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A proposed bovine neuropeptide Y (NPY) receptor cDNA clone, or its human homologue, confers neither NPY binding sites nor NPY responsiveness on transfected cells.
Jazin, E E; Yoo, H; Blomqvist, A G; Yee, F; Weng, G; Walker, M W; Salon, J; Larhammar, D; Wahlestedt, C.
Afiliação
  • Jazin EE; Department of Medical Genetics, Uppsala University, Sweden.
Regul Pept ; 47(3): 247-58, 1993 Sep 22.
Article em En | MEDLINE | ID: mdl-8234909
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.
Assuntos
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Base de dados: MEDLINE Assunto principal: Neuropeptídeo Y / Receptores de Neuropeptídeo Y / DNA Complementar Limite: Animals / Humans Idioma: En Ano de publicação: 1993 Tipo de documento: Article
Buscar no Google
Base de dados: MEDLINE Assunto principal: Neuropeptídeo Y / Receptores de Neuropeptídeo Y / DNA Complementar Limite: Animals / Humans Idioma: En Ano de publicação: 1993 Tipo de documento: Article