In:
PLOS Pathogens, Public Library of Science (PLoS), Vol. 19, No. 8 ( 2023-8-31), p. e1011566-
Abstract:
As an obligate intracellular parasite, Toxoplasma gondii must import essential nutrients from the host cell into the parasitophorous vacuole. We previously reported that the parasite scavenges cholesterol from host endocytic organelles for incorporation into membranes and storage as cholesteryl esters in lipid droplets. In this study, we have investigated whether Toxoplasma utilizes cholesterol as a precursor for the synthesis of metabolites, such as steroids. In mammalian cells, steroidogenesis occurs in mitochondria and involves membrane-bound type I cytochrome P450 oxidases that are activated through interaction with heme-binding proteins containing a cytochrome b5 domain, such as members of the membrane-associated progesterone receptor (MAPR) family. Our LC-MS targeted lipidomics detect selective classes of hormone steroids in Toxoplasma , with a predominance for anti-inflammatory hydroxypregnenolone species, deoxycorticosterone and dehydroepiandrosterone. The genome of Toxoplasma contains homologs encoding a single type I CYP450 enzyme (we named TgCYP450mt) and a single MAPR (we named TgMAPR). We showed that TgMAPR is a hemoprotein with conserved residues in a heme-binding cytochrome b5 domain. Both TgCYP450 and TgMAPR localize to the mitochondrion and show interactions in in situ proximity ligation assays. Genetic ablation of cyp450mt is not tolerated by Toxoplasma ; we therefore engineered a conditional knockout strain and showed that iΔTgCYP450mt parasites exhibit growth impairment in cultured cells. Parasite strains deficient for mapr could be generated; however, ΔTgMAPR parasites suffer from poor global fitness, loss of plasma membrane integrity, aberrant mitochondrial cristae, and an abnormally long S-phase in their cell cycle. Compared to wild-type parasites, iΔTgCYP450mt and ΔTgMAPR lost virulence in mice and metabolomics studies reveal that both mutants have reduced levels of steroids. These observations point to a steroidogenic pathway operational in the mitochondrion of a protozoan that involves an evolutionary conserved TgCYP450mt enzyme and its binding partner TgMAPR.
Type of Medium:
Online Resource
ISSN:
1553-7374
DOI:
10.1371/journal.ppat.1011566
DOI:
10.1371/journal.ppat.1011566.g001
DOI:
10.1371/journal.ppat.1011566.g002
DOI:
10.1371/journal.ppat.1011566.g003
DOI:
10.1371/journal.ppat.1011566.g004
DOI:
10.1371/journal.ppat.1011566.g005
DOI:
10.1371/journal.ppat.1011566.g006
DOI:
10.1371/journal.ppat.1011566.g007
DOI:
10.1371/journal.ppat.1011566.g008
DOI:
10.1371/journal.ppat.1011566.g009
DOI:
10.1371/journal.ppat.1011566.t001
DOI:
10.1371/journal.ppat.1011566.s001
DOI:
10.1371/journal.ppat.1011566.s002
DOI:
10.1371/journal.ppat.1011566.s003
DOI:
10.1371/journal.ppat.1011566.s004
DOI:
10.1371/journal.ppat.1011566.s005
DOI:
10.1371/journal.ppat.1011566.s006
DOI:
10.1371/journal.ppat.1011566.s007
DOI:
10.1371/journal.ppat.1011566.s008
DOI:
10.1371/journal.ppat.1011566.s009
DOI:
10.1371/journal.ppat.1011566.s010
DOI:
10.1371/journal.ppat.1011566.s011
DOI:
10.1371/journal.ppat.1011566.s012
DOI:
10.1371/journal.ppat.1011566.s013
DOI:
10.1371/journal.ppat.1011566.s014
DOI:
10.1371/journal.ppat.1011566.r001
DOI:
10.1371/journal.ppat.1011566.r002
DOI:
10.1371/journal.ppat.1011566.r003
DOI:
10.1371/journal.ppat.1011566.r004
DOI:
10.1371/journal.ppat.1011566.r005
DOI:
10.1371/journal.ppat.1011566.r006
Language:
English
Publisher:
Public Library of Science (PLoS)
Publication Date:
2023
detail.hit.zdb_id:
2205412-1
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