Involvement of phospholipase D in AP-1 activation
Field:	Neurotransmitters and receptors
Authors:	Fried, Ulrik Moller, Kristian Alling, Christer
Address of presenting author:	Dept. Medical Neurochemistry Lund University Hospital 221 85 Lund Sweden
E-mail:	ulrik.fried@neurokemi.lu.se
Phone:	0046-46-175375
Fax:	0046-46-149870
Text of abstract:	Aim The aim of this study was to investigate the role of phospholipase D (PLD) in activation of transcription factor Activator Protein-1 (AP-1) in neuronal cells. PLD hydrolyzes phosphatidylcholine to generate phosphatidic acid and choline and the enzyme have been implicated in several cellular processes. PA is further processed to generate diacylglycerol which is an activator of protein kinase C (PKC) and stimulation of this enzyme leads to AP-1 activation. This is the hypothesised pathway connecting PLD to AP-1 activation. Method Human neuroblastoma cells were co-transfected with an AP-1 regulated reporter gene plasmid and a human PLD1 expressing plasmid (in controls this plasmid was exchanged to a similar plasmid not expressing PLD). Cells were stimulated with different agonists that activate PLD and reporter gene activity was measured. Results Preliminary results indicate that both receptor stimulated and direct PKC stimulated AP-1 activity are enhanced several times in cells overexpressing PLD. Inhibition of the enzymatic step that generates diacylglycerol from PA (by propranolol) showed that this step was at least in part necessary to give the observed PLD dependent AP-1 activation. Conclusions These results provides an interesting initial step to further study the possible involvement of PLD as a mediator of gene expression in neuronal cells. Whether the endogenous PLD enzymes are involved in AP-1 activation and what possible consequences this could have on cell function need to be addressed.
Keywords:	Phospholipase D, Activator Protein-1, gene regulation, nerve cells

Created 2000-04-12