Differential Transactivation of Sphingosine-1-Phosphate Receptors Modulates NGF-Induced Neurite Extension

• Published in: The Journal of cell biology Vol. 166; no. 3; pp. 381 - 392
• Main Authors: Toman, Rachelle E., Payne, Shawn G., Watterson, Kenneth R., Maceyka, Michael, Lee, Norman H., Milstien, Sheldon, Bigbee, John W., Spiegel, Sarah
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 02.08.2004; The Rockefeller University Press
• Subjects: Animals; Antibodies; Cell membranes; Cells; Cellular biology; Enzymes; Ganglia, Spinal - metabolism; Microscopy; Nerve Growth Factor - metabolism; Nerves; Neurites; Neurites - metabolism; Neurons; PC12 Cells; Phosphates; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Proteins; rac GTP-Binding Proteins - metabolism; Rats; Receptors; Receptors, G-Protein-Coupled - genetics; Receptors, G-Protein-Coupled - metabolism; Receptors, Lysophospholipid; rho GTP-Binding Proteins - metabolism; Transactivation; Transcriptional Activation
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200402016

The process of neurite extension after activation of the TrkA tyrosine kinase receptor by nerve growth factor (NGF) involves complex signaling pathways. Stimulation of sphingosine kinase 1 (SphK1), the enzyme that phosphorylates sphingosine to form sphingosine-1-phosphate (S1P), is part of the functional TrkA signaling repertoire. In this paper, we report that in PC12 cells and dorsal root ganglion neurons, NGF translocates SphK1 to the plasma membrane and differentially activates the S1P receptors S1 P1and S1 P2in a SphK1-dependent manner, as determined with specific inhibitors and small interfering RNA targeted to SphK1. NGF-induced neurite extension was suppressed by down-regulation of S1 P1expression with antisense RNA. Conversely, when overexpressed in PC12 cells, transactivation of S1 P1by NGF markedly enhanced neurite extension and stimulation of the small GTPase Rac, important for the cytoskeletal changes required for neurite extension. Concomitantly, differentiation down-regulated expression of S1 P2whose activation would stimulate Rho and inhibit neurite extension. Thus, differential transactivation of S1P receptors by NGF regulates antagonistic signaling pathways that modulate neurite extension.