Hepatocyte growth factor (Hgf) stimulates low density lipoprotein receptor-related protein (Lrp) 5/6 phosphorylation and promotes canonical Wnt signaling [Molecular Bases of Disease]

April 1st, 2014 by Koraishy, F. M., Silva, C., Mason, S., Wu, D., Cantley, L. G.

While Wnt and Hgf signaling pathways are known to regulate epithelial cell responses during injury and repair, whether they exhibit functional cross-talk is not well defined. Canonical Wnt signaling is initiated by the phosphorylation of the Lrp5/6 co-receptors. In the current study we demonstrate that Hgf stimulates the Met-dependent and Wnt-independent phosphorylation of Lrp5/6 at 3 separate activation motifs in subconfluent, de-differentiated renal epithelial cells. Hgf treatment stimulates the selective association of active Gsk3 with Lrp5/6, resulting in Lrp5/6 phosphorylation. In contrast, Akt-phosphorylated inactive Gsk3 is excluded from this association. Hgf stimulates β-catenin stabilization and nuclear accumulation and protects against epithelial cell apoptosis in an Lrp5/6 dependent fashion. In vivo, the increase in Lrp5/6 phosphorylation and β-catenin stabilization in the first 6-24 hours after renal ischemic injury was significantly reduced in mice lacking Met receptor in the renal proximal tubule. Our results thus identify Hgf as an important transactivator of canonical Wnt signaling that is mediated by Met-stimulated, Gsk3-dependent Lrp5/6 phosphorylation.
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