Subcellular location and activation of Tank Binding Kinase 1 (TBK1) govern precise progression through mitosis. Either loss of activated TBK1 or its sequestration from the centrosomes causes errors in mitosis and growth defects. Yet, what regulates its recruitment and activation on the centrosomes is unknown. We identified that NAK-associated protein 1 (NAP1) is essential for mitosis, binding to and activating TBK1, which both localize to centrosomes. Loss of NAP1 causes several mitotic and cytokinetic defects due to inactivation of TBK1. Our quantitative phosphoproteomics identified numerous TBK1 substrates that are not only confined to the centrosomes but are also associated with microtubules. Substrate motifs analysis indicates that TBK1 acts upstream of other essential cell cycle kinases like Aurora and PAK kinases. We also identified NAP1 as a TBK1 substrate phosphorylating NAP1 at S318 to promote its degradation by the ubiquitin proteasomal system. These data uncover an important distinct function for the NAP1–TBK1 complex during cell division.

中文翻译：

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NAK相关蛋白1/NAP1激活TBK1以确保准确的有丝分裂和胞质分裂


Tank 结合激酶 1 (TBK1) 的亚细胞定位和激活控制着有丝分裂的精确进展。活化的 TBK1 的丢失或其与中心体的隔离会导致有丝分裂错误和生长缺陷。然而，调节其在中心体上的招募和激活的因素尚不清楚。我们发现 NAK 相关蛋白 1 (NAP1) 对于有丝分裂至关重要，能够结合并激活 TBK1，而 TBK1 均定位于中心体。 NAP1 的缺失会因 TBK1 失活而导致多种有丝分裂和细胞因子缺陷。我们的定量磷酸蛋白质组学鉴定了许多 TBK1 底物，这些底物不仅限于中心体，而且还与微管相关。底物基序分析表明 TBK1 在其他重要细胞周期激酶（如 Aurora 和 PAK 激酶）的上游发挥作用。我们还鉴定出 NAP1 是 TBK1 底物，在 S318 处磷酸化 NAP1，以促进其被泛素蛋白酶体系统降解。这些数据揭示了 NAP1-TBK1 复合物在细胞分裂过程中的重要独特功能。