Plasmodium falciparum phospholipase C hydrolyzing sphingomyelin and lysocholinephospholipids is a possible target for malaria chemotherapy.
Sphingomyelinase (SMase) is one of the principal enzymes in sphingomyelin (SM) metabolism. Here, we identified a Plasmodium falciparum gene (PfNSM) encoding a 46-kD protein, the amino acid sequence of which is approximately 25% identical to that of bacteria SMases. Biochemical analyses of the recombinant protein GST-PfNSM, a fusion protein of the PfNSM product with glutathione-S-transferase, reveal that this enzyme retained similar characteristics in various aspects to SMase detected in P. falciparum-infected erythrocytes and isolated parasites. In addition, the recombinant protein retains hydrolyzing activity not only of SM but also of lysocholinephospholipids (LCPL) including lysophosphatidylcholine and lysoplatelet-activating factor, indicating that PfNSM encodes SM/LCPL-phospholipase C (PLC). Scyphostatin inhibited SM/LCPL-PLC activities of the PfNSM product as well as the intraerythrocytic proliferation of P. falciparum in a dose-dependent manner with ID(50) values for SM/LCPL-PLC activities and the parasite growth at 3-5 microM and approximately 7 microM, respectively. Morphological analysis demonstrated most severe impairment in the intraerythrocytic development with the addition of scyphostatin at trophozoite stage than at ring or schizont stages, suggesting its effect specifically on the stage progression from trophozoite to schizont, coinciding with the active transcription of PfNSM gene.
Hanada
Kentaro
K
Department of Biochemistry and Cell Biology, Japan Science and Technology Corporation, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan. hanak@nih.go.jp
Palacpac
Nirianne Marie Q
NM
Magistrado
Pamela A
PA
Kurokawa
Ken
K
Rai
Ganesh
G
Sakata
Daiji
D
Hara
Tomoko
T
Horii
Toshihiro
T
Nishijima
Masahiro
M
Mitamura
Toshihide
T
D000577:Amides / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D017125:Genes, Protozoan; D008244:Lysophosphatidylcholines / Q000378:metabolism; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000201:enzymology* / Q000235:genetics; D010972:Platelet Activating Factor / Q000031:analogs & derivatives* / Q000378:metabolism; D011753:Pyrones / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013109:Sphingomyelins / Q000378:metabolism; D013379:Substrate Specificity; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D000577:Amides; D008244:Lysophosphatidylcholines; C029271:O-deacetyl platelet activating factor; D010972:Platelet Activating Factor; D011753:Pyrones; D011994:Recombinant Proteins; D013109:Sphingomyelins; C121123:scyphostatin; D010738:Type C Phospholipases; D013108:Sphingomyelin Phosphodiesterase