Phospholipase D pathway modulates key signaling events in activated T cells

Abstract

The T cell receptor (TCR) triggers several intracellular signaling events that are crucial for proper T cell development and function. The aim of the present work was to study the participation of the phospholipase D (PLD) pathway in signaling events elicited by the TCR stimulation in Jurkat T cells, namely: protein kinase D 1 (PKD1), extracellular signal-regulated kinase (ERK1/2) and p21- activated kinase 1 (PAK1). To suppress phosphatidic acid (PA) and diacylglycerol (DAG) generation by the PLD pathway, cells were preincubated for 1 h with 0.4% n-butanol (since in the presence of primary alcohols PLD generates phosphatidylalcohols which cannot be further dephosphorylated to DAG) and the TCR was activated with anti-CD3 antibodies. Western blot assays showed that n-butanol treatment reduced TCR-induced PKD and PAK1 activation while ERK1/2 activation was not affected. Moreover, pull down assays showed that n-butanol also reduced Rac1 activation after 10 min of stimulation with anti-CD3. Previous reports evidenced that in activated T cells PKD phosphorylates histone deacetylase 7 (HDAC7) and induces its nuclear export allowing gene expression. In agreement with the inhibition of PKD, our results showed that n-butanol also restrained the nuclear export of EGFP-HDAC7 in activated Jurkat T cells. Thus, the PLD pathway modulates key signaling events elicited by the TCR engagement