Apicoplast

The **apicoplast** is a non-photosynthetic, plastid-like organelle found in most apicomplexan parasites, including *Plasmodium falciparum* (the cause of malaria) and *Toxoplasma gondii*. It evolved from a secondary endosymbiosis event involving a red alga and retains a four-membrane structure and several essential metabolic pathways, particularly for fatty acid, isoprenoid, and heme synthesis, all of which are distinct from mammalian pathways[1][4][6]. This organelle is critical for parasite survival, as disrupting its biogenesis or unique pathways leads to parasite death or loss of infectivity. The apicoplast’s prokaryotic ancestry and essential biosynthetic functions make it an attractive and validated drug target for treatment of malaria and related protozoan infections. However, it is not an individual molecular target, but rather a complex organelle comprising many molecules and pathways; thus, the entry "apicoplast" does not conform to typical molecular target conventions and is considered "incorrect" as a canonical drug target name[2][5][7]. **Note:** - The apicoplast is an organelle, not a single molecule, enzyme, transporter, or typical receptor. - All drug interactions are with proteins and pathways within the apicoplast, rather than the organelle itself. - If a more precise, druggable target is required, specify individual enzymes or pathways within the apicoplast, such as "1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR)" or type II fatty acid synthase (FAS II)[2][1][3].

Inhibition of apicoplast genome replication, transcription, or translation (e.g., by doxycycline and tetracycline) - Inhibition of isoprenoid precursor biosynthesis pathway (e.g., by fosmidomycin) - Disruption of fatty acid synthesis