scholarly journals Role of Phosphatidylinositol 3-Kinase Activation on Insulin Action and Its Alteration in Diabetic Conditions

2007 ◽  
Vol 30 (9) ◽  
pp. 1610-1616 ◽  
Author(s):  
Tomoichiro Asano ◽  
Midori Fujishiro ◽  
Akifumi Kushiyama ◽  
Yusuke Nakatsu ◽  
Masayasu Yoneda ◽  
...  
Keyword(s):  
Insulin Action ◽  
Phosphatidylinositol 3 Kinase ◽  
Kinase Activation ◽  
Phosphatidylinositol 3

scholarly journals Phosphatidylinositol 3-kinase activity is important for progesterone-induced Xenopus oocyte maturation.

1993 ◽  
Vol 13 (11) ◽  
pp. 6661-6666 ◽  
Author(s):  
A J Muslin ◽  
A Klippel ◽  
L T Williams
Keyword(s):  
Oocyte Maturation ◽  
Kinase Activity ◽  
Sh2 Domain ◽  
Pi3 Kinase ◽  
Meiotic Maturation ◽  
Xenopus Laevis Oocytes ◽  
Phosphatidylinositol 3 Kinase ◽  
Kinase Activation ◽  
Phosphatidylinositol 3

In somatic cells, phosphatidylinositol 3-kinase (PI3 kinase) is a critical intermediary in growth factor-induced mitogenesis. We have examined the role of this enzyme in meiotic maturation of Xenopus laevis oocytes. PI3 kinase activity was present in immunoprecipitates of the p85 subunit of PI3 kinase from immature oocytes and markedly increased following progesterone stimulation. Injection of bacterially expressed protein corresponding to the C-terminal SH2 domain of p85 (SH2-C) inhibited progesterone-induced PI3 kinase activation and meiotic maturation. Injection of protein corresponding to the N-terminal SH2 domain or the SH3 domain of p85 did not inhibit PI3 kinase activation or maturation. SH2-C did not inhibit oocyte maturation induced by c-mos RNA injection. In addition, radiolabelled SH2-C was used to probe oocyte lysates, revealing that a novel 200-kDa protein bound to SH2-C. This protein may be an important mediator of progesterone-induced lipid metabolism in oocytes.

scholarly journals Role of Gab proteins in phosphatidylinositol 3-kinase activation by thrombopoietin (Tpo)

Oncogene ◽  
2001 ◽  
Vol 20 (18) ◽  
pp. 2197-2204 ◽  
Author(s):  
Didier Bouscary ◽  
Carinne Lecoq-Lafon ◽  
Stany Chrétien ◽  
Simona Zompi ◽  
Serge Fichelson ◽  
...  
Keyword(s):  
Phosphatidylinositol 3 Kinase ◽  
Kinase Activation ◽  
Phosphatidylinositol 3

scholarly journals Interleukin-2 triggers a novel phosphatidylinositol 3-kinase-dependent MEK activation pathway.

1995 ◽  
Vol 15 (6) ◽  
pp. 3049-3057 ◽  
Author(s):  
L M Karnitz ◽  
L A Burns ◽  
S L Sutor ◽  
J Blenis ◽  
R T Abraham
Keyword(s):  
Map Kinase ◽  
Interleukin 2 ◽  
Phosphatidylinositol 3 Kinase ◽  
Lipid Kinase ◽  
Kinase Activation ◽  
Activation Pathway ◽  
Drug Concentrations ◽  
Phase Entry ◽  
Phosphatidylinositol 3

