Mitochondrial localization of the mevalonate pathway enzyme 3-Hydroxy-3-methyl-glutaryl-CoA reductase in the Trypanosomatidae.
3-Hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) is a key enzyme in the sterol biosynthesis pathway, but its subcellular distribution in the Trypanosomatidae family is somewhat controversial. Trypanosoma cruzi and Leishmania HMGRs are closely related in their catalytic domains to bacterial and eukaryotic enzymes described but lack an amino-terminal domain responsible for the attachment to the endoplasmic reticulum. In the present study, digitonin-titration experiments together with immunoelectron microscopy were used to establish the intracellular localization of HMGR in these pathogens. Results obtained with wild-type cells and transfectants overexpressing the enzyme established that HMGR in both T. cruzi and Leishmania major is localized primarily in the mitochondrion and that elimination of the mitochondrial targeting sequence in Leishmania leads to protein accumulation in the cytosolic compartment. Furthermore, T. cruzi HMGR is efficiently targeted to the mitochondrion in yeast cells. Thus, when the gene encoding T. cruzi HMGR was expressed in a hmg1 hmg2 mutant of Saccharomyces cerevisiae, the mevalonate auxotrophy of mutant cells was relieved, and immunoelectron analysis showed that the parasite enzyme exhibits a mitochondrial localization, suggesting a conservation between the targeting signals of both organisms.
Peña-Diaz
Javier
J
Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas, 18001 Granada, Spain.
Montalvetti
Andrea
A
Flores
Carmen-Lisset
CL
Constán
Aurora
A
Hurtado-Guerrero
Ramon
R
De Souza
Wanderley
W
Gancedo
Carlos
C
Ruiz-Perez
Luis M
LM
Gonzalez-Pacanowska
Dolores
D
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004072:Digitonin / Q000737:chemistry; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism*; D007891:Leishmania / Q000201:enzymology / Q000648:ultrastructure; D008798:Mevalonic Acid / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000201:enzymology* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000378:metabolism / Q000648:ultrastructure; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000648:ultrastructure; D014351:Trypanosomatina / Q000201:enzymology* / Q000648:ultrastructure
D006903:Hydroxymethylglutaryl CoA Reductases; D004072:Digitonin; D008798:Mevalonic Acid