Document Detail


Stable activation of phosphatidylinositol 3-kinase in the T cell immunological synapse stimulates Akt signaling to FoxO1 nuclear exclusion and cell growth control.
MedLine Citation:
PMID:  15778376     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We have previously reported at the single cell level that PI3K is activated after conjugate formation between T lymphocytes and APCs. However, in contrast to cells exposed to an asymmetrical signal that usually increase 3'-phosphoinositides (3'-PI) transiently in the region of the activated receptors, T cells contacting APC accumulate 3'-PI across their whole plasma membrane far beyond the region of the immunological synapse (IS). Importantly, this effect is maintained over time, for hours, and although PI3K-dependent pathways translate in various cell types extracellular stimuli into a wide range of biological events, in primary T cells this stability is mostly required for cell division induced by Ag. Using imaging methodologies, the present article elucidates the molecular mechanisms responsible for this particular functioning of the PI3K pathway in primary human T lymphocytes interacting with APCs, especially with dendritic cells. The results reveal that the IS unremittingly recruits PI3K to maintain high 3'-PI levels in T cells through phosphotyrosine-dependent mechanisms, suggesting a major participation of class Ia PI3K. This persistent activation of PI3K results in the Akt-dependent sequestration of the FoxO transcription factor, FoxO1, outside the nucleus of T cells interacting with APCs. Using an active form of FoxO1, we demonstrate that this compartmentalization process can affect T cell growth after Ag recognition. We conclude that the need for sustained PI3K signaling within the consolidated IS is probably an undemanding tactic used by primary T cells critical for initiating cell cycle progression through the prolonged inactivation of FoxO1, one important factor that can control cell quiescence.
Authors:
Stéphanie Fabre; Valérie Lang; Julie Harriague; Aude Jobart; Terry G Unterman; Alain Trautmann; Georges Bismuth
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of immunology (Baltimore, Md. : 1950)     Volume:  174     ISSN:  0022-1767     ISO Abbreviation:  J. Immunol.     Publication Date:  2005 Apr 
Date Detail:
Created Date:  2005-03-21     Completed Date:  2005-06-07     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  2985117R     Medline TA:  J Immunol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4161-71     Citation Subset:  AIM; IM    
Affiliation:
Département de Biologie Cellulaire, Institut Cochin, Institut National de la Santé et de la Recherche Médicale, Unité 567, Centre National de la Recherche Scientifique, Université René Descartes, Paris, France.
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MeSH Terms
Descriptor/Qualifier:
1-Phosphatidylinositol 3-Kinase / metabolism*
Active Transport, Cell Nucleus
Antigen-Presenting Cells
Cell Communication
Cell Proliferation*
DNA-Binding Proteins / metabolism*
Enzyme Activation
Forkhead Transcription Factors
Humans
Phosphatidylinositol Phosphates / metabolism
Protein Transport
Protein-Serine-Threonine Kinases / physiology*
Proto-Oncogene Proteins / physiology*
Proto-Oncogene Proteins c-akt
Signal Transduction
T-Lymphocytes / enzymology*,  immunology*
Transcription Factors / metabolism*
Grant Support
ID/Acronym/Agency:
DK41430/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/DNA-Binding Proteins; 0/FOXO1 protein, human; 0/Forkhead Transcription Factors; 0/Phosphatidylinositol Phosphates; 0/Proto-Oncogene Proteins; 0/Transcription Factors; 0/phosphatidylinositol 3,4,5-triphosphate; EC 2.7.1.137/1-Phosphatidylinositol 3-Kinase; EC 2.7.1.37/AKT1 protein, human; EC 2.7.11.1/Protein-Serine-Threonine Kinases; EC 2.7.11.1/Proto-Oncogene Proteins c-akt

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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