Phosphatidylinositol 3-kinase (PI3-K) has been implicated as a signal-transducing component in interleukin-2 (IL-2)-induced mitogenesis. However, the function of this lipid kinase in regulating IL-2-triggered downstream events has remained obscure. Using the potent and specific PI3-K inhibitor, wortmannin, we assessed the role of PI3-K in IL-2-mediated signaling and proliferation in the murine T-cell line CTLL-2. Addition of the drug to exponentially growing cells resulted in an accumulation of cells in the G0/G1 phase of the cell cycle. Furthermore, wortmannin also partially suppressed IL-2-induced S-phase entry in G1-synchronized cells. Analysis of IL-2-triggered signaling pathways revealed that wortmannin pretreatment resulted in complete inhibition of IL-2-provoked p70 S6 kinase activation and also attenuated IL-2-induced MAP kinase activation at drug concentrations identical to those required for inhibition of PI3-K catalytic activity. Wortmannin also diminished the IL-2-triggered activation of the MAP kinase activator, MEK, but did not inhibit activation of Raf, the canonical upstream activator of MEK. These results suggest that a novel wortmannin-sensitive activation pathway regulates MEK and MAP kinase in IL-2-stimulated T lymphocytes.

Phosphatidylinositol 3-kinase activity is important for progesterone-induced Xenopus oocyte maturation

1993 ◽  
Vol 13 (11) ◽  
pp. 6661-6666
Author(s):  
A J Muslin ◽  
A Klippel ◽  
L T Williams
Keyword(s):  
Oocyte Maturation ◽  
Kinase Activity ◽  
Sh2 Domain ◽  
Pi3 Kinase ◽  
Meiotic Maturation ◽  
Xenopus Laevis Oocytes ◽  
Phosphatidylinositol 3 Kinase ◽  
Kinase Activation ◽  
Phosphatidylinositol 3

In somatic cells, phosphatidylinositol 3-kinase (PI3 kinase) is a critical intermediary in growth factor-induced mitogenesis. We have examined the role of this enzyme in meiotic maturation of Xenopus laevis oocytes. PI3 kinase activity was present in immunoprecipitates of the p85 subunit of PI3 kinase from immature oocytes and markedly increased following progesterone stimulation. Injection of bacterially expressed protein corresponding to the C-terminal SH2 domain of p85 (SH2-C) inhibited progesterone-induced PI3 kinase activation and meiotic maturation. Injection of protein corresponding to the N-terminal SH2 domain or the SH3 domain of p85 did not inhibit PI3 kinase activation or maturation. SH2-C did not inhibit oocyte maturation induced by c-mos RNA injection. In addition, radiolabelled SH2-C was used to probe oocyte lysates, revealing that a novel 200-kDa protein bound to SH2-C. This protein may be an important mediator of progesterone-induced lipid metabolism in oocytes.

Role of p70 S6 kinase in cytokine-regulated hemopoietic cell survival

1996 ◽  
Vol 74 (4) ◽  
pp. 595-600 ◽  
Author(s):  
Michael P. Scheid ◽  
Lorin Charlton ◽  
Vincent Duronio ◽  
Steven L. Pelech
Keyword(s):  
Cell Survival ◽  
Kinase Inhibitors ◽  
Phosphatidylinositol 3 Kinase ◽  
S6 Kinase ◽  
Kinase Activation ◽  
P70 S6 Kinase ◽  
Downstream Effector ◽  
Human T Cells ◽  
Phosphatidylinositol 3

The signalling mechanisms required for cell survival remain relatively undefined. We and others have shown that phosphatidylinositol 3-kinase (PI 3-kinase) is an important enzyme in the prevention of apoptosis, and this property is independent of p21ras – MAP kinase activation. It is therefore important to define the downstream targets of this enzyme mediating the inhibition of apoptosis. We report here that p70 S6 kinase, a protein critical for progression through the cell cycle and a downstream effector of PI 3-kinase, is not required for the survival of cytokine-stimulated human T-cells or murine mast cells. The potent inhibitor of p70 S6 kinase activation, rapamycin, was unable to induce apoptosis in cells stimulated with cytokines. As well, PI 3-kinase inhibitors that also blocked the activation of p70 S6 kinase were able to induce apoptosis. These studies, therefore, describe a bifurcation of signalling pathways from PI 3-kinase leading to different physiological outcomes.Key words: p70 S6 kinase, phosphatidylinositol 3-kinase, apoptosis, cytokines, wortmannin.

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