title: Actin-Interacting Protein 1 Contributes to Intranuclear Rod Assembly in Dictyostelium discoideum.
abstract: Intranuclear rods are aggregates consisting of actin and cofilin that are formed in the nucleus in consequence of chemical or mechanical stress conditions. The formation of rods is implicated in a variety of pathological conditions, such as certain myopathies and some neurological disorders. It is still not well understood what exactly triggers the formation of intranuclear rods, whether other proteins are involved, and what the underlying mechanisms of rod assembly or disassembly are. In this study, Dictyostelium discoideum was used to examine appearance, stages of assembly, composition, stability, and dismantling of rods. Our data show that intranuclear rods, in addition to actin and cofilin, are composed of a distinct set of other proteins comprising actin-interacting protein 1 (Aip1), coronin (CorA), filactin (Fia), and the 34 kDa actin-bundling protein B (AbpB). A finely tuned spatio-temporal pattern of protein recruitment was found during formation of rods. Aip1 is important for the final state of rod compaction indicating that Aip1 plays a major role in shaping the intranuclear rods. In the absence of both Aip1 and CorA, rods are not formed in the nucleus, suggesting that a sufficient supply of monomeric actin is a prerequisite for rod formation.
authors.affiliation: Department of Cell Biology (Anatomy III), Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany.
authors.forename: Hellen C
authors.initials: HC
authors.lastname: Ishikawa-Ankerhold
authors.affiliation: Department of Cell Biology (Anatomy III), Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany.
authors.forename: Wioleta
authors.initials: W
authors.lastname: Daszkiewicz
authors.affiliation: Department of Cell Biology (Anatomy III), Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schleicher
authors.affiliation: Department of Cell Biology (Anatomy III), Biomedical Center, LMU Munich, 82152 Planegg-Martinsried, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Müller-Taubenberger
mesh_terms: D000199:Actins / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D004023:Dictyostelium / Q000166:cytology / Q000378:metabolism*; D036681:Fluorescence Recovery After Photobleaching; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism*; D058105:Polymerization; D015800:Protozoan Proteins / Q000378:metabolism*; D013997:Time Factors
chemical_list: D000199:Actins; D008840:Microfilament Proteins; D015800:Protozoan Proteins; C115237:actin interacting protein 1; D049452:Green Fluorescent Proteins