Linked Life Data

8530362

Source:http://linkedlifedata.com/resource/pubmed/id/8530362

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
50
pubmed:dateCreated
1996-1-26
pubmed:abstractText
In an earlier study a mutant Dictyostelium cell-line (plc-) was constructed in which all phospholipase C activity was disrupted and nonfunctional, yet these cells had nearly normal Ins(1,4,5)P3 levels (Drayer, A.L., Van Der Kaay, J., Mayr, G.W, Van Haastert, P.J.M. (1990) EMBO J. 13, 1601-1609). We have now investigated if these cells have a phospholipase C-independent de novo pathway of Ins(1,4,5)P3 synthesis. We found that homogenates of plc- cells produce Ins(1,4,5)P3 from endogenous precursors. The enzyme activities that performed these reactions were located in the particulate cell fraction, whereas the endogenous substrate was soluble and could be degraded by phytase. We tested various potential inositol polyphosphate precursors and found that the most efficient were Ins(1,3,4,5,6)P5, Ins(1,3,4,5)P4, and Ins(1,4,5,6)P4. The utilization of Ins(1,3,4,5,6)P5, which can be formed independently of phospholipase C by direct phosphorylation of inositol (Stephens, L.R. and Irvine, R.F. (1990) Nature 346, 580-582), provides Dictyostelium with an alternative and novel pathway of de novo Ins(1,4,5)P3 synthesis. We further discovered that Ins(1,3,4,5,6)P5 was converted to Ins(1,4,5)P3 via both Ins(1,3,4,5)P4 and Ins(1,4,5,6)P4. In the absence of calcium no Ins(1,4,5)P3 formation could be observed; half-maximal activity was observed at low micromolar calcium concentrations. These reaction steps could also be performed by a single enzyme purified from rat liver, namely, the multiple inositol polyphosphate phosphatase. These data indicate that organisms as diverse as rat and Dictyostelium possess enzyme activities capable of synthesizing the second messengers Ins(1,4,5)P3 and Ins(1,3,4,5)P4 via a novel phospholipase C-independent pathway.
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
15
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
29724-31
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:8530362-Animals, pubmed-meshheading:8530362-Calcium, pubmed-meshheading:8530362-Chromatography, High Pressure Liquid, pubmed-meshheading:8530362-Dictyostelium, pubmed-meshheading:8530362-Hydrolysis, pubmed-meshheading:8530362-Inositol 1,4,5-Trisphosphate, pubmed-meshheading:8530362-Inositol Phosphates, pubmed-meshheading:8530362-Kinetics, pubmed-meshheading:8530362-Liver, pubmed-meshheading:8530362-Models, Biological, pubmed-meshheading:8530362-Molecular Conformation, pubmed-meshheading:8530362-Molecular Structure, pubmed-meshheading:8530362-Phosphoric Monoester Hydrolases, pubmed-meshheading:8530362-Phosphotransferases (Alcohol Group Acceptor), pubmed-meshheading:8530362-Rats, pubmed-meshheading:8530362-Subcellular Fractions, pubmed-meshheading:8530362-Type C Phospholipases
pubmed:year
1995
pubmed:articleTitle
A novel, phospholipase C-independent pathway of inositol 1,4,5-trisphosphate formation in Dictyostelium and rat liver.
pubmed:affiliation
Department of Biochemistry, University of Groningen, The Netherlands.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't