Involvement of an SHP-2-Rho Small G Protein Pathway in Hepatocyte Growth Factor/Scatter Factor–induced Cell Scattering

Abstract

Hepatocyte growth factor/scatter factor (HGF/SF) induces cell scattering through the tyrosine kinase-type HGF/SF receptor c-Met. We have previously shown that Rho small G protein (Rho) is involved in the HGF/SF-induced scattering of Madin-Darby canine kidney (MDCK) cells by regulating at least the assembly and disassembly of stress fibers and focal adhesions, but it remains unknown how c-Met regulates Rho activity. We have found here a novel signaling pathway of c-Met consisting of SHP-2-Rho that regulates the assembly and disassembly of stress fibers and focal adhesions in MDCK cells. SHP-2 is a protein-tyrosine phosphatase that contains src homology-2 domains. Expression of a dominant negative mutant of SHP-2 (SHP-2-C/S) markedly increased the formation of stress fibers and focal adhesions in MDCK cells and inhibited their scattering. C3, a Clostridium botulinum ADP-ribosyltransferase, and Y-27632, a specific inhibitor for ROCK, reversed the stimulatory effect of SHP-2-C/S on stress fiber formation and the inhibitory effect on cell scattering. Vav2 is a GDP/GTP exchange protein for Rho. Expression of a dominant negative mutant of Vav2 blocked the stimulatory effect of SHP-2-C/S on stress fiber formation. Conversely, expression of mutants of Vav2 that increased stress fiber formation inhibited HGF/SF-induced cell scattering. These results indicate that SHP-2 physiologically modulates the activity of Rho to form stress fibers and focal adhesions and thereby regulates HGF/SF-induced cell scattering. In addition, Vav2 may be involved in the SHP-2-Rho pathway. INTRODUCTIONCell migration is a crucial process required during a variety of biological phenomena, including normal embryonic development, wound healing, inflammatory responses, and metastasis. Hepatocyte growth factor/ scatter factor (HGF/SF) is known to induce cell migration in many types of cultured cells, including Madin-Darby canine kidney (MDCK) cells (Stoker and Gherardi, 1991). These stimulatory effects of HGF/SF are mediated through the HGF/SF receptor c-Met, which possesses tyrosine kinase activity (Bottaro et al., 1991;Naldini et al., 1991;Schlessinger, 1994). The tyrosine kinase activity of c-Met is essential for cellular responses to HGF/SF (Weidner et al., 1993;Zhu et al., 1994). Activation of c-Met tyrosine kinase induces the rapid autophosphorylation of c-Met itself as well as tyrosine phosphorylation of several cytoplasmic proteins (Rodrigues and Park, 1994;Nguyen et al., 1997).Recent studies have shown that cyclical inactivation and activation of the Rho small G protein (Rho) are involved in HGF/SF-induced cell scattering. Expression of a dominant active mutant of Rho inhibits HGF/SF-induced cell scattering (Ridley et al., 1995;Imamura et al., 1998;Kamei et al., 1999), whereas C3, a Clostridium botulinum ADP-ribosyltransferase that inhibits Rho function, or Rho GDP dissociation inhibitor, which inhibits Rho activation, blocks HGF/ SF-induced cell scattering (Takaishi et al., 1993(Takaishi et al., , 1994. The mode of action of Rho in cell sca...

Hepatocyte Growth Factor-induced Ras Activation Requires ERM Proteins Linked to Both CD44v6 and F-Actin

“…18, January 2007the activation of receptor binding signaling components in response to HGF but is needed to activate Ras, most likely via the recruitment of Ras into a complex with Sos (or a Shp-2-regulated GEF; Kodama et al, 2000). In agreement with this assumption, ezrin could be coimmunoprecipitated with Sos upon HGF stimulation in 293 cells ( Figure 3D).…”

Inhibition of SHP2 leads to mesenchymal to epithelial transition in breast cancer cells

“…These results are consistent with previous reports that showed that SHP2 plays a positive role in fibroblast motility and migration. [23][24][25][26] Thus, interference with SHP2 function might provide a means to inhibit cancer cell metastasis. Unexpectedly, we discovered that EGF can induce translocation of b-catenin to the nucleus in SHP2-dependent manner.…”

“…Previous work has shown that SHP2 suppresses cell adhesion and enhances motility. [23][24][25][26] We sough to investigate the significance of SHP2 inhibition on breast cancer cells motility and scattering. Initially, this possibility was tested by the monolayer wound-healing assay.…”

Specific inhibitors of the protein tyrosine phosphatase Shp2 identified by high-throughput docking

“…Induction of scattering (37,38) and branching morphogenesis (39) of MDCK epithelial cells by the growth factor HGF/SF have been shown to depend on Shp2 (18,30). Stimulation of MDCK epithelial cells grown on cell culture dishes with HGF/SF results in loss of cell-cell contacts, increased cell motility, and conversion from an epithelial to a fibroblast-like appearance (Fig.…”