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GPR99, a new G protein-coupled receptor with homology to a new subgroup of nucleotide receptors.

Wittenberger T, Hellebrand S, Munck A, Kreienkamp HJ, Schaller HC, Hampe W - BMC Genomics (2002)

Bottom Line: The mRNA of GPR99 was found in kidney and placenta.We identified a new orphan receptor, GPR99, with homology to the family of G protein-coupled nucleotide receptors.Phylogenetic analysis separates this family into different subgroups predicting a nucleotide ligand for GPR99.

View Article: PubMed Central - HTML - PubMed

Affiliation: Zentrum für Molekulare Neurobiologie, Universität Hamburg, Martinistr, 52, D-20246 Hamburg, Germany. timo.wittenberger@altanapharma.com

ABSTRACT

Background: Based on sequence similarity, the superfamily of G protein-coupled receptors (GPRs) can be subdivided into several subfamilies, the members of which often share similar ligands. The sequence data provided by the human genome project allows us to identify new GPRs by in silico homology screening, and to predict their ligands.

Results: By searching the human genomic database with known nucleotide receptors we discovered the gene for GPR99, a new orphan GPR. The mRNA of GPR99 was found in kidney and placenta. Phylogenetic analysis groups GPR99 into the P2Y subfamily of GPRs. Based on the phylogenetic tree we propose a new classification of P2Y nucleotide receptors into two subgroups predicting a nucleotide ligand for GPR99. By assaying known nucleotide ligands on heterologously expressed GPR99, we could not identify specifically activating substances, indicating that either they are not agonists of GPR99 or that GPR99 was not expressed at the cell surface. Analysis of the chromosomal localization of all genes of the P2Y subfamily revealed that all members of subgroup "a" are encoded by less than 370 kb on chromosome 3q24, and that the genes of subgroup "b" are clustered on one hand to chromosome 11q13.5 and on the other on chromosome 3q24-25.1 close to the subgroup "a" position. Therefore, the P2Y subfamily is a striking example for local gene amplification.

Conclusions: We identified a new orphan receptor, GPR99, with homology to the family of G protein-coupled nucleotide receptors. Phylogenetic analysis separates this family into different subgroups predicting a nucleotide ligand for GPR99.

No MeSH data available.


Phylogenetic analysis of human nucleotide GPRs. (A) Phylogenetic tree. The two nucleotide-receptor subgroups "a" and "b" and the related non-nucleotide receptors (n) are indicated. Chromosomal localizations and known endogenous ligands with highest affinities (in brackets) are indicated for each GPR. Phylogenetic analysis assigned a support value of at least 53% to each internal branch. (B) Alignment of putative nucleotide-binding motifs at the beginning of transmembrane domain seven. The proline-containing motif towards the end of transmembrane domain seven is indicated below the alignment. The accession numbers of the receptors are: GPR86, AAK01864; GPR87, AAK01858; GPR91, AF348078; H963, AAC51846; KIAA0001, BAA02791; P2Y1, CAA07339; P2Y2, XP_006367; P2Y4, P51582; P2Y5, P43657; P2Y6, Q15077; P2Y7, Q15722; P2Y9, Q99677; P2Y10, AAB57836; P2Y11, AAB88674; P2Y12, AAG48944. (C) Schematic diagram of the subgroup "a" gene cluster on chromosome 3q24. In the upper part the overlapping BAC clones, coding for the receptors indicated below, are given. The genes of P2Y12, GPR86, and GPR87 are located in a head-to-tail configuration within a distance of 46.5 kb on one contig of AC024886. The GPR87 gene is also present on AC078816, which overlaps with AC024886 in 15 kb of its sequence. The H963 gene is encoded by AC078816 and AC011103, the KIAA0001 gene by AC078816, AC011103, and AC063935. From these data the order of the genes can be deduced. Gaps in the known sequence of the BAC clones coding for H963 and KIA0001 make it impossible to determine the orientation and exact size of the intergenic regions.
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Figure 3: Phylogenetic analysis of human nucleotide GPRs. (A) Phylogenetic tree. The two nucleotide-receptor subgroups "a" and "b" and the related non-nucleotide receptors (n) are indicated. Chromosomal localizations and known endogenous ligands with highest affinities (in brackets) are indicated for each GPR. Phylogenetic analysis assigned a support value of at least 53% to each internal branch. (B) Alignment of putative nucleotide-binding motifs at the beginning of transmembrane domain seven. The proline-containing motif towards the end of transmembrane domain seven is indicated below the alignment. The accession numbers of the receptors are: GPR86, AAK01864; GPR87, AAK01858; GPR91, AF348078; H963, AAC51846; KIAA0001, BAA02791; P2Y1, CAA07339; P2Y2, XP_006367; P2Y4, P51582; P2Y5, P43657; P2Y6, Q15077; P2Y7, Q15722; P2Y9, Q99677; P2Y10, AAB57836; P2Y11, AAB88674; P2Y12, AAG48944. (C) Schematic diagram of the subgroup "a" gene cluster on chromosome 3q24. In the upper part the overlapping BAC clones, coding for the receptors indicated below, are given. The genes of P2Y12, GPR86, and GPR87 are located in a head-to-tail configuration within a distance of 46.5 kb on one contig of AC024886. The GPR87 gene is also present on AC078816, which overlaps with AC024886 in 15 kb of its sequence. The H963 gene is encoded by AC078816 and AC011103, the KIAA0001 gene by AC078816, AC011103, and AC063935. From these data the order of the genes can be deduced. Gaps in the known sequence of the BAC clones coding for H963 and KIA0001 make it impossible to determine the orientation and exact size of the intergenic regions.

