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Mol. Cell. Biol., 09 1996, 4710-4716, Vol 16, No. 9
JB Demoulin, C Uyttenhove, E Van Roost, B DeLestre, D Donckers, J Van Snick and JC Renauld
Interleukin-9 (IL-9), a T-cell-derived cytokine, interacts with a specific
receptor associated with the IL-2 receptor gamma chain. In this report, we
analyze the functional domains of the human IL-9 receptor transfected into
mouse lymphoid cell lines. Three different functions were examined: growth
stimulation in factor-dependent pro-B Ba/F3 cells, protection against
dexamethasone-induced apoptosis, and Ly- 6A2 induction in BW5147 lymphoma
cells. The results indicated that a single tyrosine, at position 116 in the
cytoplasmic domain, was required for all three activities. In addition, we
observed that human IL-9 reduced the proliferation rate of transfected
BW5147 cells, an effect also dependent on the same tyrosine. This amino
acid was necessary for IL-9-mediated tyrosine phosphorylation of the
receptor and for STAT activation but not for IRS-2/4PS activation or for
JAK1 phosphorylation, which depended on a domain closer to the plasma
membrane. We also showed that JAK1 was constitutively associated with the
IL-9 receptor. Activated STAT complexes induced by IL-9 were found to
contain STAT1, STAT3, and STAT5 transcription factors. Moreover, sequence
homologies between human IL-9 receptor tyrosine 116 and tyrosines (of other
receptors activating STAT3 and STAT5 were observed. Taken together, these
data indicate that a single tyrosine of the IL-9 receptor, required for
activation of three different STAT proteins, is necessary for distinct
activities of this cytokine, including proliferative responses.
Copyright © 1996, American Society for Microbiology
A single tyrosine of the interleukin-9 (IL-9) receptor is required for STAT activation, antiapoptotic activity, and growth regulation by IL-9
Brussels Branch, Ludwig Institute for Cancer Research, Brussels, Belgium.
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