Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
Open Biol. 2020 Oct;10(10):200189. doi: 10.1098/rsob.200189. Epub 2020 Oct 14.
Polo-like kinases (Plks) are evolutionarily conserved serine/threonine protein kinases playing crucial roles during multiple stages of mitosis and cytokinesis in yeast and animals. Plks are characterized by a unique Polo-box domain, which plays regulatory roles in controlling Plk activation, interacting with substrates and targeting Plk to specific subcellular locations. Plk activity and protein abundance are subject to temporal and spatial control through transcription, phosphorylation and proteolysis. In the early branching protists, Plk orthologues are present in some taxa, such as kinetoplastids and , but are lost in apicomplexans, such as . Works from characterizing a Plk orthologue in , a kinetoplastid protozoan, discover its essential roles in regulating the inheritance of flagellum-associated cytoskeleton and the initiation of cytokinesis, but not any stage of mitosis. These studies reveal evolutionarily conserved and species-specific features in the control of Plk activation, substrate recognition and protein abundance, and suggest the divergence of Plk function and regulation for specialized needs in this flagellated unicellular eukaryote.
丝氨酸/苏氨酸蛋白激酶 Polo 样激酶（Plk）在酵母和动物的有丝分裂和胞质分裂的多个阶段中发挥着至关重要的作用，它们在进化上是保守的。Plk 的特征是具有独特的 Polo 框结构域，该结构域在控制 Plk 激活、与底物相互作用以及将 Plk 靶向特定亚细胞位置方面发挥着调节作用。Plk 的活性和蛋白丰度通过转录、磷酸化和蛋白水解作用受到时空控制。在早期分支的原生生物中，一些分类群中存在 Plk 同源物，例如动基体生物和 ，但在顶复门生物中丢失了，例如 。对动基体原生动物 中的 Plk 同源物进行特征描述的研究发现，它在调节与鞭毛相关的细胞骨架的遗传和胞质分裂的起始中发挥着重要作用，但在有丝分裂的任何阶段都不起作用。这些研究揭示了 Plk 激活、底物识别和蛋白丰度的控制在进化上是保守的和具有物种特异性的，并表明 Plk 的功能和调节发生了分化，以满足这种有鞭毛的单细胞真核生物的特殊需求。