Mentions: Phylogenetic analysis of all human members of the P2Y subfamily of GPRs results in three subgroups designated "a", "b", and "n" (Fig. 3A). Subgroup "n" (for non-nucleotide receptors) contains P2Y5, P2Y7, P2Y9, and P2Y10, all of which, for homology reasons, were designated P2Y receptors. Closer analysis revealed that none of these is activated by nucleotides, but one of them, P2Y7, binds leukotriene B4 [5]. In contrast, GPR99 belongs to subgroup "b" which, in addition to the new orphan receptor GPR91, consists of five receptors with proven nucleotide agonists, hinting at a similar ligand for GPR91 and GPR99. Subgroup "a" consists of the orphan receptors GPR87 and H963, and of GPR86/P2Y13[6], P2Y12 and KIAA0001, which bind the nucleotide ligands ADP, ADP, and UDP-glucose, respectively.


GPR99, a new G protein-coupled receptor with homology to a new subgroup of nucleotide receptors.

Wittenberger T, Hellebrand S, Munck A, Kreienkamp HJ, Schaller HC, Hampe W - BMC Genomics (2002)

Phylogenetic analysis of human nucleotide GPRs. (A) Phylogenetic tree. The two nucleotide-receptor subgroups "a" and "b" and the related non-nucleotide receptors (n) are indicated. Chromosomal localizations and known endogenous ligands with highest affinities (in brackets) are indicated for each GPR. Phylogenetic analysis assigned a support value of at least 53% to each internal branch. (B) Alignment of putative nucleotide-binding motifs at the beginning of transmembrane domain seven. The proline-containing motif towards the end of transmembrane domain seven is indicated below the alignment. The accession numbers of the receptors are: GPR86, AAK01864; GPR87, AAK01858; GPR91, AF348078; H963, AAC51846; KIAA0001, BAA02791; P2Y1, CAA07339; P2Y2, XP_006367; P2Y4, P51582; P2Y5, P43657; P2Y6, Q15077; P2Y7, Q15722; P2Y9, Q99677; P2Y10, AAB57836; P2Y11, AAB88674; P2Y12, AAG48944. (C) Schematic diagram of the subgroup "a" gene cluster on chromosome 3q24. In the upper part the overlapping BAC clones, coding for the receptors indicated below, are given. The genes of P2Y12, GPR86, and GPR87 are located in a head-to-tail configuration within a distance of 46.5 kb on one contig of AC024886. The GPR87 gene is also present on AC078816, which overlaps with AC024886 in 15 kb of its sequence. The H963 gene is encoded by AC078816 and AC011103, the KIAA0001 gene by AC078816, AC011103, and AC063935. From these data the order of the genes can be deduced. Gaps in the known sequence of the BAC clones coding for H963 and KIA0001 make it impossible to determine the orientation and exact size of the intergenic regions.
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Figure 3: Phylogenetic analysis of human nucleotide GPRs. (A) Phylogenetic tree. The two nucleotide-receptor subgroups "a" and "b" and the related non-nucleotide receptors (n) are indicated. Chromosomal localizations and known endogenous ligands with highest affinities (in brackets) are indicated for each GPR. Phylogenetic analysis assigned a support value of at least 53% to each internal branch. (B) Alignment of putative nucleotide-binding motifs at the beginning of transmembrane domain seven. The proline-containing motif towards the end of transmembrane domain seven is indicated below the alignment. The accession numbers of the receptors are: GPR86, AAK01864; GPR87, AAK01858; GPR91, AF348078; H963, AAC51846; KIAA0001, BAA02791; P2Y1, CAA07339; P2Y2, XP_006367; P2Y4, P51582; P2Y5, P43657; P2Y6, Q15077; P2Y7, Q15722; P2Y9, Q99677; P2Y10, AAB57836; P2Y11, AAB88674; P2Y12, AAG48944. (C) Schematic diagram of the subgroup "a" gene cluster on