title: Lamin B receptor plays a role in stimulating nuclear envelope production and targeting membrane vesicles to chromatin during nuclear envelope assembly through direct interaction with importin beta.
abstract: Lamin B receptor (LBR), a chromatin and lamin binding protein in the inner nuclear membrane, has been proposed to play a vital role in nuclear envelope (NE) assembly. But the specific role for LBR in NE assembly remains unknown. In the present study, we show that overexpression of LBR causes membrane overproduction, inducing NE invagination and membrane stack formation, and that these processes require the transmembrane domain of LBR. Biochemical analysis shows that the N-terminal domain of LBR directly interacts with importin beta in a Ran sensitive and importin alpha independent manner. Using an in vitro NE assembly assay, we also demonstrate that blocking full length LBR binding sites on importin beta, by the addition of the LBR N-terminal domain inhibits the recruitment of LBR-containing vesicles to importin beta- or Ran-coated beads to form NE structure. Our results suggest that LBR is recruited to chromatin through direct interaction with importin beta to contribute to the fusion of membrane vesicles and formation of the NE.
authors.affiliation: The Key Laboratory of Cell Proliferation and Differentiation of Ministry of Education, The National Key Laboratory of Bio-membrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Shang
authors.initials: S
authors.lastname: Cai
authors.forename: Quanlong
authors.initials: Q
authors.lastname: Lv
authors.forename: Qing
authors.initials: Q
authors.lastname: Jiang
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhang
authors.lastname: Sodmergen
authors.forename: Zhonghe
authors.initials: Z
authors.lastname: Zhai
authors.forename: Chuanmao
authors.initials: C
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D021961:Cell Membrane Structures / Q000378:metabolism* / Q000648:ultrastructure; D002843:Chromatin / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D005456:Fluorescent Dyes; D017353:Gene Deletion; D005982:Glutathione Transferase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007211:Indoles; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009685:Nuclear Envelope / Q000378:metabolism* / Q000648:ultrastructure; D009865:Oocytes / Q000737:chemistry; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic; D014981:Xenopus; D028961:beta Karyopherins / Q000737:chemistry / Q000378:metabolism*; D000097682:Lamin B Receptor
chemical_list: D002843:Chromatin; D005456:Fluorescent Dyes; D005982:Glutathione Transferase; D049452:Green Fluorescent Proteins; D007211:Indoles; D018160:Receptors, Cytoplasmic and Nuclear; D028961:beta Karyopherins; D000097682:Lamin B Receptor; C007293:DAPI