Structures of PI4KIIIβ complexes show simultaneous recruitment of Rab11 and its effectors

Phosphatidylinositol 4-kinases (PI4Ks) and small guanosine triphosphatases (GTPases) are essential for processes that require expansion and remodeling of phosphatidylinositol 4-phosphate (PI4P)-containing membranes, including cytokinesis, intracellular development of malarial pathogens, and replication of a wide range of RNA viruses. However, the structural basis for coordination of PI4K, GTPases, and their effectors is unknown. Here, we describe structures of PI4K beta (PI4KIII beta) bound to the small GTPase Rab11a without and with the Rab11 effector protein FIP3. The Rab11-PI4KIII beta interface is distinct compared with known structures of Rab complexes and does not involve switch regions used by GTPase effectors. Our data provide a mechanism for how PI4KIII beta coordinates Rab11 and its effectors on PI4P-enrichedmembranes and also provide strategies for the design of specific inhibitors that could potentially target plasmodial PI4KIII beta to combat malaria.