Sequence and expression pattern of a novel human orphan G-protein-coupled receptor, GPRC5B, a family C receptor with a short amino-terminal domain.
Query of GenBank with the amino acid sequence of human metabotropic glutamate receptor subtype 2 (mGluR2) identified a predicted gene product of unknown function on BAC clone CIT987SK-A-69G12 (located on chromosome band 16p12) as a homologous protein. The transcript, entitled GPRC5B, was cloned from an expressed sequence tag clone that contained the entire open reading frame of the transcript encoding a protein of 395 amino acids. Analysis of the protein sequence reveal that GPRC5B contains a signal peptide and seven transmembrane alpha-helices, which is a hallmark of G-protein-coupled receptors (GPCRs). GPRC5B displays homology to retinoic acid-inducible gene 1 (RAIG1, 33% sequence identity) and to several family C (mGluR-like) GPCRs (20-25% sequence identity). Both RAIG1 and GPRC5B have short extracellular amino-terminal domains (ATDs) that contrast the very long ATDs characterizing the receptors currently assigned to family C. However, our results strongly indicate that RAIG1 and GPRC5B form a new subgroup of family C characterized by short ATDs. GPRC5B mRNA is widely expressed in peripheral and central tissues with highest abundance in kidney, pancreas, and testis. This mRNA expression pattern is markedly different from that of RAIG1, which shows a slightly more restricted expression pattern with highest abundance in lung tissue.
Bräuner-Osborne
H
H
NeuroScience PharmaBiotec Research Centre, Department of Medical Chemistry, The Royal Danish School of Pharmacy, 2 Universitetsparken, Copenhagen, DK-2100, Denmark. hbo@dfh.dk
Krogsgaard-Larsen
P
P
D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D002885:Chromosomes, Human, Pair 16; D003001:Cloning, Molecular; D005091:Exons; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015723:Gene Library; D006801:Humans; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000737:chemistry; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled; D017470:Receptors, Glutamate / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
C116760:GPRC5A protein, human; C410799:GPRC5B protein, human; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D017470:Receptors, Glutamate; D019204:GTP-Binding Proteins