Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis
Malaria parasites have evolved unusual metabolic adaptations that specialize them for growth within heme-rich human erythrocytes. During blood-stage infection, Plasmodium falciparum parasites internalize and digest abundant host hemoglobin within the digestive vacuole. This massive catabolic process...
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eLife Sciences Publications Ltd
2024-12-01
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| Online Access: | https://elifesciences.org/articles/100256 |
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| author | Amanda Mixon Blackwell Yasaman Jami-Alahmadi Armiyaw S Nasamu Shota Kudo Akinobu Senoo Celine Slam Kouhei Tsumoto James A Wohlschlegel Jose Manuel Martinez Caaveiro Daniel E Goldberg Paul A Sigala |
| author_facet | Amanda Mixon Blackwell Yasaman Jami-Alahmadi Armiyaw S Nasamu Shota Kudo Akinobu Senoo Celine Slam Kouhei Tsumoto James A Wohlschlegel Jose Manuel Martinez Caaveiro Daniel E Goldberg Paul A Sigala |
| author_sort | Amanda Mixon Blackwell |
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| description | Malaria parasites have evolved unusual metabolic adaptations that specialize them for growth within heme-rich human erythrocytes. During blood-stage infection, Plasmodium falciparum parasites internalize and digest abundant host hemoglobin within the digestive vacuole. This massive catabolic process generates copious free heme, most of which is biomineralized into inert hemozoin. Parasites also express a divergent heme oxygenase (HO)-like protein (PfHO) that lacks key active-site residues and has lost canonical HO activity. The cellular role of this unusual protein that underpins its retention by parasites has been unknown. To unravel PfHO function, we first determined a 2.8 Å-resolution X-ray structure that revealed a highly α-helical fold indicative of distant HO homology. Localization studies unveiled PfHO targeting to the apicoplast organelle, where it is imported and undergoes N-terminal processing but retains most of the electropositive transit peptide. We observed that conditional knockdown of PfHO was lethal to parasites, which died from defective apicoplast biogenesis and impaired isoprenoid-precursor synthesis. Complementation and molecular-interaction studies revealed an essential role for the electropositive N-terminus of PfHO, which selectively associates with the apicoplast genome and enzymes involved in nucleic acid metabolism and gene expression. PfHO knockdown resulted in a specific deficiency in levels of apicoplast-encoded RNA but not DNA. These studies reveal an essential function for PfHO in apicoplast maintenance and suggest that Plasmodium repurposed the conserved HO scaffold from its canonical heme-degrading function in the ancestral chloroplast to fulfill a critical adaptive role in organelle gene expression. |
| format | Article |
| id | doaj-art-d89d6801f7f54b70a5e0d7f99a20f921 |
| institution | Kabale University |
| issn | 2050-084X |
| language | English |
| publishDate | 2024-12-01 |
| publisher | eLife Sciences Publications Ltd |
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| series | eLife |
| spelling | doaj-art-d89d6801f7f54b70a5e0d7f99a20f9212024-12-11T13:11:47ZengeLife Sciences Publications LtdeLife2050-084X2024-12-011310.7554/eLife.100256Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesisAmanda Mixon Blackwell0https://orcid.org/0000-0002-7473-5822Yasaman Jami-Alahmadi1https://orcid.org/0000-0001-8289-2222Armiyaw S Nasamu2Shota Kudo3Akinobu Senoo4Celine Slam5Kouhei Tsumoto6James A Wohlschlegel7Jose Manuel Martinez Caaveiro8Daniel E Goldberg9https://orcid.org/0000-0003-3529-8399Paul A Sigala10https://orcid.org/0000-0002-3464-3042Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United StatesDepartment of Biological Chemistry, University of California, Los Angeles, Los Angeles, United StatesDepartments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, United StatesDepartment of Chemistry & Biotechnology, The University of Tokyo, Tokyo, JapanDepartment of Protein Drug Discovery, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, JapanDepartment of Biochemistry, University of Utah School of Medicine, Salt Lake City, United StatesDepartment of Chemistry & Biotechnology, The University of Tokyo, Tokyo, Japan; Department of Bioengineering, University of Tokyo, Tokyo, JapanDepartment of Biological Chemistry, University of California, Los Angeles, Los Angeles, United StatesDepartment of Chemistry & Biotechnology, The University of Tokyo, Tokyo, JapanDepartments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, United StatesDepartment of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States; Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, United StatesMalaria parasites have evolved unusual metabolic adaptations that specialize them for growth within heme-rich human erythrocytes. During blood-stage infection, Plasmodium falciparum parasites internalize and digest abundant host hemoglobin within the digestive vacuole. This massive catabolic process generates copious free heme, most of which is biomineralized into inert hemozoin. Parasites also express a divergent heme oxygenase (HO)-like protein (PfHO) that lacks key active-site residues and has lost canonical HO activity. The cellular role of this unusual protein that underpins its retention by parasites has been unknown. To unravel PfHO function, we first determined a 2.8 Å-resolution X-ray structure that revealed a highly α-helical fold indicative of distant HO homology. Localization studies unveiled PfHO targeting to the apicoplast organelle, where it is imported and undergoes N-terminal processing but retains most of the electropositive transit peptide. We observed that conditional knockdown of PfHO was lethal to parasites, which died from defective apicoplast biogenesis and impaired isoprenoid-precursor synthesis. Complementation and molecular-interaction studies revealed an essential role for the electropositive N-terminus of PfHO, which selectively associates with the apicoplast genome and enzymes involved in nucleic acid metabolism and gene expression. PfHO knockdown resulted in a specific deficiency in levels of apicoplast-encoded RNA but not DNA. These studies reveal an essential function for PfHO in apicoplast maintenance and suggest that Plasmodium repurposed the conserved HO scaffold from its canonical heme-degrading function in the ancestral chloroplast to fulfill a critical adaptive role in organelle gene expression.https://elifesciences.org/articles/100256malariaapicoplastheme oxygenasegene expressionRNA |
| spellingShingle | Amanda Mixon Blackwell Yasaman Jami-Alahmadi Armiyaw S Nasamu Shota Kudo Akinobu Senoo Celine Slam Kouhei Tsumoto James A Wohlschlegel Jose Manuel Martinez Caaveiro Daniel E Goldberg Paul A Sigala Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis eLife malaria apicoplast heme oxygenase gene expression RNA |
| title | Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis |
| title_full | Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis |
| title_fullStr | Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis |
| title_full_unstemmed | Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis |
| title_short | Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis |
| title_sort | malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis |
| topic | malaria apicoplast heme oxygenase gene expression RNA |
| url | https://elifesciences.org/articles/100256 |
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