Endosome-coupled mRNA transport

Active transport and local translation of mRNAs ensure the appropriate spatial organization of proteins within cells. Recent work has shown that this process is intricately connected to membrane trafficking. We study the model organism Ustilago maydis. In highly polarized cells of this fungus microtubule-dependent co-transport of mRNAs and endosomes is essential for efficient polar growth. We discuss a novel concept of endosome-coupled translation that loads shuttling endosomes with septin cargo, a process important for correct septin filamentation. Key players are RNA-binding proteins containing RNA recognition motifs for mRNA binding as well as Mademoiselle domains for protein/protein interaction. Here, new insights on protein RNA as well as protein-protein interactions will be presented. Interestingly, evidence is accumulating that RNA and membrane trafficking are also tightly interwoven in higher eukaryotes suggesting that this phenomenon is a common theme and not an exception restricted to fungi.