Linked Life Data

2106522

Source:http://linkedlifedata.com/resource/pubmed/id/2106522

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1990-4-9
pubmed:abstractText
Mitogenic stimulation of mammalian cells results in increased serine phosphorylation of ribosomal protein S6. Phorbol esters, which stimulate protein kinase C activity, can also increase S6 phosphorylation. In order to further investigate the role of protein kinase C in the activation S6 kinase, we studied the stimulation of an S6 kinase activity in response to phorbol ester and epinephrine in a renal epithelial cell line, Madin-Darby canine kidney cells (MDCK). In these cells, S6 phosphorylating activity in cytosolic extracts was increased following the addition of phorbol ester to the intact cells. S6 kinase and protein kinase C activities were measured in separate fractions prepared by DEAE-Sephacel fractionation of cytosolic extracts prepared from the same cells. The time course and dose-response curves for the effects of phorbol 12-myristate 13-acetate (PMA) on S6 kinase activity were similar to those for its effects on protein kinase C binding to the membrane fraction, indicating that S6 kinase activation was correlated with protein kinase C activation. Epinephrine, acting via alpha1-adrenergic receptors, also stimulated S6 kinase activity in MDCK cells; the magnitude of this effect was similar to that of PMA. However, epinephrine causes only a slight and transient association of protein kinase C with the membrane. The effect of epinephrine on S6 kinase activity, unlike that of PMA, was dependent on the presence of extracellular calcium. A23187, a calcium ionophore, could also stimulate S6 kinase activity. These results suggest that S6 kinase can be activated through more than one signaling pathway in MDCK cells. The properties of the PMA-stimulated S6 kinase were further investigated following partial purification of the enzyme. The S6 kinase was distinct from protein kinase C by several criteria. Noteably, the S6 kinase was highly specific for S6 as substrate. These results show that phorbol esters, acting through protein kinase C, stimulate the activity of a unique S6 kinase. This S6 kinase can also be activated through a signaling pathway that appears to be dependent on increased intracellular calcium.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
265
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4635-45
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:2106522-Amino Acid Sequence, pubmed-meshheading:2106522-Animals, pubmed-meshheading:2106522-Calcimycin, pubmed-meshheading:2106522-Cell Line, pubmed-meshheading:2106522-Chromatography, Ion Exchange, pubmed-meshheading:2106522-Cytosol, pubmed-meshheading:2106522-Dogs, pubmed-meshheading:2106522-Enzyme Activation, pubmed-meshheading:2106522-Epinephrine, pubmed-meshheading:2106522-Epithelium, pubmed-meshheading:2106522-Kidney, pubmed-meshheading:2106522-Kinetics, pubmed-meshheading:2106522-Molecular Sequence Data, pubmed-meshheading:2106522-Peptides, pubmed-meshheading:2106522-Protein Kinase C, pubmed-meshheading:2106522-Protein Kinase Inhibitors, pubmed-meshheading:2106522-Protein Kinases, pubmed-meshheading:2106522-Rats, pubmed-meshheading:2106522-Ribosomal Protein S6 Kinases, pubmed-meshheading:2106522-Signal Transduction, pubmed-meshheading:2106522-Substrate Specificity, pubmed-meshheading:2106522-Tetradecanoylphorbol Acetate
pubmed:year
1990
pubmed:articleTitle
Regulation of S6 kinase activity in Madin-Darby canine kidney renal epithelial cells.
pubmed:affiliation
Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle 98195.
pubmed:publicationType
Journal Article, Comparative Study