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Trends Immunol. 2007 Feb;28(2):80-7. Epub 2007 Jan 5.

Antigen receptor signalling: a distinctive role for the p110delta isoform of PI3K.

Author information

1
Laboratory of Lymphocyte Signalling and Development, Babraham Institute, Cambridge, UK, CB2 4AT. klaus.okkenhaug@bbsrc.ac.uk

Abstract

The activation of antigen receptors triggers two important signalling pathways originating from phosphatidylinositol(4,5)-bisphosphate [PtdIns(4,5)P(2)]. The first is phospholipase Cgamma (PLCgamma)-mediated hydrolysis of PtdIns(4,5)P(2), resulting in the activation of Ras, protein kinase C and Ca(2+) flux. This culminates in profound alterations in gene expression and effector-cell responses, including secretory granule exocytosis and cytokine production. By contrast, phosphoinositide 3-kinases (PI3Ks) phosphorylate PtdIns(4,5)P(2) to yield phosphatidylinositol(3,4,5)-trisphosphate, activating signalling pathways that overlap with PLCgamma or are PI3K-specific. Pathways that are PI3K-specific include Akt-mediated inactivation of Foxo transcription factors and transcription-independent regulation of glucose uptake and metabolism. The p110delta isoform of PI3K is the main source of PI3K activity following antigen recognition by B cells, T cells and mast cells. Here, we review the roles of p110delta in regulating antigen-dependent responses in these cell types.

PMID:
17208518
PMCID:
PMC2358943
DOI:
10.1016/j.it.2006.12.007
[Indexed for MEDLINE]
Free PMC Article

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