Linked Life Data

15557207

Source:http://linkedlifedata.com/resource/pubmed/id/15557207

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2005-2-18
pubmed:abstractText
The human equilibrative nucleoside transporter 1 (hENT1) is an important modulator of the physiological action of adenosine. We identified amino acid residues involved in adenosine transport using a yeast-based assay to rapidly screen and identify randomly generated hENT1 mutants that exhibited decreased sensitivity to inhibition of adenosine transport by various hENT1 competitive inhibitors. We identified Met89 and Ser160 as important in the affinity of hENT1 for various substrates and inhibitors. Mutation to Met89Cys or Ser160Cys significantly (p < 0.05) increased the S6-(4-nitrobenzyl)-mercaptopurine riboside (NBMPR) IC50 values by approximately 4- and 6-fold, respectively (42 +/- 13 and 65 +/- 1.6 nM) compared with the wild-type transporter (11 +/- 0.7 nM). The double mutant Met89Cys/Ser160Cys synergistically increased the NBMPR IC50 value to approximately 19-fold of that of the wild-type transporter. In contrast, compared with wild-type hENT1, the sensitivity to dipyridamole inhibition was significantly (p < 0.05) increased by only the Ser160Cys (approximately 2.6-fold) or the double mutant Met89Cys/Ser160Cys (approximately 4.7-fold) but not by the Met89Cys mutant. Mutation to Met89Cys or Ser160Cys increased the Km of adenosine (approximately 8- and 3-fold) and the Ki of guanosine (approximately 6- and 2-fold). The double mutant increased both the Km value of adenosine and the Ki value of guanosine by approximately 8-fold and seemed to confer no additional reduction in adenosine or guanosine affinity than that by mutation of Met89 alone. Together, these data indicate that transmembrane domains (TMDs) 2 (Met89) and 4 (Ser160) of hENT1 interact and are important in conferring sensitivity to NBMPR. In contrast, Ser160 and Met89 of hENT1, respectively, play a dominant role in conferring sensitivity to dipyridamole and adenosine/guanosine affinity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0026-895X
pubmed:author
pubmed:issnType
Print
pubmed:volume
67
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
837-44
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:15557207-Adenosine, pubmed-meshheading:15557207-Amino Acid Sequence, pubmed-meshheading:15557207-Biological Transport, pubmed-meshheading:15557207-Dipyridamole, pubmed-meshheading:15557207-Equilibrative Nucleoside Transporter 1, pubmed-meshheading:15557207-Genetic Complementation Test, pubmed-meshheading:15557207-Guanosine, pubmed-meshheading:15557207-Humans, pubmed-meshheading:15557207-Kinetics, pubmed-meshheading:15557207-Methionine, pubmed-meshheading:15557207-Molecular Sequence Data, pubmed-meshheading:15557207-Mutagenesis, Site-Directed, pubmed-meshheading:15557207-Point Mutation, pubmed-meshheading:15557207-Recombinant Proteins, pubmed-meshheading:15557207-Sequence Alignment, pubmed-meshheading:15557207-Sequence Homology, Amino Acid, pubmed-meshheading:15557207-Serine, pubmed-meshheading:15557207-Thioinosine
pubmed:year
2005
pubmed:articleTitle
Residues Met89 and Ser160 in the human equilibrative nucleoside transporter 1 affect its affinity for adenosine, guanosine, S6-(4-nitrobenzyl)-mercaptopurine riboside, and dipyridamole.
pubmed:affiliation
Department of Pharmaceutics, Box 357610, University of Washington, Seattle, WA 98195, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.