GTP is an essential source of energy that supports a large array of cellular mechanochemical structures ranging from protein synthesis machinery to cytoskeletal apparatus for maintaining the cell cycle. However, GTP regulation during the cell cycle has been difficult to investigate because of heterogenous levels of GTP in asynchronous cell cycles and genetic redundancy of the GTP-generating enzymes. Here, in the unicellular red algae Cyanidioschyzon merolae, we demonstrated that the ATP-GTP-converting enzyme DYNAMO2 is an essential regulator of global GTP levels during the cell cycle. The cell cycle of C. merolae can be highly synchronized by light/dark stimulations to examine GTP levels at desired time points. Importantly, the genome of C. merolae encodes only two isoforms of the ATP-GTP-converting enzyme, namely DYNAMO1 and DYNAMO2. DYNAMO1 regulates organelle divisions, whereas DYNAMO2 is entirely localized in the cytoplasm. DYNAMO2 protein levels increase during the S-M phases, and changes in GTP levels are correlated with these DYNAMO2 protein levels. These results indicate that DYNAMO2 is a potential regulator of global GTP levels during the cell cycle.

中文翻译：

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核苷二磷酸激酶蛋白DYNAMO2的动力学与Cyanidioschyzon merolae细胞周期中全球GTP水平的变化相关。

GTP是一种重要的能量来源，可支持从蛋白质合成机器到维持细胞周期的细胞骨架设备等各种细胞机械化学结构。但是，由于异步细胞周期中GTP的异质水平和GTP产生酶的遗传冗余，因此很难研究细胞周期中的GTP调控。在这里，在单细胞红藻Cyanidioschyzon merolae中，我们证明了ATP-GTP转换酶DYNAMO2是细胞周期中全球GTP水平的重要调节剂。可以通过光/暗刺激高度刺激梅花弯曲杆菌的细胞周期，以检查所需时间点的GTP水平。重要的是，弯曲杆菌的基因组仅编码ATP-GTP转换酶的两种同工型，即DYNAMO1和DYNAMO2。DYNAMO1调节细胞器的分裂，而DYNAMO2则完全位于细胞质中。DYNAMO2蛋白水平在SM期增加，而GTP水平的变化与这些DYNAMO2蛋白水平相关。这些结果表明，DYNAMO2是细胞周期中全球GTP水平的潜在调节剂。