Linked Life Data

2166043

Source:http://linkedlifedata.com/resource/pubmed/id/2166043

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
1990-9-13
pubmed:abstractText
Phosphorylation of hormone receptors by protein kinase C (PKC) may be involved in the regulation of receptor recycling. We have studied the recycling and the phosphorylation state of the insulin growth factor (IGF) II/mannose 6-phosphate (Man-6-P) receptor in microvascular endothelial cells from rat adipose tissue. Scatchard analysis showed these cells have over 2 x 10(6) receptors/cell with an affinity constant of 1 x 10(9) M-1. In the presence of phorbol myristate acetate (PMA), an activator of PKC and analog of diacylglycerol, IGF-II receptor number increased in the plasma membrane by 60% without changes in the binding affinity. This increase in cell surface receptor number was confirmed by affinity cross-linking and 125I-surface labeling studies, occurred with a half-time of 20 min, and was reversible upon withdrawal of PMA. The redistribution of IGF-II/Man-6-P receptors was not due to an inhibition of internalization which was in fact stimulated by PMA. The effect of PMA on IGF-II receptor recycling correlated with its stimulation of PKC activity. Furthermore, after down-regulation of cellular PKC levels by preincubation with PMA, PMA was unable to activate residual PKC activity in the membranous pool or increase IGF-II receptor number at the cell surface. The phosphorylation state of the IGF-II/Man-6-P receptor was determined by 32P labeling of intact cells and immunoprecipitation with anti-receptor antibodies. In the basal state, the receptor was phosphorylated only on serine residues which was increased by 75% after treatment with PMA. In contrast, IGF-II decreased receptor phosphorylation and plasma membrane binding in a parallel and dose-dependent manner. Thus, PKC-stimulated serine phosphorylation of IGF-II/Man-6-P receptor may promote the translocation of the receptor to the cell surface, whereas IGF-II-stimulated dephosphorylation of the receptor may lead to a decrease in the number of cell surface receptors. These data suggest a role for PKC-mediated serine phosphorylation in the regulation of intracellular trafficking of receptors in endothelial cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
265
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13864-70
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:2166043-Adipose Tissue, pubmed-meshheading:2166043-Amino Acids, pubmed-meshheading:2166043-Animals, pubmed-meshheading:2166043-Endothelium, Vascular, pubmed-meshheading:2166043-Hexosephosphates, pubmed-meshheading:2166043-Insulin-Like Growth Factor II, pubmed-meshheading:2166043-Kinetics, pubmed-meshheading:2166043-Male, pubmed-meshheading:2166043-Mannosephosphates, pubmed-meshheading:2166043-Microcirculation, pubmed-meshheading:2166043-Phosphorylation, pubmed-meshheading:2166043-Protein Kinase C, pubmed-meshheading:2166043-Rats, pubmed-meshheading:2166043-Receptor, IGF Type 2, pubmed-meshheading:2166043-Receptors, Cell Surface, pubmed-meshheading:2166043-Receptors, Somatomedin, pubmed-meshheading:2166043-Somatomedins, pubmed-meshheading:2166043-Temperature, pubmed-meshheading:2166043-Tetradecanoylphorbol Acetate
pubmed:year
1990
pubmed:articleTitle
Modulation of the insulin growth factor II/mannose 6-phosphate receptor in microvascular endothelial cells by phorbol ester via protein kinase C.
pubmed:affiliation
Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02215.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.