title: Microtubule-dependent membrane dynamics in Ustilago maydis: Trafficking and function of Rab5a-positive endosomes.
abstract: Long-distance trafficking of membranous structures along the cytoskeleton is crucial for secretion and endocytosis in eukaryotes. Molecular motors are transporting both secretory and endocytic vesicles along polarized microtubules. Here, we review the transport mechanism and biological function of a distinct subset of large vesicles marked by the G-protein Rab5a in the model microorganism Ustilago maydis. These Rab5a-positive endosomes shuttle bi-directionally along microtubules mediated by the Unc104/KIF1A-related motor Kin3 and dynein Dyn1/2. Rab5a-positive endosomes exhibit diverse functions during the life cycle of U. maydis. In haploid budding cells they are involved in cytokinesis and pheromone signaling. During filamentous growth endosomes are used for long-distance transport of mRNA, a prerequisite to maintain polarity most likely via local translation of specific proteins at both the apical and distal ends of filaments. Endosomal co-transport of mRNA constitutes a novel function of these membrane compartments supporting the view that endosomes function as multipurpose platforms.
authors.affiliation: Heinrich Heine University Düsseldorf; Center of Excellence on Plant Sciences (CEPLAS); Institute for Microbiology; Düsseldorf, Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Göhre
authors.forename: Evelyn
authors.initials: E
authors.lastname: Vollmeister
authors.forename: Michael
authors.initials: M
authors.lastname: Bölker
authors.forename: Michael
authors.initials: M
authors.lastname: Feldbrügge