Bicaudal D2, dynein, and kinesin-1 associate with nuclear pore complexes and regulate centrosome and nuclear positioning during mitotic entry.
Bicaudal D2, dynein, and kinesin-1 associate with nuclear pore complexes and regulate centrosome and nuclear positioning during mitotic entry.
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DOI：
10.1371/journal.pbio.1000350
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发表时间：
2010-04-06
期刊：
影响因子：
9.8
通讯作者：
Akhmanova A
中科院分区：
文献类型：
--
作者：
Splinter D;Tanenbaum ME;Lindqvist A;Jaarsma D;Flotho A;Yu KL;Grigoriev I;Engelsma D;Haasdijk ED;Keijzer N;Demmers J;Fornerod M;Melchior F;Hoogenraad CC;Medema RH;Akhmanova A
哺乳动物Bicaudal D2是在有丝分裂开始之前在核定位期间细胞质马达蛋白和核之间缺失的分子连接。BICD 2是果蝇Bicaudal D的两种哺乳动物同源物之一，Dicaudal D是微管马达及其货物之间的进化上保守的衔接子，先前显示将囊泡和mRNP复合物连接到动力蛋白马达。在这里，我们确定了一个G2特异性的作用BICD 2在分裂细胞的核和中心体的相对定位。通过结合质谱，生物化学和细胞生物学方法，我们表明，核孔复合物（NPC）组件RanBP 2直接结合BICD 2，并招募它的NPC特异性在细胞周期的G2期。BICD 2，反过来，招募动力蛋白-动力蛋白到NPC，因此需要在有丝分裂进入之前保持中心体紧密地束缚在细胞核上。当RNA干扰介导的耗竭或抗体显微注射抑制动力蛋白功能时，中心体和细胞核在G2晚期被主动推开，我们表明这是由于驱动蛋白-1的作用。令人惊讶的是，BICD 2的耗竭抑制细胞核和细胞质NPC的动力蛋白和驱动蛋白-1依赖性运动，表明BICD 2不仅是核孔处动力蛋白功能所需的，而且也是驱动蛋白-1的拮抗活性所需的。我们的研究表明，细胞核是动力蛋白和驱动蛋白-1马达的相反活动，BICD 2有助于细胞核和中心体定位之前，有丝分裂进入通过调节动力蛋白和驱动蛋白-1。基于微管的双向运输负责定位各种各样的细胞器，但基于微管的马达向其货物的募集及其激活的分子机制仍然知之甚少。特别是，在细胞分裂开始之前，参与核和中心体定位的重要过程的分子球员是未知的。在这项研究中，我们专注于果蝇Bicaudal D，微管负端定向动力蛋白-动力蛋白马达复合物的适配器的哺乳动物同源物之一的功能。以前，果蝇Bicaudal D和它的哺乳动物同源物被证明作为动力蛋白马达和mRNP复合物或分泌囊泡之间的接头。在这里，我们确定了哺乳动物Bicaudal D2（BICD 2）的新货物-细胞核。我们表明，BICD 2特异性结合细胞分裂周期的G2期细胞的核孔复合物。我们还表明，这种相互作用所需的G2特异性的招聘的动力蛋白的核膜，从而正确定位的细胞核相对于有丝分裂开始前的中心体。此外，我们的研究结果表明，马达蛋白驱动蛋白-1反对动力蛋白的活动在这一过程中，并需要BICD 2的活动。因此，我们的研究揭示了BICD 2作为关键的分子适配器，允许分子马达在细胞分裂前调节核和中心体定位。
Mammalian Bicaudal D2 is the missing molecular link between cytoplasmic motor proteins and the nucleus during nuclear positioning prior to the onset of mitosis. BICD2 is one of the two mammalian homologues of the Drosophila Bicaudal D, an evolutionarily conserved adaptor between microtubule motors and their cargo that was previously shown to link vesicles and mRNP complexes to the dynein motor. Here, we identified a G2-specific role for BICD2 in the relative positioning of the nucleus and centrosomes in dividing cells. By combining mass spectrometry, biochemical and cell biological approaches, we show that the nuclear pore complex (NPC) component RanBP2 directly binds to BICD2 and recruits it to NPCs specifically in G2 phase of the cell cycle. BICD2, in turn, recruits dynein-dynactin to NPCs and as such is needed to keep centrosomes closely tethered to the nucleus prior to mitotic entry. When dynein function is suppressed by RNA interference-mediated depletion or antibody microinjection, centrosomes and nuclei are actively pushed apart in late G2 and we show that this is due to the action of kinesin-1. Surprisingly, depletion of BICD2 inhibits both dynein and kinesin-1-dependent movements of the nucleus and cytoplasmic NPCs, demonstrating that BICD2 is needed not only for the dynein function at the nuclear pores but also for the antagonistic activity of kinesin-1. Our study demonstrates that the nucleus is subject to opposing activities of dynein and kinesin-1 motors and that BICD2 contributes to nuclear and centrosomal positioning prior to mitotic entry through regulation of both dynein and kinesin-1. Bidirectional microtubule-based transport is responsible for the positioning of a large variety of cellular organelles, but the molecular mechanisms underlying the recruitment of microtubule-based motors to their cargoes and their activation remain poorly understood. In particular, the molecular players involved in the important processes of nuclear and centrosomal positioning prior to the onset of cell division are not known. In this study we focus on the function of one of the mammalian homologues of Drosophila Bicaudal D, an adaptor for the microtubule minus-end-directed dynein-dynactin motor complex. Previously, Drosophila Bicaudal D and its mammalian homologues were shown to act as linkers between the dynein motor and mRNP complexes or secretory vesicles. Here, we identify a new cargo for mammalian Bicaudal D2 (BICD2)–the nucleus. We show that BICD2 specifically binds to nuclear pore complexes in cells in G2 phase of the cell division cycle. We also show that this interaction is required for G2-specific recruitment of dynein to the nuclear envelope and thus for proper positioning of the nucleus relative to centrosomes prior to the onset of mitosis. Further, our findings demonstrate that the motor protein kinesin-1 opposes dynein's activity during this process and requires BICD2 for its activity. Our study therefore reveals BICD2 as the critical molecular adaptor that allows molecular motors to regulate nuclear and centrosomal positioning before cell division.
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LIS1和NDEL1会影响神经干细胞中核膜分解的时机。
影响因子：
7.8
作者：
Hebbar, Sachin;Mesngon, Mariano T.;Guillotte, Aimee M.;Desai, Bhavim;Ayala, Ramses;Smith, Deanna S.
通讯作者：
Smith, Deanna S.
DOI：
10.1073/pnas.1332608100
发表时间：
2003-06-24
影响因子：
11.1
作者：
de Boer, E;Rodriguez, P;Strouboulis, J
通讯作者：
Strouboulis, J
影响因子：
11.8
作者：
Grigoriev, Ilya;Splinter, Daniel;Akhmanova, Anna
通讯作者：
Akhmanova, Anna
影响因子：
4
作者：
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通讯作者：
Goldman, RD
影响因子：
4.8
作者：
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通讯作者：
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