title: Propranolol increases phosphatidic acid level via activation of phospholipase D.
abstract: OBJECTIVE
  To investigate the propranolol-induced phospholipase D (PLD) activity, its contribution to the increase in the level of phosphatidic acid, and the role of protein kinase C (PKC) in this event.
  
  
  METHODS
  A combination of [3H]-myristate labeling, transphosphatidylation reaction, lipid extraction, and thin layer chromatography was used to measure the PLD activity. PKC inhibitors and prolonged phorbol-12-myristate-13-acetate (PMA) treatment were used to study the involvement of PKC in propranolol-induced PLD activation. Immunoblotting was used to detect the intracellular levels of PKC.
  
  
  RESULTS
  Treatment of A-549 cells with propranolol in the presence of butanol, resulted in the rapid activation of PLD. Propranolol induced the formation of phosphatidylbutanol (PBut), a unique product of PLD, at the expense of phosphatidic acid (PA) formation. Pretreatment of cells with PKC inhibitors Ro-31-8220, staurosporine, and rottlerin increased the propranolol-induced PLD. Down-regulation of PKC by prolonged treatment of cells with PMA also potentiated the propranolol-induced PLD activity.
  
  
  CONCLUSIONS
  Propranolol induces rapid activation of PLD activity, which results in the increase in intracellular level of PA. The data also indicate that propranolol-induced PLD activity could be negatively regulated by PKC.
authors.affiliation: State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: M Q
authors.initials: MQ
authors.lastname: Chai
authors.forename: J S
authors.initials: JS
authors.lastname: Chen
authors.forename: S
authors.initials: S
authors.lastname: Zhao
authors.forename: J G
authors.initials: JG
authors.lastname: Song
mesh_terms: D004789:Enzyme Activation; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology; D010712:Phosphatidic Acids / Q000378:metabolism*; D010739:Phospholipase D / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology*; D011493:Protein Kinase C / Q000502:physiology; D019311:Staurosporine / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D010712:Phosphatidic Acids; D011433:Propranolol; D011493:Protein Kinase C; D010739:Phospholipase D; D019311:Staurosporine