The activation by agonists of phospholipase D (PLD) is a signal transduction pathway involved in toth vesicular trafficking and cell proliferation. In cultured astrocytes the highest PLD activation is elecited by endothelins (ETs), which also induce proliferation and this action has been correlated with the apperance of reactive gliosis after brain lessions. In our laboratory we have characterized the receptors mediating the effect of ETs and also shown that protein kinase C (PKC) is involved. In this project we propose to measure the actions of ETs in cultured astrocytes as an experimental model to study three aspects of PLD activation: 1- the mechanisms involved, including the identification of the PKC isoenzymes required, the study of the participation of the monomeric G proteins Arf and Rho and the expression analysis of the PLD isoenzymes; 2- the relationship between PLD and other signalling pathways also activated by ETs: phospholipases C and A\sub 2\nosub , phosphoinositide-3 kinase and mitogen activated protein kinase; 3- the role of PLD in cell proliferation, measuring the ability of growth factors to activate PLD and the effect of inhibiting the PLD catalyzed phosphatidate formation on DNA synthesis.
|Effective start/end date||1/10/98 → 1/10/01|