for Ala at the top of the TM V and the sequence 274-282 (CPYHFFAFL) in TM VI of the rat kinin B(1) receptor by the B(2) receptor homologous sequence, 289-297 (FPFQISTFL) and subsequently analyzed the consequences of these mutations by competition binding and functional assays. Despite correct expression, observed at the mRNA and protein level by RT-PCR and confocal microscopy, respectively, no agonist binding and function was verified for the mutated receptors. Therefore, our results suggest an important role for Arg(212) in the TM V and a region of TM VI of rat B(1) receptor in the interaction with the C-terminal residues of Des-Arg-kinins, similar to that observed with AngII.
Keywords:Mutagenesis, Kinin B1 receptor, G-protein-coupled receptors, Des-Arg-kinins
Source:International Immunopharmacology
Page Range:282-288
Date:February 2008
Official Publication:https://doi.org/10.1016/j.intimp.2007.09.007
PubMed:View item in PubMed

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