Direct binding of lg12 to LGN during mitosis and its requirement for normal cell division
Direct binding of lg12 to LGN during mitosis and its requirement for normal cell division
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DOI：
10.1074/jbc.c400440200
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发表时间：
2005-02-25
影响因子：
4.8
通讯作者：
Takai, Y
中科院分区：
文献类型：
--
作者：
Yasumi, M;Sakisaka, T;Takai, Y
果蝇肿瘤抑制蛋白致死（2）巨型幼虫（1（2）gl）通过与aPKC-Par-6复合物相互作用参与发育期间的不对称细胞分裂和上皮细胞极性。我们在这里发现，Lgl 2，一种1（2）gl的哺乳动物同源物，直接结合到LGN，一种在HEK 293细胞中可被切割的伴侣的哺乳动物同源物。Lgl2的C-末端尾以约56nm的Kd值与LGN结合。内源性Lgl2与aPKC、Par-6和LGN形成复合物。这种复合物的形成增强了中期的同步化细胞的处理与胸苷和nocodazole。在中期细胞的细胞周围，复合物的免疫荧光染色最强。Lgl2的C-末端尾的过表达诱导核有丝分裂器蛋白NuMA的错误定位和有丝分裂期间有丝分裂纺锤体的解体，最终导致多个微核的形成。内源性Lgl（Lgl 1和Lgl 2）的敲低也诱导有丝分裂纺锤体的解体，从而导致多个微核的形成。Lg12和LGN之间的结合通过调节LGN-NuMA复合物的形成在有丝分裂纺锤体组织中发挥作用。这些结果表明，Lg12形成Lgl2（.）Par-6（.）aPKC（.）LGN复合物，其响应有丝分裂信号以建立正常的细胞分裂。
The Drosophila tumor suppressor protein lethal (2) giant larvae (1(2)gl) is involved in asymmetric cell division during development and epithelial cell polarity through interaction with the aPKC-Par-6 complex. We showed here that Lgl2, a mammalian homolog of 1(2)gl, directly bound to LGN, a mammalian homolog of Partner of inscuteable in HEK293 cells. The C-terminal tail of Lgl2 bound to LGN with a K-d value of about 56 nm. Endogenous Lgl2 formed a complex with aPKC, Par-6, and LGN. This complex formation was enhanced in metaphase of the synchronized cells by treatment with thymidine and nocodazole. Immunofluoreseence staining of the complex was the strongest at the cell periphery of the metaphase cells. Overexpression of the C-terminal tail of Lgl2 induced mis-localization of the nuclear mitotic apparatus protein NuMA and disorganization of the mitotic spindle during mitosis, eventually causing formation of multiple micronuclei. Knockdown of endogenous Lgl (Lgl1 and Lgl2) also induced disorganization of the mitotic spindle, thereby causing formation of multiple micronuclei. The binding between Lg12 and LGN played a role in the mitotic spindle organization through regulating formation of the LGN-NuMA complex. These results indicate that Lg12 forms a Lgl2(.)Par-6(.)aPKC(.)LGN complex, which responds to mitotic signaling to establish normal cell division.