Characterizing a novel Plasmodium cytoskeletal protein

Abstract Plasmodium falciparum is a pathogenic eukaryote in the phylum Apicomplexa with a complex life cycle that alternates between Anopheles mosquitoes and humans. During the blood stages of the P. falciparum life cycle, a single merozoite invades a human red blood cell (RBC). Over the course of 48 hours, the parasite multiplies its genetic material and organelles via schizogony to form 20-36 merozoites. During infection, a small subset of these parasites (~0.2-1.0%) commit and differentiate into transmissible male and female gametocytes via staged process called gametocytogenesis. These two processes require elaborate, controlled cytoskeletal remodeling to occur. The Plasmodium cytoskeleton comprises the pellicle, which includes the parasite plasma membrane and a specialized organelle referred to as the inner membrane complex, and the subpellicular network that constitutes microtubules and a family of intermediate filament-like proteins called alveolins. These structures together serve to partition cytoplasmic contents during segmentation, confer cell shape and rigidity for daughter merozoites and developing gametocytes, and provide essential structure support during gliding motility and RBC invasion. We have recently discovered a novel Plasmodium cytoskeletal protein, PfFIG (Found In Gametocytes) during our study the basal complex during blood stage P. falciparum infection. My preliminary data demonstrate that PfFIG is important for asexual replication and is associated with microtubule dynamics in segmenting schizonts and maturing gametocytes. We do not know, however, the functional role of PfFIG during the Plasmodium blood stages of human malaria infection. Using inducible knockout (iKO) systems together with super-resolution and cell viability assays, I will characterize the role of PfFIG (PF3D7_1435600) in P. falciparum daughter cell segmentation and gametocyte maturation. This will elucidate its unique role in Plasmodium microtubule dynamics, specifically as it contributes to cell shape and facilitates life stage transitions. Additionally, I will perform immunoprecipitation and proximity-labeling experiments to map the PfFIG interactome, identifying proteins of interest for future study and characterization. This research will broaden our understandings of the core cellular machinery utilized by Plasmodium to carry out its unique life cycle. Specifically, study of Plasmodium-specific cytoskeletal proteins and their role across parasite life stages will bring us closer to targeting these proteins with antimalarial drugs.