Temporal Control of Nuclear Envelope Assembly by Phosphorylation of Lamin B Receptor

• Main Authors: Tseng, Li-Chuan, 曾莉琄
• Other Authors: Chen, Rey-Huei
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/85531560651961654127

博士 === 國防醫學院 === 生命科學研究所 === 100 === In metazoans, the nuclear envelope (NE) breaks down during mitosis and reassembles at the end of mitosis. The reassembly of NE happens precisely after proper segregation of sister chromatids to avoid genomic instability. The mechanism of the temporal control for the NE reassembly is unknown. Herein, I found that the temporal control of NE reassembly is determined by the counter balance between the phosphorylation by Cdk1 and dephosphorylation by PP1/2A in vivo. The inner nuclear membrane protein lamin B receptor (LBR) is phosphorylated by Cdk1 at serine 71 and serine 86, which prevents the premature attachment of mitotic ER in early anaphase. The globular I domain of LBR is an important region for the chromatin binding that is inhibited by the globular II domain of LBR upon phosphorylation by Cdk1. In addition, I found that the binding ability of LBR also affects the dissociation of NE during nuclear envelope breakdown. The activation of Aurora B and the attenuated chromosome-binding ability of LBR contribute to the NEBD in early mitosis.