Delta24(25)-sterol methenyltransferase: intracellular localization and azasterol sensitivity in Leishmania major promastigotes overexpressing the enzyme.
Trypanosomatids contain predominantly ergostane-based sterols, which differ from cholesterol, the main sterol in mammalian cells, in the presence of a methyl group in the 24 position. The methylation is initiated by S-adenosyl-L-methionine:Delta(24 (25))-sterol methenyltransferase, an enzyme present in protozoa, but absent in mammals. The importance of this enzyme is underscored by its potential as a drug target in the treatment of the leishmaniases. Here, we report studies concerning the intracellular distribution of sterol methenyltransferase in Leishmania major promastigotes and overexpressing cells using a specific antibody raised against highly purified recombinant protein. It was found by immunofluorescence and electron microscopy studies that in L. major wild-type cells sterol methenyltransferase was primarily associated to the endoplasmic reticulum. In addition to this location, the protein was incorporated into translucent vesicles presumably of the endocytic pathway. We also found in this study that cells overproducing the enzyme do not have increased resistance to the sterol methenyltransferase inhibitor 22, 26 azasterol.
Jiménez-Jiménez
Carmen
C
Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, s/n 18100 Armilla, Granada, Spain.
Carrero-Lérida
Juana
J
Sealey-Cardona
Marco
M
Ruiz Pérez
Luis Miguel
LM
Urbina
Julio Alberto
JA
González Pacanowska
Dolores
D
D000818:Animals; D004083:Cholestanol / Q000031:analogs & derivatives* / Q000494:pharmacology; D004351:Drug Resistance; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004926:Escherichia coli / Q000201:enzymology; D018320:Leishmania major / Q000187:drug effects* / Q000201:enzymology* / Q000648:ultrastructure; D008780:Methyltransferases / Q000302:isolation & purification*; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D011994:Recombinant Proteins / Q000302:isolation & purification; D014162:Transfection; D022161:Transport Vesicles / Q000201:enzymology; D014344:Trypanocidal Agents / Q000494:pharmacology
C103731:22,26-azasterol; D011994:Recombinant Proteins; D014344:Trypanocidal Agents; D004083:Cholestanol; D008780:Methyltransferases; C022670:delta 24-sterol methyltransferase