Linked Life Data

10358930

Source:http://linkedlifedata.com/resource/pubmed/id/10358930

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1999-6-28
pubmed:abstractText
Phosphoinositide 3-kinase (PI 3-kinase) is a key signaling enzyme implicated in a variety of receptor-stimulated cell responses. Stimulation of receptors possessing (or coupling to) protein-tyrosine kinase activates heterodimeric PI 3-kinases, which consist of an 85-kDa regulatory subunit (p85) containing Src-homology 2 (SH2) domains and a 110-kDa catalytic subunit (p110 alpha or p110 beta). Thus, this form of PI 3-kinases could be activated in vitro by a phosphotyrosyl peptide containing a YMXM motif that binds to the SH2 domains of p85. Receptors coupling to alpha beta gamma-trimeric G proteins also stimulate the lipid kinase activity of a novel p110 gamma isoform, which is not associated with p85, and thereby is not activated by tyrosine kinase receptors. The activation of p110 gamma PI 3-kinase appears to be mediated through the beta gamma subunits of the G protein (G beta gamma). In addition, rat liver heterodimeric PI 3-kinases containing the p110 beta catalytic subunit are synergistically activated by the phosphotyrosyl peptide plus G beta gamma. Such enzymatic properties were also observed with a recombinant p110 beta/p85 alpha expressed in COS-7 cells. In contrast, another heterodimeric PI 3-kinase consisting of p110 alpha and p85 in the same rat liver, together with a recombinant p110 alpha/p85 alpha, was not activated by G beta gamma, though their activities were stimulated by the phosphotyrosyl peptide. Synergistic activation of PI 3-kinase by the stimulation of the two major receptor types was indeed observed in intact cells, such as chemotactic peptide (N-formyl-Met-Leu-Phe) plus insulin (or Fc gamma II) receptors in differentiated THP-1 and CHO cells and adenosine (A1) plus insulin receptors in rat adipocytes. Thus, PI 3-kinase isoforms consisting of p110 beta catalytic and SH2-containing (p85 or its related) regulatory subunits appeared to function as a 'cross-talk' enzyme between the two signal transduction pathways mediated through tyrosine kinase and G protein-coupled receptors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0009-3084
pubmed:author
pubmed:issnType
Print
pubmed:volume
98
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
79-86
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Synergistic activation of a family of phosphoinositide 3-kinase via G-protein coupled and tyrosine kinase-related receptors.
pubmed:affiliation
Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Japan. katada@mol.f.u-tokyo.ac.jp
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't