Protein kinase C-dependent regulation of human erythroleukemia (HEL) cell sphingosine kinase activity

• Published in: Biochimica et biophysica acta Vol. 1303; no. 3; pp. 233 - 242
• Main Authors: Buehrer, Benjamin M, Bardes, Elaine S, Bell, Robert M
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 18-10-1996
• Subjects: Cell Differentiation - drug effects; Cellular differentiation; Dimethyl Sulfoxide - pharmacology; Enzyme Activation - drug effects; Enzyme Inhibitors - pharmacology; Human erythroleukemia cell; Humans; Kinetics; Leukemia, Erythroblastic, Acute - enzymology; Naphthalenes - pharmacology; Phorbol ester; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Protein kinase C; Protein Kinase C - antagonists & inhibitors; Protein Kinase C - metabolism; Sphingosine kinase; Staurosporine - pharmacology; Tetradecanoylphorbol Acetate - pharmacology; Tumor Cells, Cultured; Sphingosine kinase; Protein kinase C; PDBu; PMA; DMSO; Phorbol ester; PDGF; Human erythroleukemia cell; PKC; Cellular differentiation; HEL
• ISSN: 0005-2760; 0006-3002; 1879-145X
• DOI: 10.1016/0005-2760(96)00092-6

Sphingosine kinase functions in both the catabolism of sphingosine and in signal transduction pathways utilizing sphingosine-1-phosphate. The regulation of sphingosine kinase activity in human erythroleukemia (HEL) cells was investigated by treatment with several bioactive agents. Treatment of HEL cells with phorbol 12-myristate 13-acetate (PMA) caused a time- and concentration-dependent increase in sphingosine kinase activity measured in vitro. Sphingosine kinase activity increased in a phorbol ester- and diacylglycerolspecific manner. Staurosporine and calphostin C, protein kinase C (PKC) inhibitors, blocked the increase in sphingosine kinase activity, suggesting a PKC-dependent regulation. The effects of PMA on sphingosine kinase were dependent on transcription and translation. Purified PKC had no direct effect on sphingosine kinase activity. However, these studies led to the observation that HEL cell sphingosine kinase activity is stimulated in vitro by phosphatidylserine. Interestingly, other inducers of HEL cell differentiation, dimethylsulfoxide and retinoic acid, did not affect sphingosine kinase activity. These results indicate a separate and distinct pathway of PKC-dependent sphingosine kinase activation, and suggest a role for sphingosine kinase in regulation of cell function.