Proliferin induces endothelial cell chemotaxis through a G protein-coupled, mitogen-activated protein kinase-dependent pathway - PubMed (original) (raw)

Proliferin induces endothelial cell chemotaxis through a G protein-coupled, mitogen-activated protein kinase-dependent pathway

J C Groskopf et al. Endocrinology. 1997 Jul.

Abstract

To investigate the mechanism of action of the placental angiogenic hormone proliferin (PLF), we analyzed the signaling components in endothelial cells that are required for PLF-induced chemotaxis. Pertussis toxin, which inactivates Gi proteins, inhibited PLF-induced chemotaxis of endothelial cells. Gi proteins can lead to activation of the mitogen-activated protein kinase (MAPK) pathway; PLF was found to stimulate MAPK activity, and this induction was blocked by both pertussis toxin and a specific inhibitor of MAPK kinase, PD 098059. Furthermore, a blockade of MAPK activation prevented endothelial cell movement in response to PLF. As PLF functionally interacts with the insulin-like growth factor II (IGF-II)/mannose 6-phosphate receptor, we also examined the effects of pertussis toxin and PD 098059 on another ligand for this receptor, a mutant form of IGF-II; both inhibitors also block the action of this factor on endothelial cells. These data suggest that chemotaxis initiated by PLF and mediated by the IGF-II/mannose 6-phosphate receptor occurs through a G protein-coupled pathway, and that MAPK activation is necessary for the chemotactic response.

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