scholarly journals Discordant Effects of Glucosamine on Insulin-stimulated Glucose Metabolism and Phosphatidylinositol 3-Kinase Activity

1999 ◽  
Vol 274 (44) ◽  
pp. 31312-31319 ◽  
Author(s):  
Meredith Hawkins ◽  
Meizhu Hu ◽  
Jinghua Yu ◽  
Howard Eder ◽  
Patricia Vuguin ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Kinase Activity ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

scholarly journals Phosphatidylinositol 3-Kinase Activity Is Critical for Glucose Metabolism and Embryo Survival in Murine Blastocysts

2005 ◽  
Vol 281 (9) ◽  
pp. 6010-6019 ◽  
Author(s):  
Joan K. Riley ◽  
Mary O. Carayannopoulos ◽  
Amanda H. Wyman ◽  
Maggie Chi ◽  
Kelle H. Moley
Keyword(s):  
Glucose Metabolism ◽  
Kinase Activity ◽  
Phosphatidylinositol 3 Kinase ◽  
Embryo Survival ◽  
Phosphatidylinositol 3

Long-chain n-3 polyunsaturated fatty acids dissociate phosphorylation of Akt from phosphatidylinositol 3′-kinase activity in rats

2007 ◽  
Vol 292 (4) ◽  
pp. E1223-E1230 ◽  
Author(s):  
Christelle Le Foll ◽  
Charlotte Corporeau ◽  
Valérie Le Guen ◽  
Jean-Paul Gouygou ◽  
Jean-Pascal Bergé ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Glucose Metabolism ◽  
Polyunsaturated Fatty Acids ◽  
Kinase Activity ◽  
Control Diet ◽  
Metabolizable Energy ◽  
Oral Glucose ◽  
Phosphatidylinositol 3 Kinase ◽  
Long Chain ◽  
Phosphatidylinositol 3

We examined whether a low amount of dietary long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) modulated phosphatidylinositol 3′-kinase (PI 3-kinase) activity and downstream Akt phosphorylation differently in normal or insulin-resistant rats. Rats were fed for 28 days with either a control diet containing 14.6% of metabolizable energy (ME) as peanut-rape oil (PR) or an n-3 diet where 4.9% of ME as PR was replaced by fish oil. Over the last 5 days, rats received 9‰ NaCl or dexamethasone (1 mg/kg). Insulin stimulation of both PI 3-kinase activity and Akt serine473 phosphorylation and modulation of GLUT4 content were studied in liver, muscle, and adipose tissue (AT). Glucose tolerance and insulin sensitivity were determined by an oral glucose challenge. In muscle and AT, LC n-3 PUFA abolished insulin-stimulated PI 3-kinase activity. These effects were not paralleled by defects in Akt serine473 phosphorylation, which was even increased in AT. Dexamethasone abolished insulin-stimulated PI 3-kinase activity in all tissues, whereas Akt serine473 phosphorylation was markedly reduced in muscle but unaltered in liver and AT. Such tissue-specific dissociating effects of LC n-3 PUFA on PI 3-kinase/Akt activation took place without alteration of glucose metabolism. Maintenance of a normal glucose metabolism by the n-3 diet despite abolition of PI 3-kinase activation was likely explained by a compensatory downstream Akt serine473 phosphorylation. The inability of LC n-3 PUFA to prevent insulin resistance by dexamethasone could result from the lack of such a dissociation.

scholarly journals Inhibition of phosphatidylinositol 3-kinase activity by association with 14-3-3 proteins in T cells.

1995 ◽  
Vol 92 (22) ◽  
pp. 10142-10146 ◽  
Author(s):  
N. Bonnefoy-Berard ◽  
Y. C. Liu ◽  
M. von Willebrand ◽  
A. Sung ◽  
C. Elly ◽  
...  
Keyword(s):  
T Cells ◽  
Kinase Activity ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

Phosphatidylinositol 3-kinase activation is mediated by high-affinity interactions between distinct domains within the p110 and p85 subunits

1994 ◽  
Vol 14 (1) ◽  
pp. 42-49
Author(s):  
K H Holt ◽  
L Olson ◽  
W S Moye-Rowley ◽  
J E Pessin
Keyword(s):  
Gene Fusion ◽  
Kinase Activity ◽  
Expression System ◽  
Sh2 Domain ◽  
Full Length ◽  
Transactivation Domain ◽  
Phosphatidylinositol 3 Kinase ◽  
Sh2 Domains ◽  
Amino Terminal ◽  
Phosphatidylinositol 3

Domains of interaction between the p85 and p110 subunits of phosphatidylinositol 3-kinase (PI 3-kinase) were studied with the yeast two-hybrid expression system. A gene fusion between the GAL4 transactivation domain and p85 activated transcription from a GAL1-lacZ reporter gene when complemented with a gene fusion between the GAL4 DNA binding domain and p110. To define subdomains responsible for this interaction, a series of p85 deletion mutants were analyzed. A 192-amino-acid inter-SH2 (IS) fragment (residues 429 to 621) was the smallest determinant identified that specifically associated with p110. In analogous experiments, the subdomain within p110 responsible for interaction with p85 was localized to an EcoRI fragment encoding the amino-terminal 127 residues. Expression of these two subdomains [p85(IS) with p110RI] resulted in 100-fold greater reporter activity than that obtained with full-length p85 and p110. Although the p85(IS) domain conferred a strong interaction with the p110 catalytic subunit, this region was not sufficient to impart phosphotyrosine peptide stimulation of PI 3-kinase activity. In contrast, coexpression of the p110 subunit with full-length p85 or with constructs containing the IS sequences flanked by both SH2 domains of p85 [p85(n/cSH2)] or either of the individual SH2 domains [p85(nSH2+IS) or p85(IS+cSH2)] resulted in PI 3-kinase activity that was activated by a phosphotyrosine peptide. These data suggest that phosphotyrosine peptide binding to either SH2 domain generates an intramolecular signal propagated through the IS region to allosterically activate p110.

scholarly journals Association of phosphatidylinositol 3-kinase with the insulin receptor: compartmentation in rat liver

2000 ◽  
Vol 279 (2) ◽  
pp. E266-E274 ◽  
Author(s):  
Paul G. Drake ◽  
Alejandro Balbis ◽  
Jiong Wu ◽  
John J. M. Bergeron ◽  
Barry I. Posner
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Insulin Receptor ◽  
Rat Liver ◽  
Intracellular Signaling ◽  
Kinase Activity ◽  
Glycogen Synthase ◽  
Metabolic Effects ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

Phosphatidylinositol 3-kinase (PI 3-kinase) plays an important role in a variety of hormone and growth factor-mediated intracellular signaling cascades and has been implicated in the regulation of a number of metabolic effects of insulin, including glucose transport and glycogen synthase activation. In the present study we have examined 1) the association of PI 3-kinase with the insulin receptor kinase (IRK) in rat liver and 2) the subcellular distribution of PI 3-kinase-IRK interaction. Insulin treatment promoted a rapid and pronounced recruitment of PI 3-kinase to IRKs located at the plasma membrane, whereas no increase in association with endosomal IRKs was observed. In contrast to IRS-1-associated PI 3-kinase activity, association of PI 3-kinase with the plasma membrane IRK did not augment the specific activity of the lipid kinase. With use of the selective PI 3-kinase inhibitor wortmannin, our data suggest that the cell surface IRK β-subunit is not a substrate for the serine kinase activity of PI 3-kinase. The functional significance for the insulin-stimulated selective recruitment of PI 3-kinase to cell surface IRKs remains to be elucidated.

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