scholarly journals Phosphatidylinositol 3-Kinase Potentiates, but Does Not Trigger, T Cell Proliferation Mediated by the IL-2 Receptor

2001 ◽  
Vol 167 (5) ◽  
pp. 2714-2723 ◽  
Author(s):  
James J. Moon ◽  
Brad H. Nelson
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
T Cell Proliferation ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

scholarly journals A Late, Prolonged Activation of the Phosphatidylinositol 3-Kinase Pathway Is Required for T Cell Proliferation

2004 ◽  
Vol 172 (6) ◽  
pp. 3527-3534 ◽  
Author(s):  
Ferdinand V. Lali ◽  
James Crawley ◽  
Derek A. McCulloch ◽  
Brian M. J. Foxwell
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
T Cell Proliferation ◽  
Phosphatidylinositol 3 Kinase ◽  
Kinase Pathway ◽  
Phosphatidylinositol 3

scholarly journals Activation of pp70/85 S6 kinases in interleukin-2-responsive lymphoid cells is mediated by phosphatidylinositol 3-kinase and inhibited by cyclic AMP.

1995 ◽  
Vol 15 (1) ◽  
pp. 326-337 ◽  
Author(s):  
M Monfar ◽  
K P Lemon ◽  
T C Grammer ◽  
L Cheatham ◽  
J Chung ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Phorbol Ester ◽  
Interleukin 2 ◽  
Signalling Pathway ◽  
Phosphatidylinositol 3 Kinase ◽  
Cell Proliferation Inhibition ◽  
Phosphatidylinositol 3

Activation of phosphatidylinositol 3-kinase (PI3K) and activation of the 70/85-kDa S6 protein kinases (alpha II and alpha I isoforms, referred to collectively as pp70S6k) have been independently linked to the regulation of cell proliferation. We demonstrate that these kinases lie on the same signalling pathway and that PI3K mediates the activation of pp70 by the cytokine interleukin-2 (IL-2). We also show that the activation of pp70S6k can be blocked at different points along the signalling pathway by using specific inhibitors of T-cell proliferation. Inhibition of PI3K activity with structurally unrelated but highly specific PI3K inhibitors (wortmannin or LY294002) results in inhibition of IL-2-dependent but not phorbol ester (conventional protein kinase C [cPKC])-dependent pp70S6k activation. The T-cell immunosuppressant rapamycin potently antagonizes IL-2-(PI3K)- and phorbol ester (cPKC)-mediated activation of pp70S6k. Thus, wortmannin and rapamycin antagonize IL-2-mediated activation of pp70S6k at distinct points along the PI3K-regulated signalling pathway, or rapamycin antagonizes another pathway required for pp70S6k activity. Agents that raise the concentration of intracellular cyclic AMP (cAMP) and activate cAMP-dependent protein kinase (PKA) also inhibit IL-2-dependent activation of pp70S6k. In this case, inhibition appears to occur at least two points in this signalling path. Like rapamycin, PKA appears to act downstream of cPKC-mediated pp70S6k activation, and like wortmannin, PKA antagonizes IL-2-dependent activation of PI3K. The results with rapamycin and wortmannin are of added interest since the yeast and mammalian rapamycin targets resemble PI3K in the catalytic domain.

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