title: Endosomal assembly and transport of heteromeric septin complexes promote septin cytoskeleton formation.
abstract: Septins are conserved cytoskeletal structures functioning in a variety of biological processes including cytokinesis and cell polarity. A wealth of information exists on the heterooligomeric architecture of septins and their subcellular localization at distinct sites. However, the precise mechanisms of their subcellular assembly and their intracellular transport are unknown. Here, we demonstrate that endosomal transport of septins along microtubules is crucial for formation of higher-order structures in the fungus Ustilago maydis Importantly, endosomal septin transport is dependent on each individual septin providing strong evidence that septin heteromeric complexes are assembled on endosomes. Furthermore, endosomal trafficking of all four septin mRNAs is required for endosomal localization of their translation products. Based on these results, we propose that local translation promotes the assembly of newly synthesized septins in heteromeric structures on the surface of endosomes. This is important for the long-distance transport of septins and the efficient formation of the septin cytoskeleton.
authors.affiliation: Department of Biology, Institute for Microbiology, Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, 40204 Düsseldorf, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Zander
authors.affiliation: Department of Biology, Institute for Microbiology, Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, 40204 Düsseldorf, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Baumann
authors.affiliation: Department of Biology, Center for Advanced Imaging (CAi), Heinrich Heine University Düsseldorf, 40204 Düsseldorf, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Weidtkamp-Peters
authors.affiliation: Department of Biology, Institute for Microbiology, Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, 40204 Düsseldorf, Germany feldbrue@hhu.de.
authors.forename: Michael
authors.identifier: 0000-0003-0046-983X
authors.initials: M
authors.lastname: Feldbrügge
mesh_terms: D003599:Cytoskeleton / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D008954:Models, Biological; D011485:Protein Binding; D055503:Protein Multimerization; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D058112:Septins / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism; D014588:Ustilago / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D012333:RNA, Messenger; D058112:Septins
keywords: Early endosomes; RNA recognition motif; Septin; mRNA transport