Linked Life Data

12381737

Source:http://linkedlifedata.com/resource/pubmed/id/12381737

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
50
pubmed:dateCreated
2002-12-9
pubmed:abstractText
Accumulating evidence suggests that receptor protein-tyrosine kinases, like the platelet-derived growth factor receptor-beta (PDGFRbeta) and epidermal growth factor receptor (EGFR), may be desensitized by serine/threonine kinases. One such kinase, G protein-coupled receptor kinase-2 (GRK2), is known to mediate agonist-dependent phosphorylation and desensitization of multiple heptahelical receptors. In testing whether GRK2 could phosphorylate and desensitize the PDGFRbeta, we first found by phosphoamino acid analysis that cells expressing GRK2 could serine-phosphorylate the PDGFRbeta in an agonist-dependent manner. Augmentation or inhibition of GRK2 activity in cells, respectively, reduced or enhanced tyrosine phosphorylation of the PDGFRbeta but not the EGFR. Either overexpressed in cells or as a purified protein, GRK2 demonstrated agonist-promoted serine phosphorylation of the PDGFRbeta and, unexpectedly, the EGFR as well. Because GRK2 did not phosphorylate a kinase-dead (K634R) PDGFRbeta mutant, GRK2-mediated PDGFRbeta phosphorylation required receptor tyrosine kinase activity, as does PDGFRbeta ubiquitination. Agonist-induced ubiquitination of the PDGFRbeta, but not the EGFR, was enhanced in cells overexpressing GRK2. Nevertheless, GRK2 overexpression did not augment PDGFRbeta down-regulation. Like the vast majority of GRK2 substrates, the PDGFRbeta, but not the EGFR, activated heterotrimeric G proteins allosterically in membranes from cells expressing physiologic protein levels. We conclude that GRK2 can phosphorylate and desensitize the PDGFRbeta, perhaps through mechanisms related to receptor ubiquitination. Specificity of GRK2 for receptor protein-tyrosine kinases, expressed at physiologic levels, may be determined by the ability of these receptors to activate heterotrimeric G proteins, among other factors.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
48261-9
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Phosphorylation of the platelet-derived growth factor receptor-beta and epidermal growth factor receptor by G protein-coupled receptor kinase-2. Mechanisms for selectivity of desensitization.
pubmed:affiliation
Department of Medicine (Cardiology), Duke University Medical Center, Durham, North Carolina 27710, USA. neil.freedman@duke.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't