Linked Life Data

9449632

Source:http://linkedlifedata.com/resource/pubmed/id/9449632

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1998-2-18
pubmed:abstractText
Previous studies have demonstrated that naturally phosphorylated PRL antagonizes the growth-promoting effects of unmodified PRL in two different PRL-responsive cell lines. In this study our aim was to produce a molecular mimic of phosphorylated PRL by substituting a fairly bulky, negatively charged amino acid (glutamate or aspartate) for the normally phosphorylated serine [serine 179 in human PRL (hPRL)]. In addition, because of the marked effect of phosphorylation on biological activity, we investigated the importance of the unmodified serine in the growth-promoting activity of PRL. hPRL complementary DNA was obtained from the American Type Culture Collection and subcloned into pT7-SCII after site-directed mutagenesis using the deoxyuridine approach. Proteins were expressed in Escherichia coli BL21 (DE3) and were primarily found in inclusion bodies. Agonist and antagonist activities of each serine 179 mutant were assessed using the Nb2 bioassay. Compared with standard hPRL, the recombinant wild-type was more active in the Nb2 assay, attesting to both the absence, or low level, of endotoxin contamination in preparations from these cells and the appropriate folding of the molecule. The aspartate and glutamate mutants had no intrinsic agonist activity, but both antagonized the growth-promoting activity of wild-type PRL, with the aspartate mutant proving to be a very effective antagonist. Two hundred picograms per ml of the aspartate mutant negated 75% of the growth response to 400 pg/ml wild-type PRL. When serine 179 was mutated to alanine or valine, mutant PRLs with 0% and 14% of the biological activity of wild-type PRL, respectively, were produced. These results demonstrate 1) that molecular mimicry of the phosphorylated hormone does produce a PRL antagonist, and 2) that the serine at position 179 is crucial to the growth-promoting activity of PRL. The aspartate mutant can now be used to study many aspects of the physiology of PRL.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
139
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
609-16
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Development of recombinant human prolactin receptor antagonists by molecular mimicry of the phosphorylated hormone.
pubmed:affiliation
Division of Biomedical Sciences, University of California, Riverside 92521-0121, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't