title: Functional expression of a novel human neurokinin-3 receptor homolog that binds [3H]senktide and [125I-MePhe7]neurokinin B, and is responsive to tachykinin peptide agonists.
abstract: In 1992, Xie et al. identified a cDNA sequence in the expression cloning search for the kappa opioid receptor. When the cDNA was expressed in Cos-7 cells, binding of opioid compounds was observed to be of low affinity and without kappa, mu, or delta selectivity [Xie, G.-X., Miyajima, A. and Goldstein, A. (1992) Proc. Natl. Acad. Sci. USA 89, 4124-4128]. This cDNA was highly homologous to the human neurokinin-3 (NK-3) receptor sequence, and displayed lower homology to NK-1 and NK-2 sequences. This sequence was stably expressed in Chinese hamster ovary cells, which do not express neurokinin receptors naturally, and ligand binding and second messenger characteristics were compared with a human NK-3 receptor. The NK-3 receptor homolog bound [3H] senktide with a Kd of 39 nM, similar to that of the NK-3 receptor. The rank order of tachykinin peptides competing for [3H]senktide binding at the NK-3 receptor homolog was [MePhe7]neurokinin B > senktide > substance P = neurokinin A > neurokinin B. This cell line also bound [125I-MePhe7]neurokinin B; however, neurokinin B was an effective competitor. Tachykinin peptides stimulated both inositol phospholipid hydrolysis and arachidonic acid release at NK-3 and NK-3 receptor homolog cell lines, with similar rank orders of potency of [MePhe7] neurokinin B = neurokinin B = senktide > NKA = substance P. These results indicate that expression of the NK-3 receptor homolog cDNA in the Chinese hamster ovary cell system induces the expression of a receptor site with many similarities but certain key differences from that of the human NK-3 receptor. The results are discussed with reference to the existence of a novel human tachykinin receptor.
authors.affiliation: Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA. krausej@thalamus.wustl.edu
authors.forename: J E
authors.initials: JE
authors.lastname: Krause
authors.forename: P T
authors.initials: PT
authors.lastname: Staveteig
authors.forename: J N
authors.initials: JN
authors.lastname: Mentzer
authors.forename: S K
authors.initials: SK
authors.lastname: Schmidt
authors.forename: J B
authors.initials: JB
authors.lastname: Tucker
authors.forename: R M
authors.initials: RM
authors.lastname: Brodbeck
authors.forename: J Y
authors.initials: JY
authors.lastname: Bu
authors.forename: V V
authors.initials: VV
authors.lastname: Karpitskiy
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000032:analysis; D001667:Binding, Competitive; D016466:CHO Cells; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007295:Inositol Phosphates / Q000032:analysis; D015287:Neurokinin B / Q000031:analogs & derivatives* / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism*; D011869:Radioligand Assay; D018042:Receptors, Neurokinin-3 / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015290:Second Messenger Systems; D017385:Sequence Homology; D013373:Substance P / Q000031:analogs & derivatives* / Q000378:metabolism; D015320:Tachykinins / Q000819:agonists*
chemical_list: D007295:Inositol Phosphates; D010446:Peptide Fragments; D018042:Receptors, Neurokinin-3; D011994:Recombinant Proteins; D015320:Tachykinins; C080394:neurokinin B, MePhe(7)-; C054724:senktide; D016718:Arachidonic Acid; D013373:Substance P; D015287:Neurokinin B