Document Detail


Defects of tyrosine289phenylalanine mutation on binding and functional properties of the human tachykinin NK2 receptor stably expressed in chinese hamster ovary cells.
MedLine Citation:
PMID:  10086323     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A point mutation was made at position 289 in the transmembrane segment 7 of the human tachykinin NK2 receptor to yield a tyrosine/phenylalanine (Tyr/Phe) substitution. Chinese hamster ovary cells stably transfected with the wild-type or Tyr289Phe mutant NK2 receptor both bound neurokinin A (NKA) and the synthetic NK2 receptor-selective agonists, GR 64349 and [betaAla8]NKA(4-10), with high and even affinities. Neurokinin B (NKB) and substance P (SP) also displayed sizeable binding affinities, albeit with lower affinity as compared to NKA. In a functional assay (production of inositol-1,4,5-trisphosphate, IP3), NKA, GR 64349, and [betaAla8]INKA(4-10) stimulated IP3 accumulation via the wild-type and mutant receptors with similar potencies. On the other hand, NKB and SP exhibited a dramatic reduction in their agonist efficacies at the mutant receptor, NKB acting as a partial agonist (maximum effect = 50% of the response to NKA) and SP being totally inactive. The results obtained with phenoxybenzamine inactivation experiments indicated that a large and similar receptor reserve existed for both the wild-type and the mutant receptor. SP, which displayed sizeable binding affinity for the mutant receptor but did not stimulate IP3 accumulation, antagonized the agonist effect of NKA. The antagonist action of SP at the mutant NK2 receptor cannot be ascribed to receptor internalization. The Tyr/Phe replacement at position 289 markedly reduced the binding affinity and antagonist potency of the non-peptide ligand, SR 48968, without affecting the binding affinity and antagonist potency of the bicyclic peptide antagonist MEN 11420. The results indicate that the hydroxyl radical function of Tyr289 in transmembrane segment 7 of the human NK2 receptor is, directly or indirectly, involved in stimulus transduction when the NK2 receptor is occupied by NKB or SP, but not when using NKA or NK2 receptor-selective agonists.
Authors:
A R Renzetti; R M Catalioto; C Carloni; M Criscuoli; P Cucchi; A Giolitti; S Zappitelli; L Rotondaro; C A Maggi
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Biochemical pharmacology     Volume:  57     ISSN:  0006-2952     ISO Abbreviation:  Biochem. Pharmacol.     Publication Date:  1999 Apr 
Date Detail:
Created Date:  1999-04-01     Completed Date:  1999-04-01     Revised Date:  2005-11-17    
Medline Journal Info:
Nlm Unique ID:  0101032     Medline TA:  Biochem Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  899-906     Citation Subset:  IM    
Affiliation:
Department of Pharmacology, Menarini Richerche, Florence, Italy.
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MeSH Terms
Descriptor/Qualifier:
Animals
Binding, Competitive
CHO Cells
Cricetinae
Guanosine Triphosphate / metabolism
Humans
Inositol 1,4,5-Trisphosphate / metabolism
Neurokinin A / antagonists & inhibitors,  metabolism
Phenoxybenzamine / pharmacology
Phenylalanine / genetics,  physiology*
Point Mutation
Receptors, Neurokinin-2 / genetics,  physiology*
Signal Transduction*
Substance P / pharmacology
Tachykinins / metabolism*
Transfection
Tyrosine / genetics,  physiology*
Chemical
Reg. No./Substance:
0/Receptors, Neurokinin-2; 0/Tachykinins; 33507-63-0/Substance P; 55520-40-6/Tyrosine; 59-96-1/Phenoxybenzamine; 63-91-2/Phenylalanine; 85166-31-0/Inositol 1,4,5-Trisphosphate; 86-01-1/Guanosine Triphosphate; 86933-74-6/Neurokinin A

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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