The protein tyrosine phosphatase SHP-2 negatively regulates ciliary neurotrophic factor induction of gene expression

Abstract

Ciliary neurotrophic factor, along with other neuropoietic cytokines, signals through the shared receptor subunit gp130 [1-3], leading to the tyrosine phosphorylation of a number of substrates [4,5], including the transcription factors STAT1 and STAT3 and the protein tyrosine phosphatase SHP-2 [6,7] [8]. SHP-2 (also known as PTP1D, SHPTP2, Syp and PTP2C) is a positive regulatory molecule required for the activation of the mitogen-activated protein kinase pathway and the stimulation of gene expression in response to epidermal growth factor, insulin and platelet-derived growth factor stimulation [9-11]. We have previously shown that cytokines that signal via the gp130 receptor subunit activate transcription of the vasoactive intestinal peptide (VIP) gene through a 180 bp cytokine response element (CyRE) [12,13]. To characterize the role of SHP-2 in the regulation of gp130-stimulated gene expression, we examined the regulation of the VIP CyRE in two systems that prevented ligand-dependent SHP-2 phosphorylation. Inhibition of SHP-2, either by mutating the tyrosine residue in gp130 that mediates the SHP-2 interaction, or by expression of dominant-negative SHP-2, resulted in dramatic increases in gp130-dependent gene expression, through the VIP CyRE and more specifically through multimerized STAT-binding sites. These data suggest that SHP-2 has a negative role in gp130 signaling by modulating STAT-mediated transcriptional activation.

Interleukin-6 and oncostatin M-induced growth inhibition of human A375 melanoma cells is STAT-dependent and involves upregulation of the cyclin-dependent kinase inhibitor p27/Kip1

“…Moreover, activation of SHP-2 without concomitant STAT activation did not in¯uence the growth behavior of A375 transfectants. It will be of interest to determine whether SHP-2 may play an inhibitory role for gp130-signaling in these cells, as has been shown for other cell types (Kim et al, 1998;Schaper et al, 1998;Symes et al, 1997). This could explain why transfectants expressing the receptors Y767 and Y814 showed no apparent decrease of the STAT signal within the ®rst hour, while DNA binding activity induced by the full-length EG construct or by wild-type gp130 dramatically decreased between 30 and 60 min after stimulation.…”

“…The tyrosine phosphatase SHP-2 also binds to a speci®c phosphotyrosine motif of gp130 (Stahl et al, 1995), thereby possibly forming a link to the Ras/Raf/MAP kinase pathway, also known to be activated by IL-6-type cytokines (Boulton et al, 1994;Kumar et al, 1994). Activation of the SHP-2 phosphatase may further lead to downregulation of the signal (Kim et al, 1998;Symes et al, 1997). In addition, other molecules such as vav (Lee et al, 1997) or tyrosine kinases Hck (Ernst et al, 1994), Tec, Btk (Matsuda et al, 1995b) and Fes (Matsuda et al, 1995a) have been reported to become phosphorylated upon gp130 stimulation, but their contribution to signal transduction is unclear.…”

Inhibitors of Cytokine Signal Transduction

“…SHP-2, on the other hand, appears to function mainly as a positive regulator of signaling (for review see Ref. 17), although there is evidence to suggest that it can inhibit cytokine signaling via the gp130 receptor (18).…”

Modulation of hepatic acute phase gene expression by epidermal growth factor and src protein tyrosine kinases in murine and human hepatic cells

“…Recruitment of SHP-2 to gp130 is believed to contribute to down-modulated signaling by gp130, in part by the phosphatase action. 48,69 To show that Csk-sensitive Src kinases, in principle, could target gp130 by modifying the Y2 site, we determined the effects of Csk on signaling mediated by the cytoplasmic domain of gp130 that contained the wild-type or the tyrosine to phenylalanine mutant (Y2F) SHP-2 binding site. We introduced into HepG2 cells the expression of the chimeric G-CSFR-gp130 receptors that carried the cytoplasmic domain of gp130 with or without the Y2F mutation.…”