CNRS UMR 6290, IGDR, Rennes, CS34317, 35043 Rennes, France.
J Cell Sci. 2012 Jun 15;125(Pt 12):2844-52. doi: 10.1242/jcs.058081. Epub 2012 Mar 27.
MNK1 is a serine/threonine kinase identified as a target for MAP kinase pathways. Using chemical drug, kinase-dead expression or knockdown by RNA interference, we show that inhibition of MNK1 induces the formation of multinucleated cells, which can be rescued by expressing a form of MNK1 that is resistant to RNA interference. We found that the active human form of MNK1 localises to centrosomes, spindle microtubules and the midbody. Time-lapse recording of MNK1-depleted cells displays cytokinesis defects, as daughter cells fuse back together. When MNK1 activity was inhibited, no microtubule defect at the midbody was detected, however, anchorage of the membrane vesicle at the midbody was impaired as lumenal GFP-positive vesicles did not accumulate at the midbody. At the molecular level, we found that centriolin localisation was impaired at the midbody in MNK1-depleted cells. As a consequence, endobrevin - a v-SNARE protein implicated in the abscission step - was not properly localised to the midbody. Altogether, our data show that MNK1 activity is required for abscission.
MNK1 是一种丝氨酸/苏氨酸激酶，被确定为 MAP 激酶途径的靶标。通过化学药物、激酶失活表达或 RNA 干扰敲低，我们表明抑制 MNK1 诱导多核细胞的形成，而表达对 RNA 干扰有抗性的 MNK1 形式可以挽救这种现象。我们发现，活性人源 MNK1 定位于中心体、纺锤体微管和中体。对 MNK1 耗尽细胞进行延时拍摄显示胞质分裂缺陷，因为子细胞重新融合在一起。当 MNK1 活性被抑制时，在中体处没有检测到微管缺陷，然而，膜囊泡在中体处的锚定受到损害，因为腔 GFP 阳性囊泡没有在中体处积累。在分子水平上，我们发现 MNK1 耗尽细胞的中体处的中心体蛋白定位受损。结果，内布雷文 - 一种参与分离步骤的 v-SNARE 蛋白 - 不能正确定位于中体。总之，我们的数据表明 MNK1 活性对于分离是必需的。
