title: Susceptibility of Plasmodium falciparum cyclic AMP-dependent protein kinase and its mammalian homologue to the inhibitors.
abstract: Cyclic AMP-dependent protein kinase (protein kinase A, PKA) is a key element in many cell signaling pathways. An essential role of Plasmodium falciparum PKA (PfPKA) activity was reported in the intraerythrocytic growth of the malaria parasite. However, molecular characterization of PfPKA using purified recombinant proteins has not yet been performed. Here, we report the first successful purification of the enzymatically active PKA catalytic subunit of P. falciparum (PfPKA-C) using a wheat germ cell-free expression system. Interestingly, parasite enzymatic activity was weakly inhibited as compared with the inhibition of mammalian PKA catalytic subunit (PKA-C) by the specific PKA inhibitor, H89. Furthermore, PfPKA-C was only slightly inhibited by protein kinase inhibitor (PKI). These results suggest that substrate sites of PfPKA-C may be different from those of mammalian PKA-Cs. In addition, potential PKI corresponding to malarial PKA-C would also be different from those of mammalian cells.
authors.affiliation: Department of Veterinary Microbiology, Faculty of Agriculture, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sudo
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kato
authors.forename: Kyousuke
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Yukinobu
authors.initials: Y
authors.lastname: Tohya
authors.forename: Hiroomi
authors.initials: H
authors.lastname: Akashi
mesh_terms: D000818:Animals; D002417:Cattle; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000302:isolation & purification*; D007546:Isoquinolines / Q000494:pharmacology*; D010963:Plasmodium falciparum / Q000201:enzymology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D015800:Protozoan Proteins / Q000037:antagonists & inhibitors* / Q000302:isolation & purification*; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification; D013449:Sulfonamides / Q000494:pharmacology*
chemical_list: D007546:Isoquinolines; D047428:Protein Kinase Inhibitors; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D013449:Sulfonamides; D017868:Cyclic AMP-Dependent Protein Kinases; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide