Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
51
pubmed:dateCreated
1995-1-24
pubmed:abstractText
The effect of phosphoinositides on the activity of protein kinase C (PKC) isotypes was investigated. PKC alpha, beta I, beta II, gamma, delta, epsilon, eta, and zeta were expressed in baculovirus-infected insect cells and purified by column chromatography. The calcium-activated PKC isotypes alpha, beta I, beta II, and gamma were not significantly activated by any of the phosphoinositides investigated (phosphatidylinositol-4-phosphate (PtdIns-4-P), PtdIns-3-P, PtdIns-4,5-P2, PtdIns-3,4-P2, and PtdIns-3,4,5-P3) when added in the presence of concentrations of phosphatidylserine that give maximal stimulation. The calcium-insensitive PKC isotypes delta, epsilon, and theta also showed little response to PtdIns-3-P, PtdIns-4-P, or PtdIns-4,5-P2 when these lipids were added in the presence of phosphatidylserine. In contrast, PtdIns-3,4-P2 and PtdIns-3,4,5-P3 caused a 5-15-fold stimulation of these enzymes compared with phosphatidylserine alone. 50% maximal stimulation of PKC epsilon by PtdIns-3,4,5-P3 occurred when this lipid was present at about 1% of the carrier PtdIns-4,5-P2 (about 100 nM). These lipids had little effect on baculovirus-expressed PKC zeta, which was constitutively active. A short chain version of PtdIns-3,4,5-P3, dioctanoyl-PtdIns-3,4,5-P3, activated PKC delta, epsilon, and eta in the absence of other lipids, whereas a short chain version of PtdIns-4,5-P2, dihexanoyl-PtdIns-4,5-P2, did not. Since PtdIns-3,4-P2 and PtdIns-3,4,5-P3 are nominally absent in unstimulated cells and appear within seconds to minutes of stimulation by various cell activators, these lipids could act as second messengers to activate PKC delta, epsilon, or eta in vivo.
pubmed:grant
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
23
pubmed:volume
269
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
32358-67
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Activation of protein kinase C family members by the novel polyphosphoinositides PtdIns-3,4-P2 and PtdIns-3,4,5-P3.
pubmed:affiliation
Department of Medicine, Beth Israel Hospital.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't