Nuclear calcium controls the apoptotic-like cell death induced by d-erythro-sphinganine in tobacco cells.
Studies performed in animals have highlighted the major role of sphingolipids in regulating the balance between cell proliferation and cell death. Sphingolipids have also been shown to induce cell death in plants via calcium-based signalling pathways but the contribution of free cytosolic and/or nuclear calcium in the overall process has never been evaluated. Here, we show that increase in tobacco BY-2 cells of the endogenous content of Long Chain Bases (LCBs) caused by external application of d-erythro-sphinganine (DHS) is followed by immediate dose-dependent elevations of cellular free calcium concentration within the first minute in the cytosol and 10min later in the nucleus. Cells challenged with DHS enter a death process through apoptotic-like mechanisms. Lanthanum chloride, a general blocker of calcium entry, suppresses the cellular calcium variations and the PCD induced by DHS. Interestingly, dl-2-amino-5-phosphopentanoic acid (AP5) and [(+)-dizocilpine] (MK801), two inhibitors of animal and plant ionotropic glutamate receptors, suppress DHS-induced cell death symptoms by selectively inhibiting the variations of nuclear calcium concentration. The selective action of these compounds demonstrates the crucial role of nuclear calcium signature in controlling DHS-induced cell death in tobacco cells.
Lachaud
Christophe
C
Université de Toulouse, UPS, UMR CNRS-UPS, Surfaces Cellulaires et Signalisation chez les Végétaux, Auzeville, Castanet-Tolosan, France.
Da Silva
Daniel
D
Cotelle
Valérie
V
Thuleau
Patrice
P
Xiong
Tou Cheu
TC
Jauneau
Alain
A
Brière
Christian
C
Graziana
Annick
A
Bellec
Yannick
Y
Faure
Jean-Denis
JD
Ranjeva
Raoul
R
Mazars
Christian
C
D021581:Active Transport, Cell Nucleus; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D006868:Hydrolysis / Q000187:drug effects; D007811:Lanthanum / Q000494:pharmacology; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D051102:Serine C-Palmitoyltransferase / Q000096:biosynthesis / Q000235:genetics; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D014026:Nicotiana; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
D016194:Receptors, N-Methyl-D-Aspartate; C028521:lanthanum chloride; D007811:Lanthanum; D016291:Dizocilpine Maleate; C056639:2-amino-5-phosphopentanoic acid; D051102:Serine C-Palmitoyltransferase; D017853:Phosphotransferases (Alcohol Group Acceptor); C426837:sphingolipid long-chain base kinase; D014633:Valine; D013110:Sphingosine; C005682:safingol; D002118:Calcium