IL-13 induces tyrosine phosphorylation of phospholipase C gamma-1 following IRS-2 association in human monocytes: relationship with the inhibitory effect of IL-13 on ROI production.

Here we analysed the involvement of tyrosine phosphorylation in the regulation of the initial molecular events induced by IL-13 to modulate TPA-triggered reactive oxygen intermediates (ROI) production. Our data indicate that treatment of monocytes with a protein tyrosine kinase inhibitor (herbimycin A) prevents IL-13-induced cAMP accumulation and subsequent ROI inhibition. We have previously demonstrated that cAMP accumulation depends on inositol phosphates hydrolysis (InsPs) and intracellular Ca2+ mobilisation. The inhibition of InsPs and intracellular Ca2+ release by herbimycin A suggests a primary role of tyrosine kinases upstream PLC activation. We further specify that IL-13 stimulates PLC-gamma 1 and IRS-2 tyrosine phosphorylation in human monocytes. We demonstrate for the first time that IL-13 induces the association of IRS-2 with PLC-gamma 1. We proposed here that PLC-gamma 1 is a new candidate recruited by IRS-2.