Structure of the human FERRY Rab5 effector complex

Long-range mRNA transport is crucial for the spatio-temporal regulation of gene expression, and its malfunction leads to neurological disorders. The pentameric FERRY Rab5 effector complex is the molecular link between mRNA and early endosomes in mRNA intracellular distribution. Here, we determine the cryo-EM structure of the human FERRY complex, composed of Fy-1 to Fy-5. The structure reveals a clamp-like architecture, where two arm-like appendages of Fy-2 and a Fy-5 dimer, protrude from the central Fy-4 dimer. The coiled-coil domains of Fy-2 are flexible and project into opposite directions from the core. While the Fy-2 C-terminal coiled-coil acts as binding region for Fy-1/3 and Rab5, both coiled-coils and Fy-5 concur to bind mRNA. Mutations causing truncations of Fy-2 in patients with neurological disorders impair Rab5 binding or FERRY complex assembly. Thus, Fy-2 serves as a binding hub connecting all five complex subunits and mediating the binding to mRNA and early endosomes via Rab5. The FERRY structure provides novel mechanistic insights into long-distance mRNA transport.