Determinants of apicoplast maintenance in malaria parasites

Malaria parasites contain a plastid organelle called the apicoplast that is required for parasite survival in humans and for transmission to mosquitoes. The apicoplast has long been recognized as an important source of new drug targets to combat the inevitable problem of drug resistance, however, it has proven difficult to identify and validate apicoplast proteins that are essential for parasite survival. This goal is now achievable using new genetic tools in combination with metabolic bypass of the apicoplast. Blood stage parasites treated with the isoprenoid precursor IPP (isopentenyl pyrophosphate) survive apicoplast inhibitors - even those which result in disruption of the organelle and loss of the organellar genome. We built on this finding by creating a metabolic bypass parasite line that produces isoprenoid precursors in the cytosol using an engineered four- enzyme mevalonate pathway. We propose to use a combination of genetic approaches in conjunction with metabolic bypass to identify all nuclear-encoded proteins which are essential for apicoplast function and parasite survival. We will also use new conditional tools (knockdown, conditional localization, DiCre) to further characterize the roles of specific proteins and the phenotypes associated with their loss. Our experiments will help to build a more complete picture of the metabolic pathways and non-metabolic processes required for apicoplast function and parasite survival. Ultimately, we intend to identify novel targets and to validate known targets for future development of drugs to cure malaria and stop its transmission.