Cu,Zn superoxide dismutase increases intracellular calcium levels via a phospholipase C-protein kinase C pathway in SK-N-BE neuroblastoma cells.
The superoxide dismutase isoenzymes (SOD) play a key role in scavenging, O*2- radicals. In contrast with previous studies, recent data have shown that human neuroblastoma cells are able to export the cytosolic Cu,Zn superoxide dismutase (SOD1), thus suggesting a paracrine role exerted by this enzyme in the nervous system. To evaluate whether SOD1 could activate intracellular signalling pathways, the functional interaction between SOD1 and human neuroblastoma SK-N-BE cells was investigated. By analyzing the surface binding of biotinylated SOD1 on SK-N-BE cells and by measuring intracellular calcium concentrations and PKC activity, we demonstrated that SOD1 specifically interacts in a dose-dependent manner with the cell surface membrane of SK-N-BE. This binding was able to activate a PLC-PKC-dependent pathway that increased intracellular calcium concentrations mainly deriving from the intracellular stores. Furthermore, we showed that this effect was independent of SOD1 dismutase activity and was totally inhibited by U73122, the PLC blocker. On the whole, these data indicate that SOD1 carries out a neuromodulatory role affecting calcium-dependent cellular functions.
Mondola
Paolo
P
Division of Physiology, Department of Neuroscience, School of Medicine, University of Naples Federico II, Via S. Pansini, 5, 80131 Naples, Italy. mondola@unina.it
Santillo
Mariarosaria
M
Serù
Rosalba
R
Damiano
Simona
S
Alvino
Claudio
C
Ruggiero
Giuseppina
G
Formisano
Pietro
P
Terrazzano
Giuseppe
G
Secondo
Agnese
A
Annunziato
Lucio
L
D000975:Antioxidants / Q000378:metabolism; D019921:Biotinylation; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism*; D011760:Pyrrolidinones / Q000494:pharmacology; D017382:Reactive Oxygen Species; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000737:chemistry*; D013997:Time Factors; D010738:Type C Phospholipases / Q000378:metabolism*
D000975:Antioxidants; D004791:Enzyme Inhibitors; D004963:Estrenes; D011760:Pyrrolidinones; D017382:Reactive Oxygen Species; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D013482:Superoxide Dismutase; D011493:Protein Kinase C; D010738:Type C Phospholipases; D002118:Calcium