title: Phosphorylation of phospholipase D1 and the modulation of its interaction with RhoA by cAMP-dependent protein kinase.
abstract: Agents that elevate cellular cAMP are known to inhibit the activation of phospholipase D (PLD). We investigated whether PLD can be phosphorylated by cAMP-dependent protein kinase (PKA) and PKA-mediated phosphorylation affects the interaction between PLD and RhoA, a membrane regulator of PLD. PLD1, but not PLD2 was found to be phosphorylated in vivo by the treatment of dibutyryl cAMP (dbcAMP) and in vitro by PKA. PKA inhibitor (KT5720) abolished the dbcAMP-induced phosphorylation of PLD1, but dibutyryl cGMP (dbcGMP) failed to phosphorylate PLD1. The association between PLD1 and Val14RhoA in an immunoprecipitation assay was abolished by both dbcAMP and dbcGMP. Moreover, RhoA but not PLD1 was dissociated from the membrane to the cytosolic fraction in dbcAMP-treated cells. These results suggest that both PLD1 and RhoA are phosphorylated by PKA and the interaction between PLD1 and RhoA is inhibited by the phosphorylation of RhoA rather than by the phosphorylation of PLD1.
authors.affiliation: Medical Research Center for Cancer Molecular Therapy and Department of Biochemistry, College of Medicine, Dong-A University, Busan 602-714, Korea.
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Jang
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Lee
authors.forename: Hae-Young
authors.initials: HY
authors.lastname: Park
authors.forename: Yoe-Sik
authors.initials: YS
authors.lastname: Bae
authors.forename: Do Sik
authors.initials: DS
authors.lastname: Min
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Ryu
authors.forename: Jong-Young
authors.initials: JY
authors.lastname: Kwak
mesh_terms: D003994:Bucladesine / Q000494:pharmacology; D002227:Carbazoles / Q000494:pharmacology; D045744:Cell Line, Tumor; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003995:Dibutyryl Cyclic GMP / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D010739:Phospholipase D / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011758:Pyrroles / Q000494:pharmacology; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D002227:Carbazoles; D004791:Enzyme Inhibitors; D007211:Indoles; D011758:Pyrroles; D003995:Dibutyryl Cyclic GMP; C057416:KT 5720; D003994:Bucladesine; D017868:Cyclic AMP-Dependent Protein Kinases; D010739:Phospholipase D; D020742:rhoA GTP-Binding Protein