Mehta Sunali, Algie Michael, Al-Jabry Tariq, McKinney Cushla, Kannan Srinivasaraghavan, Verma Chandra S, Ma Weini, Zhang Jessie, Bartolec Tara K, Masamsetti V Pragathi, Parker Kim, Henderson Luke, Gould Maree L, Bhatia Puja, Harfoot Rhodri, Chircop Megan, Kleffmann Torsten, Cohen Scott B, Woolley Adele G, Cesare Anthony J, Braithwaite Antony
Department of Pathology, University of Otago, 9016 Dunedin, New Zealand.
Maurice Wilkins Centre for Biodiscovery, University of Otago, 9016 Dunedin, New Zealand.
Cancers (Basel). 2020 Sep 1;12(9):2473. doi: 10.3390/cancers12092473.
High levels of the cold shock protein Y-box-binding protein-1, YB-1, are tightly correlated with increased cell proliferation and progression. However, the precise mechanism by which YB-1 regulates proliferation is unknown. Here, we found that YB-1 depletion in several cancer cell lines and in immortalized fibroblasts resulted in cytokinesis failure and consequent multinucleation. Rescue experiments indicated that YB-1 was required for completion of cytokinesis. Using confocal imaging we found that YB-1 was essential for orchestrating the spatio-temporal distribution of the microtubules, β-actin and the chromosome passenger complex (CPC) to define the cleavage plane. We show that phosphorylation at six serine residues was essential for cytokinesis, of which novel sites were identified using mass spectrometry. Using atomistic modelling we show how phosphorylation at multiple sites alters YB-1 conformation, allowing it to interact with protein partners. Our results establish phosphorylated YB-1 as a critical regulator of cytokinesis, defining precisely how YB-1 regulates cell division.
高水平的冷休克蛋白Y盒结合蛋白1（YB-1）与细胞增殖增加和进展密切相关。然而，YB-1调节增殖的确切机制尚不清楚。在这里，我们发现，在几种癌细胞系和永生化成纤维细胞中YB-1缺失会导致胞质分裂失败并进而形成多核。拯救实验表明，胞质分裂的完成需要YB-1。使用共聚焦成像，我们发现YB-1对于协调微管、β-肌动蛋白和染色体乘客复合体（CPC）的时空分布以确定分裂平面至关重要。我们表明，六个丝氨酸残基的磷酸化对于胞质分裂至关重要，其中新的位点是通过质谱鉴定的。使用原子模型，我们展示了多个位点的磷酸化如何改变YB-1的构象，使其能够与蛋白质伴侣相互作用。我们的结果确立了磷酸化的YB-1作为胞质分裂的关键调节因子，精确地定义了YB-1如何调节细胞分裂。
