Weiderhold Kimberly N, Fadri-Moskwik Maria, Pan Jing, Nishino Michiya, Chuang Carol, Deeraksa Arpaporn, Lin Sue-Hwa, Yu-Lee Li-Yuan
Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, Texas, United States of America.
Department of Medicine, Section of Allergy Immunology and Rheumatology, Baylor College of Medicine, Houston, Texas, United States of America.
PLoS One. 2016 Apr 13;11(4):e0153455. doi: 10.1371/journal.pone.0153455. eCollection 2016.
Nuclear distribution protein C (NudC) is a mitotic regulator that plays a role in cytokinesis. However, how NudC is regulated during cytokinesis remains unclear. Here, we show that NudC is phosphorylated by Aurora B, a kinase critical for cell abscission. NudC is co-localized with Aurora B at the midbody and co-immunoprecipitated with Aurora B in mitosis. Inhibition of Aurora B by ZM447439 reduced NudC phosphorylation, suggesting that NudC is an Aurora B substrate in vivo. We identified T40 on NudC as an Aurora B phosphorylation site. NudC depletion resulted in cytokinesis failure with a dramatic elongation of the intercellular bridge between daughter cells, sustained Aurora B activity at the midbody, and reduced cell abscission. These cytokinetic defects can be rescued by the ectopic expression of wild-type NudC. Reconstitution with T40A phospho-defective NudC was found to rescue the cytokinesis defect. In contrast, reconstitution with the T40D phospho-mimetic NudC was inefficient in supporting the completion of cytokinesis. These results suggest that that dynamic phosphorylation of NudC by Aurora B regulates cytokinesis.
核分布蛋白C（NudC）是一种有丝分裂调节因子，在胞质分裂中发挥作用。然而，NudC在胞质分裂过程中是如何被调控的仍不清楚。在这里，我们表明NudC被Aurora B磷酸化，Aurora B是一种对细胞脱离至关重要的激酶。NudC在中体与Aurora B共定位，并在有丝分裂中与Aurora B进行免疫共沉淀。ZM447439对Aurora B的抑制作用降低了NudC的磷酸化，表明NudC在体内是Aurora B的底物。我们确定NudC上的T40是Aurora B的磷酸化位点。NudC的缺失导致胞质分裂失败，子细胞之间的细胞间桥显著延长，中体处的Aurora B活性持续存在，细胞脱离减少。这些胞质分裂缺陷可以通过野生型NudC的异位表达来挽救。发现用T40A磷酸化缺陷型NudC进行重建可挽救胞质分裂缺陷。相反，用T40D磷酸化模拟型NudC进行重建在支持胞质分裂完成方面效率低下。这些结果表明，Aurora B对NudC的动态磷酸化调节胞质分裂。
