Linked Life Data

1648089

Source:http://linkedlifedata.com/resource/pubmed/id/1648089

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
1991-8-7
pubmed:abstractText
Phosphorylation of the adipocyte lipid-binding protein (ALBP) isolated from 3T3-L1 cells has been studied in vitro utilizing the wheat germ agglutinin-purified 3T3-L1 adipocyte insulin receptor and the soluble kinase domain of the human insulin receptor. Following insulin-stimulated, ATP-dependent autophosphorylation of the wheat germ agglutinin-purified receptor beta-subunit, ALBP was phosphorylated exclusively on tyrosine 19 in the sequence Glu-Asn-Phe-Asp-Asp-Tyr19, analogous to the substrate phosphorylation consensus sequence observed for several tyrosyl kinases. The concentration of insulin necessary for half-maximal receptor autophosphorylation (KIR0.5) was identical to that necessary for half-maximal ALBP phosphorylation (KALBP0.5), 10 nM. Kinetic analysis indicated that stimulation of ALBP phosphorylation by insulin was attributable to a 5-fold increase in the Vmax (to 0.33 fmol/min/fmol insulin-binding sites) while the Km for ALBP was largely unaffected. By utilizing the soluble kinase domain of the human receptor beta-subunit, the presence of oleate bound to ALBP increased the kcat/Km greater than 3-fold. Oleate dramatically inhibited autophosphorylation of the 38-kDa fragment of the soluble receptor kinase in a concentration dependent fashion (I0.5 approximately 4 microM). The 48-kDa kinase exhibited much less sensitivity to the effects of oleate (I0.5 approximately 190 microM). The inhibition of autophosphorylation of the 48-kDa soluble kinase by oleate was reversed by adding saturating levels of ALBP. These results demonstrate that in vitro the murine adipocyte lipid-binding protein is phosphorylated on tyrosine 19 in an insulin-stimulated fashion by the insulin receptor and that the presence of a bound fatty acid on ALBP increases the affinity of insulin receptor for ALBP. Inhibition of insulin receptor kinase activity by unbound fatty acids suggests that the end products of the lipogenic pathway may feedback inhibit the tyrosyl kinase and that fatty acid-binding proteins have the potential to modulate such interaction.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
266
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12266-71
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
In vitro phosphorylation of the adipocyte lipid-binding protein (p15) by the insulin receptor. Effects of fatty acid on receptor kinase and substrate phosphorylation.
pubmed:affiliation
Department of Biochemistry, University of Minnesota, St. Paul 55108.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't