title: Lamin A reassembly at the end of mitosis is regulated by its SUMO-interacting motif.
abstract: Modification of proteins with small ubiquitin-related modifier (SUMO; SUMOylation) is involved in the regulation of various biological processes. Recent studies have demonstrated that noncovalent associations between SUMOylated proteins and co-operative proteins containing SUMO-interacting motifs (SIMs) are important for the spatiotemporal organization of many protein complexes. In this study, we demonstrate that interactions between lamin A, a major component of the nuclear lamina, and SUMO isoforms are dependent on one of the four SIMs (SIM3) resided in lamin A polypeptide in vitro. Live cell imaging and immunofluorescence staining showed that SIM3 is required for accumulation of lamin A on the chromosomes during telophase, and subsequent evaluation of a panel of deletion mutants determined that a 156-amino acid region spanning the carboxyl-terminal Ig-fold domain of lamin A is sufficient for this accumulation. Notably, mutation of SIM3 abrogated the dephosphorylation of mitosis-specific phosphorylation at Ser-22 of lamin A, which normally occurs during telophase, and the subsequent nuclear lamina reorganization. Furthermore, expression of a conjugation-defective SUMO2 mutant, which was previously shown to inhibit endogenous SUMOylation in a dominant-negative manner, also impaired the accumulation of wild type lamin A on telophase chromosomes. These findings suggest that interactions between SIM3 of lamin A and a putative SUMO2-modified protein plays an important role in the reorganization of the nuclear lamina at the end of mitosis.
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Takanobu
authors.initials: T
authors.lastname: Moriuchi
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kuroda
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Fumiya
authors.initials: F
authors.lastname: Kusumoto
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Osumi
authors.affiliation: Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678-1297, Japan. Electronic address: fhirose@sci.u-hyogo.ac.jp.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Hirose
mesh_terms: D002877:Chromosomes, Human / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D034904:Lamin Type A / Q000737:chemistry / Q000378:metabolism*; D008938:Mitosis; D034881:Nuclear Lamina / Q000378:metabolism; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D021381:Protein Transport; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism; D058207:Sumoylation
chemical_list: D034904:Lamin Type A; C117909:SUMO2 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins
keywords: Lamin A; Mitosis; SUMO-interacting motif; The nuclear reassembly