LAUSR

Early endosomes bind certain mRNAs and are thought to facilitate translation thereon, but the mechanism underlying this function is not known. This study identifies a novel Rab 5 effector complex, the five-subunit endosomal Rab5 and the RNA/ribosome ntermediary (FERRY), which localizes to endosomes in neurons. By combining biochemical- and fluorescence-based assays, the authors find that FERRY binds specific mRNA transcripts, mostly those encoding mitochondrial proteins, and is found in proximity to mitochondria. This study proposes that early endosomes function both as platforms for particular mRNA translation and vehicles for mRNA delivery to mitochondria. Considering that mutations in FERRY subunits are associated with neurological disorders, these findings shed new light on the importance of endosomal-mitochondrial cross-talk in neurons and likely other cell types.