Rules of engagement: distinct functions for the four class I PI3K catalytic isoforms in immunity

摘要

Mammalian cells can express up to 4 different class I PI3K isoforms, each of which is engaged by tyrosine kinases or G-protein coupled receptors (GPCRs) to generate the second messenger signaling molecule PtdIns(3,4,5)P3 (PIP3). The p110α and p110β isoforms are relatively widely expressed, whereas p110γ and p110δ are more highly expressed in cells of the immune system than in other cell types. Nevertheless, each of the 4 class I PI3Ks have been shown to participate in the orchestration of the signaling events that lead to immune cell development, control of gene expression, skewing towards individual cell lineage subsets and proliferation.