Linked Life Data

14567679

Source:http://linkedlifedata.com/resource/pubmed/id/14567679

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
42
pubmed:dateCreated
2003-10-21
pubmed:abstractText
The lysophospholipids, lysophosphatidic acid, sphingosine-1-phosphate, and sphingosylphosphorylcholine (SPC), are bioactive lipid molecules that regulate diverse biological processes. Although the specific G protein-coupled receptors for lysophosphatidic acid and sphingosine-1-phosphate have been well-characterized, much less is known of the SPC receptors. It has been reported that ovarian cancer G protein-coupled receptor 1 (OGR1) is a high affinity receptor for SPC, and its closely related homologue GPR4 is a high affinity receptor for SPC with low affinity for lysophosphatidylcholine (LPC). However, in a functional assay to examine the specificity of ligand binding, we found that neither SPC nor LPC, or other related lysophospholipids, induced internalization of GPR4 from the plasma membrane. In agreement, these lysolipids also did not induce translocation of beta-arrestin2-GFP from the cytosol to the plasma membrane in GPR4 expressing cells. However, when these cells were cotransfected with G protein-coupled receptor kinase 2, in the absence of added ligands, beta-arrestin2-GFP accumulated in cytoplasmic vesicles, reminiscent of vesicular labeling usually observed after agonist stimulation of GPCRs. In addition, neither SPC nor LPC stimulated the binding of GTPgammaS to membranes prepared from GPR4 expressing cells and did not activate ERK1/2. Surprisingly, enforced expression of GPR4 inhibited activation of ERK1/2 induced by several stimuli, including SPC, sphingosine-1-phosphate, and even EGF. Collectively, our results suggest that SPC and LPC are not the ligands for GPR4 and that this receptor may constitutively inhibit ERK1/2 activation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12181-91
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
The G protein-coupled receptor GPR4 suppresses ERK activation in a ligand-independent manner.
pubmed:affiliation
Department of Biochemistry, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't