Sphingolipid metabolites selectively elicit increases in nuclear calcium concentration in cell suspension cultures and in isolated nuclei of tobacco

• Published in: Cell calcium (Edinburgh) Vol. 43; no. 1; pp. 29 - 37
• Main Authors: Xiong, Tou Cheu, Coursol, Sylvie, Grat, Sabine, Ranjeva, Raoul, Mazars, Christian
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier India Pvt Ltd 01.01.2008; Elsevier
• Subjects: Advanced Basic Science; Aequorin; Calcium - metabolism; Calcium Signaling; Calcium signalling; Cell Fractionation; Cell Nucleus - enzymology; Cell Nucleus - metabolism; Cells, Cultured; Cellular Biology; Life Sciences; Nicotiana - cytology; Nicotiana - enzymology; Nicotiana - metabolism; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Plant cell nucleus; Sphingoid long-chain base; Sphingoid long-chain base kinase; Sphingolipids; Sphingolipids - chemistry; Sphingolipids - metabolism; Sphingolipids - pharmacology; Sphingosine - analogs & derivatives; Sphingosine - chemistry; Sphingosine - pharmacology; Tobacco BY-2 cells; Transient Receptor Potential Channels - antagonists & inhibitors; Calcium signalling; Tobacco BY-2 cells; Sphingolipids; Sphingoid long-chain base kinase; Aequorin; Sphingoid long-chain base; Plant cell nucleus; TRANSPORT DE CALCIUM; PLANT CELL NUCLEUS; TOBACCO BY-2 CELLS; TENEUR EN CALCIUM; SPHINGOID LONG-CHAIN BASE; AEQUORIN; CALCIUM SIGNALLING; SPHINGOLIPIDS; SPHINGOID LONG-CHAIN BASE KINASE
• ISSN: 0143-4160; 1532-1991
• DOI: 10.1016/j.ceca.2007.02.005

Abstract Sphingolipids are known to interfere with calcium-based signalling pathways. Here we report that these compounds modulate nuclear calcium signalling in tobacco BY-2 cells. Nuclear protein kinase activity phosphorylated endogenous sphingoid long-chain bases (LCBs), suggesting that LCBs are actively metabolized in the nucleus of tobacco BY-2 cells. The Δ4-unsaturated LCB d - erythro -sphingosine and the saturated LCB d - ribo -phytosphingosine elicited increases in free calcium in the nucleus in a dose-dependent and structure-related manner. However, neither sphingosine-1-phosphate nor C2-ceramide was able to stimulate nuclear calcium changes. N- , N -Dimethyl- d - erythro -sphingosine, a structural analogue of d - erythro -sphingosine, was the most efficient LCB so far tested in eliciting nuclear calcium changes both in intact tobacco BY-2 cells and in isolated nuclei. TRP channel inhibitors prevent the effect of DMS, suggesting that LCBs may activate TRP-like channels located on the inner nuclear membrane Collectively, the obtained data show that nuclei respond to LCBs on their own independently of the cytosolic compartment.