chromosome 3q24. In the upper part the overlapping BAC clones, coding for the receptors indicated below, are given. The genes of P2Y12, GPR86, and GPR87 are located in a head-to-tail configuration within a distance of 46.5 kb on one contig of AC024886. The GPR87 gene is also present on AC078816, which overlaps with AC024886 in 15 kb of its sequence. The H963 gene is encoded by AC078816 and AC011103, the KIAA0001 gene by AC078816, AC011103, and AC063935. From these data the order of the genes can be deduced. Gaps in the known sequence of the BAC clones coding for H963 and KIA0001 make it impossible to determine the orientation and exact size of the intergenic regions.
Mentions: Phylogenetic analysis of all human members of the P2Y subfamily of GPRs results in three subgroups designated "a", "b", and "n" (Fig. 3A). Subgroup "n" (for non-nucleotide receptors) contains P2Y5, P2Y7, P2Y9, and P2Y10, all of which, for homology reasons, were designated P2Y receptors. Closer analysis revealed that none of these is activated by nucleotides, but one of them, P2Y7, binds leukotriene B4 [5]. In contrast, GPR99 belongs to subgroup "b" which, in addition to the new orphan receptor GPR91, consists of five receptors with proven nucleotide agonists, hinting at a similar ligand for GPR91 and GPR99. Subgroup "a" consists of the orphan receptors GPR87 and H963, and of GPR86/P2Y13[6], P2Y12 and KIAA0001, which bind the nucleotide ligands ADP, ADP, and UDP-glucose, respectively.

Bottom Line: The mRNA of GPR99 was found in kidney and placenta.We identified a new orphan receptor, GPR99, with homology to the family of G protein-coupled nucleotide receptors.Phylogenetic analysis separates this family into different subgroups predicting a nucleotide ligand for GPR99.

View Article: PubMed Central - HTML - PubMed

Affiliation: Zentrum für Molekulare Neurobiologie, Universität Hamburg, Martinistr, 52, D-20246 Hamburg, Germany. timo.wittenberger@altanapharma.com

ABSTRACT

Background: Based on sequence similarity, the superfamily of G protein-coupled receptors (GPRs) can be subdivided into several subfamilies, the members of which often share similar ligands. The sequence data provided by the human genome project allows us to identify new GPRs by in silico homology screening, and to predict their ligands.

Results: By searching the human genomic database with known nucleotide receptors we discovered the gene for GPR99, a new orphan GPR. The mRNA of GPR99 was found in kidney and placenta. Phylogenetic analysis groups GPR99 into the P2Y subfamily of GPRs. Based on the phylogenetic tree we propose a new classification of P2Y nucleotide receptors into two subgroups predicting a nucleotide ligand for GPR99. By assaying known nucleotide ligands on heterologously expressed GPR99, we could not identify specifically activating substances, indicating that either they are not agonists of GPR99 or that GPR99 was not expressed at the cell surface. Analysis of the chromosomal localization of all genes of the P2Y subfamily revealed that all members of subgroup "a" are encoded by less than 370 kb on chromosome 3q24, and that the genes of subgroup "b" are clustered on one hand to chromosome 11q13.5 and on the other on chromosome 3q24-25.1 close to the subgroup "a" position. Therefore, the P2Y subfamily is a striking example for local gene amplification.

Conclusions: We identified a new orphan receptor, GPR99, with homology to the family of G protein-coupled nucleotide receptors. Phylogenetic analysis separates this family into different subgroups predicting a nucleotide ligand for GPR99.

No MeSH data available.