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The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs.

Strathprints serves world leading Open Access research by the University of Strathclyde, including research by the Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), where research centres such as the Industrial Biotechnology Innovation Centre (IBioIC), the Cancer Research UK Formulation Unit, SeaBioTech and the Centre for Biophotonics are based.

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Sphingosine prevents diacylglycerol signaling to mitogen-activated protein kinase in airway smooth muscle

Tolan, D and Conway, A M and Pyne, N J and Pyne, S (1997) Sphingosine prevents diacylglycerol signaling to mitogen-activated protein kinase in airway smooth muscle. American Journal of Physiology, 273 (3). C928-936. ISSN 0002-9513

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Abstract

Because many agonists utilize diacylglycerol (DAG) to initiate nuclear transcriptional activity via protein kinase C (PKC), we have investigated whether sphingosine might counter DAG. Sphingosine inhibited PKC activity in an isolated airway smooth muscle cell lysate and prevented the activation of mitogen-activated protein kinase (MAPK) by platelet-derived growth factor, bradykinin, and phorbol 12-myristate 13-acetate in intact cells. MAPK activation in response to all the agonists involves PKC. The stimulation of [3H]palmitate-labeled cells with sphingosine, in the presence of butan-1-ol (0.3%, vol/vol), induced an increase in [3H]phosphatidate (PtdOH) but was without effect on [3H]DAG. [3H]PtdOH synthesis was inhibited, whereas [3H]DAG levels were increased in the presence of the DAG kinase inhibitor R-59949, indicating that sphingosine stimulates phospholipase C/DAG kinase. Recycling of DAG from PtdOH was prevented by a sphingosine-dependent inhibition of PtdOH phosphohydrolase-2 activity. In conclusion, the sphingosine-induced conversion of DAG to PtdOH may serve to optimize the effect of sphingosine on MAPK. This may account for the antiproliferative action of sphingosine.