Plasmodium falciparum is the deadliest species of malaria parasite that kills approximately 440,000 people every year. Artemisinin is the frontline antimalarial drug recommended by the WHO and makes a crucial contribution to global malaria control. Thus, emergent artemisinin-resistant strains of falciparum malaria pose a serious health threat. Partial artemisinin resistance manifests as a 24-48 h delay in parasite clearance, which allows the parasite time to further mutate and puts pressure on the partner drugs administered to protect artemisinin. Observed resistance mutations are often found in a protein called Kelch 13 (PfK13). This protein is localised to a ring at the neck of the parasite cytostome, a membrane invagination the parasite uses to engulf the cytoplasmic contents of host red blood cells. By-products of haemoglobin digestion are required to activate artemisinin so, in healthy parasites, feeding directly activates the drug that will kill them. In PfK13-mutants normal parasite feeding is diminished and the artemisinin-based cell death is delayed. In a related parasite, Toxoplasma gondii, TgK13 associates with a Dynamin-like protein (TgDrpC) that may mediate cytostome formation and we hypothesise that the same is true of P. falciparum. Using an inducible knockdown, we have shown that P. falciparum parasites die without the orthologous dynamin-like protein PfDYN3, and that PfDYN3 forms puncta at the parasite periphery that resemble PfK13 puncta. We are now in the process of co-transfecting a GFP-PfK13 parasite line with a haemagglutinin (HA)-tagged PfDYN3. This will be used to assess the relative localisation of PfK13 and PfDYN3. These experiments will interrogate whether PfDYN3 is involved in the PfK13-mediated parasite feeding process that is central to both parasite growth and artemisinin resistance.