title: Temporal control of nuclear envelope assembly by phosphorylation of lamin B receptor.
abstract: The nuclear envelope of metazoans disassembles during mitosis and reforms in late anaphase after sister chromatids have well separated. The coordination of these mitotic events is important for genome stability, yet the temporal control of nuclear envelope reassembly is unknown. Although the steps of nuclear formation have been extensively studied in vitro using the reconstitution system from egg extracts, the temporal control can only be studied in vivo. Here, we use time-lapse microscopy to investigate this process in living HeLa cells. We demonstrate that Cdk1 activity prevents premature nuclear envelope assembly and that phosphorylation of the inner nuclear membrane protein lamin B receptor (LBR) by Cdk1 contributes to the temporal control. We further identify a region in the nucleoplasmic domain of LBR that inhibits premature chromatin binding of the protein. We propose that this inhibitory effect is partly mediated by Cdk1 phosphorylation. Furthermore, we show that the reduced chromatin-binding ability of LBR together with Aurora B activity contributes to nuclear envelope breakdown. Our studies reveal for the first time a mechanism that controls the timing of nuclear envelope reassembly through modification of an integral nuclear membrane protein.
authors.affiliation: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan.
authors.forename: Li-Chuan
authors.initials: LC
authors.lastname: Tseng
authors.forename: Rey-Huei
authors.initials: RH
authors.lastname: Chen
mesh_terms: D019943:Amino Acid Substitution; D000705:Anaphase; D064107:Aurora Kinase B; D064127:Aurora Kinases; D001665:Binding Sites; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D008938:Mitosis; D016297:Mutagenesis, Site-Directed; D009685:Nuclear Envelope / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D054645:Protein Phosphatase 1 / Q000378:metabolism; D054648:Protein Phosphatase 2 / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011687:Purines / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D000077546:Roscovitine; D059010:Single-Cell Analysis; D059008:Time-Lapse Imaging; D000097682:Lamin B Receptor
chemical_list: D064107:Aurora Kinase B; D064127:Aurora Kinases; D016203:CDC2 Protein Kinase; D002843:Chromatin; D049452:Green Fluorescent Proteins; D054645:Protein Phosphatase 1; D054648:Protein Phosphatase 2; D017346:Protein Serine-Threonine Kinases; D011687:Purines; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D000077546:Roscovitine; D000097682:Lamin B Receptor; C576921:AURKB protein, human