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Lundell, Ingrid
Publications (3 of 3) Show all publications
Xu, B., Fällmar, H., Boukharta, L., Pruner, J., Lundell, I., Mohell, N., . . . Larhammar, D. (2013). Mutagenesis and Computational Modeling of Human G‑Protein-Coupled Receptor Y2 for Neuropeptide Y and Peptide YY. Biochemistry, 52(45), 7987-7998
Open this publication in new window or tab >>Mutagenesis and Computational Modeling of Human G‑Protein-Coupled Receptor Y2 for Neuropeptide Y and Peptide YY
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2013 (English)In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 52, no 45, p. 7987-7998Article in journal (Refereed) Published
Abstract [en]

Neuropeptide Y and peptide YY receptor type 2 (Y2) is involved in appetite regulation and several other physiological processes. We have investigated the structure of the human Y2 receptor. Computational modeling of receptor–agonist interactions was used as a guide to design a series of receptor mutants, followed by binding assays using full-length and truncated peptide agonists and the Y2-specific antagonist BIIE0246. Our model suggested a hydrogen bond network among highly conserved residues Thr2.61, Gln3.32, and His7.39, which could play roles in ligand binding and/or receptor structure. In addition, the C-terminus of the peptide could make contact with residues Tyr5.38 and Leu6.51. Mutagenesis of all these positions, followed by binding assays, provides experimental support for our computational model: most of the mutants for the residues forming the proposed hydrogen bond network displayed reduced peptide agonist affinities as well as reduced hPYY3-36 potency in a functional assay. The Ala and Leu mutants of Gln3.32 and His7.39 disrupted membrane expression of the receptor. Combined with the modeling, the experimental results support roles for these hydrogen bond network residues in peptide binding as well as receptor architecture. The reduced agonist affinity for mutants of Tyr5.38 and Leu6.51 supports their role in a binding pocket surrounding the invariant tyrosine at position 36 of the peptide ligands. The results for antagonist BIIE0246 suggest several differences in interactions compared to those of the peptides. Our results lead to a new structural model for NPY family receptors and peptide binding.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2013
National Category
Natural Sciences Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-154994 (URN)10.1021/bi400830c (DOI)000330017700012 ()
Available from: 2011-08-04 Created: 2011-06-14 Last updated: 2019-01-03Bibliographically approved
Sundström, G., Xu, B., Larsson, T. A., Heldin, J., Bergqvist, C. A., Fredriksson, R., . . . Larhammar, D. (2012). Characterization of the neuropeptide Y system in the frog Silurana tropicalis (Pipidae): three peptides and six receptor subtypes. General and Comparative Endocrinology, 177(3), 322-331
Open this publication in new window or tab >>Characterization of the neuropeptide Y system in the frog Silurana tropicalis (Pipidae): three peptides and six receptor subtypes
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2012 (English)In: General and Comparative Endocrinology, ISSN 0016-6480, E-ISSN 1095-6840, Vol. 177, no 3, p. 322-331Article in journal (Refereed) Published
Abstract [en]

Neuropeptide Y and its related peptides PYY and PP (pancreatic polypeptide) are involved in feeding behavior, regulation of the pituitary and the gastrointestinal tract, and numerous other functions. The peptides act on a family of G-protein coupled receptors with 4-7 members in jawed vertebrates. We describe here the NPY system of the Western clawed frog Silurana (Xenopus) tropicalis. Three peptides, NPY, PYY and PP, were identified together with six receptors, namely subtypes Y1, Y2, Y4, Y5, Y7 and Y8. Thus, this frog has all but one of the ancestral seven gnathostome NPY-family receptors, in contrast to mammals which have lost 2-3 of the receptors. Expression levels of mRNA for the peptide and receptor genes were analyzed in a panel of 19 frog tissues using reverse transcriptase quantitative PCR. The peptide mRNAs had broad distribution with highest expression in skin, blood and small intestine. NPY mRNA was present in the three brain regions investigated, but PYY and PP mRNAs were not detectable in any of these. All receptor mRNAs had similar expression profiles with high expression in skin, blood, muscle and heart. Three of the receptors, Y5, Y7 and Y8, could be functionally expressed in HEK-293 cells and characterized with binding studies using the three frog peptides. PYY had the highest affinity for all three receptors (K(i) 0.042-0.34 nM). Also NPY and PP bound to the Y8 receptor with high affinity (0.14 and 0.50 nM). The low affinity of NPY for the Y5 receptor (100-fold lower than PYY) differs from mammals and chicken. This may suggest a less important role of NPY on Y5 in appetite stimulation in the frog compared with amniotes. In conclusion, our characterization of the NPY system in S. tropicalis with its six receptors demonstrates not only greater complexity than in mammals but also some interesting differences in ligand-receptor preferences.

Keywords
NPY, PYY, G-protein-coupled receptor, Silurana tropicalis, evolution
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-129517 (URN)10.1016/j.ygcen.2012.04.027 (DOI)000306390100005 ()22565163 (PubMedID)
Note

Erratum in General and Comparative Endocrinology 2015:215, doi:10.1016/j.ygcen.2014.11.014.

Available from: 2010-08-18 Created: 2010-08-18 Last updated: 2019-01-03Bibliographically approved
Fällmar, H., Sundström, G., Lundell, I., Mohell, N. & Larhammar, D. (2011). Neuropeptide Y/peptide YY receptor Y2 duplicate in zebrafish with unique introns displays distinct peptide binding properties. Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology, 160(4), 166-173
Open this publication in new window or tab >>Neuropeptide Y/peptide YY receptor Y2 duplicate in zebrafish with unique introns displays distinct peptide binding properties
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2011 (English)In: Comparative Biochemistry and Physiology - Part B: Biochemistry & Molecular Biology, ISSN 1096-4959, E-ISSN 1879-1107, Vol. 160, no 4, p. 166-173Article in journal (Other academic) Published
Abstract [en]

The neuropeptide Y-family peptides and receptors are involved in a broad range of functions including appetite regulation. Both the peptide genes and the receptor genes are known to have duplicated in early vertebrate evolution. The ancestral jawed vertebrate had 7 NPY receptors but the number varies between 4 and 7 in extant vertebrates. Herein we describe the identification of an additional NPY receptor in two fish species, zebrafish and medaka. They cluster together with the Y2 receptors in phylogenetic analyses and seem to be orthologous to each other that is why we have named them Y2-2. Their genes differ from Y2 in having introns in the coding region. Binding studies with zebrafish Y2-2 receptors show that the three endogenous peptides NPY, PYYa and PYYb have similar affinities, 0.15-0.66nM. This is in contrast to the Y2 receptor where they differed considerably from one another. N-terminally truncated NPY binds poorly and the Y2 antagonist BIIE0246 binds well to Y2-2, results that are reversed in comparison to Y2. Zebrafish Y2-2 mRNA was detected by PCR in the intestine and the eye, but not in the brain. In conclusion, we have found a novel Y2-like NPY/PYY receptor that probably arose in early teleost fish evolution.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-154990 (URN)10.1016/j.cbpb.2011.08.001 (DOI)000296679800004 ()21855645 (PubMedID)
Available from: 2011-08-04 Created: 2011-06-14 Last updated: 2019-01-03Bibliographically approved
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