A proposed bovine neuropeptide Y (NPY) receptor cDNA clone, or its human homologue, confers neither NPY binding sites nor NPY responsiveness on transfected cells
| Autor: | Gezhi Weng, Heahyun Yoo, Anders G. Blomqvist, Frances Yee, John Salon, Claes Wahlestedt, Dan Larhammar, Elena Jazin, Mary W. Walker |
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| Rok vydání: | 1993 |
| Předmět: |
DNA
Complementary Physiology Molecular Sequence Data Clinical Biochemistry Biology Transfection Polymerase Chain Reaction Biochemistry Cell Line Cellular and Molecular Neuroscience Endocrinology Sequence Homology Nucleic Acid Cyclic AMP Animals Humans Neuropeptide Y Amino Acid Sequence Cloning Molecular Binding site Receptor Peptide sequence chemistry.chemical_classification Binding Sites Base Sequence Neuropeptide Y receptor Molecular biology Angiotensin II humanities Receptors Neuropeptide Y Amino acid Transmembrane domain chemistry Cattle Heterologous expression Sequence Alignment |
| Zdroj: | Regulatory Peptides. 47:247-258 |
| ISSN: | 0167-0115 |
| Popis: | Receptors with seven transmembrane domains (7TM) constitute a large family of structurally and functionally related proteins which respond to various types of ligands. We describe here the cloning and expression of a human 7TM receptor, denoted hFB22 (human Fetal Brain 22), which is the homologue (92% amino acid identity) of a bovine receptor (LCR1) reported by others to bind neuropeptide Y (NPY) with a pharmacological profile of the Y3 receptor subtype. However, upon expression in COS1 (confirmed by Northern analysis), COS7 or CHO-K1 cells, the hFB22 receptor did not confer specific 125I-Bolton-Hunter-NPY, 3H-propionyl-NPY or 125I-peptide YY (PYY) binding sites, in either intact cells or in membrane preparations. Similarly, cells transfected with the corresponding bovine clone (LCR1) did not show specific NPY/PYY binding exceeding that resulting from endogenous binding sites; mock-transfected COS7 cells, used frequently for heterologous expression of receptors, were found to have endogenous specific 125I-NPY binding sites (Bmax = 112 fmol/mg protein; Kd = 0.25 nM). Moreover, the hFB22 transfected cells, when compared to control transfected cells, did not display de novo NPY- or PYY-induced second messenger responses, i.e., (1) inhibition of forskolin-stimulated cAMP accumulation or (2) 45Ca2+ influx. The presence of hFB22 mRNA was detected in several human neuroblastoma cell lines, none of which was found to express Y3-like NPY binding sites. hFB22 displays 39% amino acid sequence identity (in the transmembrane regions) to the human interleukin-8 receptor, and 32-36% amino acid identity to the human receptors of angiotensin II, bradykinin, and n-formylpeptide, but only 23% amino acid identity to the previously described human NPY/PYY receptor of the Y1 receptor subtype. Our results show that hFB22 and LCR1 do not encode NPY receptors, and their true ligand(s) remains to be identified. |
| Databáze: | OpenAIRE |
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