Gab2 is phosphorylatess on tyrosine upon interleukin-2/interleukin-15 stimulation in mycosis-fungoides-derived tumour T cells and associates inducibly with SHP-2 and Stat5a
Jl. Brockdorff et al., Gab2 is phosphorylatess on tyrosine upon interleukin-2/interleukin-15 stimulation in mycosis-fungoides-derived tumour T cells and associates inducibly with SHP-2 and Stat5a, EXP CLIN IM, 18(2), 2001, pp. 86-95
Cutaneous T cell lymphomas (CTCLs) often show abnormal interleukin-2 (IL-2)
receptor signaling. In this study, we investigated the role of Gab2, a rec
ently identified adaptor molecule involved in IL-2 receptor signaling in CT
CLs. We show that Gab2 was transiently phosphorylated by tyrosine in human
mycosis fungoides (MF) tumor T cells upon IL-2 stimulation and that SHP2 as
well as Stat5a associated inducibly with Gab2. IL-15, but not IL-4, also i
nduced tyrosine phosphorylation of Gab2, suggesting that the IL-2 receptor
beta -chain is important for IL-2-induced Gab2 phosphorylation. Preincubati
on of cells with the Src family kinase inhibitor, PP1, surprisingly increas
ed the IL-2- and IL-15-induced tyrosine phosphorylation of Gab2, indicating
that an Src family kinase member negatively regulates IL-2 receptor signal
ing in MF T cells. Thus, although Gaba seems to function normally in MF T c
ells compared to normal T cells, Gab2 itself might be abnormally regulated
by an Src family kinase. Copyright (C) 2001 S. Karger AG, Basel.