Linked Life Data

9063453

Source:http://linkedlifedata.com/resource/pubmed/id/9063453

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1997-4-7
pubmed:abstractText
Dictyostelium cells have enzyme activities that generate the inositol polyphosphate Ins(1,4,5)P3 from Ins(1,3,4,5,6)P5 via the intermediates Ins(1,3,4,5)P4 and Ins(1,4,5,6)P4. These enzyme activities could explain why cells with a deletion of the single phospholipase C gene (plc- cells) possess nearly normal Ins(1,4,5)P3 levels. In this study the regulation and the subcellular localization of the enzyme activities was investigated. The enzyme activities performing the different reaction steps from Ins(1,3,4,5,6)P5 to Ins(1,4,5)P3 are probably due to a single enzyme. Indications for this are the previously shown similar Ca2+ dependencies of the various reaction steps. Furthermore, the activities mediating the complete conversion of Ins(1,3,4,5,6)P5 to Ins(1,4,5)P3 co-purify after subcellular fractionation, solubilization, and chromatography of the proteins. Subcellular fractionation studies demonstrate that the enzyme is localized mainly at the inner face of the plasma membrane. The enzyme activity could not be stimulated in vitro by guanosine 5'-(3-thio)triphosphate, a procedure known to activate G-protein-coupled enzymes in Dictyostelium. Still, in plc- cells the level of Ins(1,4,5)P3 was increased significantly after stimulation with high concentrations of the extracellular ligand cAMP. This stimulation is most likely due to the influx of Ca2+ because no increase of Ins(1,4,5)P3 could be detected in the absence of extracellular Ca2+. The results demonstrate the existence of a new receptor-controlled route for the formation of Ins(1,4,5)P3 that is independent of phospholipase C.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
244
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
113-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Phospholipase-C-independent inositol 1,4,5-trisphosphate formation in Dictyostelium cells. Activation of a plasma-membrane-bound phosphatase by receptor-stimulated Ca2+ influx.
pubmed:affiliation
Department of Biochemistry, University of Groningen, The Netherlands.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't