title: The lamin-A/C-LAP2α-BAF1 protein complex regulates mitotic spindle assembly and positioning.
abstract: Some nuclear proteins that are crucial in interphase relocate during the G2/M-phase transition in order to perform their mitotic functions. However, how they perform these functions and the underlying mechanisms remain largely unknown. Here, we report that a fraction of the nuclear periphery proteins lamin-A/C, LAP2α and BAF1 (also known as BANF1) relocate to the spindle and the cell cortex in mitosis. Knockdown of these proteins by using RNA interference (RNAi) induces short and fluffy spindle formation, and disconnection of the spindle from the cell cortex. Disrupting the microtubule assembly leads to accumulation of these proteins in the cell cortex, whereas depolymerizing the actin microfilaments results in the formation of short spindles. We further demonstrate that these proteins are part of a stable complex that links the mitotic spindle to the cell cortex and the spindle matrix by binding to spindle-associated dynein, the actin filaments in the cell cortex and the spindle matrix. Taken together, our findings unveil a unique mechanism where the nuclear periphery proteins lamin-A/C, LAP2α and BAF1 are assembled into a protein complex during mitosis in order to regulate assembly and positioning of the mitotic spindle.
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Qi
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Xu
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China.
authors.forename: He
authors.initials: H
authors.lastname: Ren
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China.
authors.forename: Si
authors.initials: S
authors.lastname: Li
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Lei
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China.
authors.forename: Qiaoyu
authors.initials: Q
authors.lastname: Lin
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China.
authors.forename: Lihao
authors.initials: L
authors.lastname: Wang
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Gu
authors.affiliation: Cancer Research Center, Peking University Hospital, Peking University, Beijing 100871, China.
authors.forename: Hongyin
authors.initials: H
authors.lastname: Zhang
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China jiangqing@pku.edu.cn zhangcm@pku.edu.cn.
authors.forename: Qing
authors.initials: Q
authors.lastname: Jiang
authors.affiliation: The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China jiangqing@pku.edu.cn zhangcm@pku.edu.cn.
authors.forename: Chuanmao
authors.initials: C
authors.lastname: Zhang
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D034904:Lamin Type A / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics*; D008870:Microtubules / Q000235:genetics; D008938:Mitosis / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics*; D034622:RNA Interference; D034741:RNA, Small Interfering; D008941:Spindle Apparatus / Q000235:genetics* / Q000378:metabolism
chemical_list: C501959:BANF1 protein, human; D004268:DNA-Binding Proteins; C494847:LMNA protein, human; D034904:Lamin Type A; D008565:Membrane Proteins; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; C093413:lamina-associated polypeptide 2
keywords: BAF1; Cell cycle; LAP2; Lamin-A/C; Spindle assembly; Spindle positioning