title: Distinct septin heteropolymers co-exist during multicellular development in the filamentous fungus Aspergillus nidulans.
abstract: Septins are important components of the cytoskeleton that are highly conserved in eukaryotes and play major roles in cytokinesis, patterning, and many developmental processes. Septins form heteropolymers which assemble into higher-order structures including rings, filaments, and gauzes. In contrast to actin filaments and microtubules, the molecular mechanism by which septins assemble is not well-understood. Here, we report that in the filamentous fungus Aspergillus nidulans, four core septins form heteropolymeric complexes. AspE, a fifth septin lacking in unicellular yeasts, interacts with only one of the core septins, and only during multicellular growth. AspE is required for proper localization of three of the core septins, and requires this same subset of core septins for its own unique cortical localization. The ΔaspE mutant lacks developmentally-specific septin higher-order structures and shows reduced spore production and slow growth with low temperatures and osmotic stress. Our results show that at least two distinct septin heteropolymer populations co-exist in A. nidulans, and that while AspE is not a subunit of either heteropolymer, it is required for assembly of septin higher-order structures found in multicellular development.
authors.affiliation: Department of Plant Biology, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Yainitza
authors.initials: Y
authors.lastname: Hernández-Rodríguez
authors.affiliation: Department of Plant Biology, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Masuo
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Darryl
authors.initials: D
authors.lastname: Johnson
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Ron
authors.initials: R
authors.lastname: Orlando
authors.affiliation: Department of Plant Biology, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Amy
authors.initials: A
authors.lastname: Smith
authors.affiliation: Department of Plant Biology, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Mara
authors.initials: M
authors.lastname: Couto-Rodriguez
authors.affiliation: Department of Plant Biology, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Michelle
authors.initials: M
authors.lastname: Momany
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009997:Osmotic Pressure / Q000502:physiology; D021381:Protein Transport; D058112:Septins / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D009097:Multienzyme Complexes; D058112:Septins