Fujita Ikumi, Yamashita Akira, Yamamoto Masayuki
Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Laboratory for Cell Asymmetry, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Laboratory of Cell Responses, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
J Cell Sci. 2015 Apr 15;128(8):1555-67. doi: 10.1242/jcs.163840. Epub 2015 Mar 3.
Chromosome movement during meiosis is crucial for homologous pairing and meiotic recombination. During meiotic prophase in fission yeast, rapid nuclear migration is dependent on cytoplasmic dynein, which is anchored to the cell cortex and pulls microtubules, thereby driving nuclear migration. However, the precise mechanisms underlying dynein localization and activation remain unclear. Here, we identified three subunits of dynactin in fission yeast: Arp1, Mug5 and Jnm1 (also known as Mug1). These subunits transiently colocalized with dynein foci at the cell cortex and were essential for the cortical anchoring of dynein. Cortical factor Num1 (also known as Mcp5), which was also required for dynein anchoring, bound to dynein independently of dynactin. Whereas Num1 suppressed the sliding of dynein foci along the cortex, Arp1, Mug5 and Jnm1 were involved in the regulation of shrinkage and bundling of microtubules. From these data, we propose that dynein anchoring is established by cooperation of transient assembly of dynactin and function of Num1 at the cell cortex.
减数分裂过程中的染色体运动对于同源配对和减数分裂重组至关重要。在裂殖酵母的减数分裂前期，快速的核迁移依赖于细胞质动力蛋白，该蛋白锚定在细胞皮层并拉动微管，从而驱动核迁移。然而，动力蛋白定位和激活的精确机制仍不清楚。在这里，我们鉴定了裂殖酵母中动力蛋白激活蛋白的三个亚基：Arp1、Mug5和Jnm1（也称为Mug1）。这些亚基在细胞皮层与动力蛋白焦点短暂共定位，并且对于动力蛋白在皮层的锚定至关重要。皮层因子Num1（也称为Mcp5），动力蛋白锚定也需要它，它独立于动力蛋白激活蛋白与动力蛋白结合。虽然Num1抑制动力蛋白焦点沿皮层的滑动，但Arp1、Mug5和Jnm1参与微管收缩和成束的调节。根据这些数据，我们提出动力蛋白的锚定是通过动力蛋白激活蛋白的瞬时组装与Num1在细胞皮层的功能协同作用而建立的。
