Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK.
University College London Cancer Institute, London, UK.
Nat Struct Mol Biol. 2018 Dec;25(12):1093-1102. doi: 10.1038/s41594-018-0152-3. Epub 2018 Nov 19.
The cell division cycle consists of a series of temporally ordered events. Cell cycle kinases and phosphatases provide key regulatory input, but how the correct substrate phosphorylation and dephosphorylation timing is achieved is incompletely understood. Here we identify a PxL substrate recognition motif that instructs dephosphorylation by the budding yeast Cdc14 phosphatase during mitotic exit. The PxL motif was prevalent in Cdc14-binding peptides enriched in a phage display screen of native disordered protein regions. PxL motif removal from the Cdc14 substrate Cbk1 delays its dephosphorylation, whereas addition of the motif advances dephosphorylation of otherwise late Cdc14 substrates. Crystal structures of Cdc14 bound to three PxL motif substrate peptides provide a molecular explanation for PxL motif recognition on the phosphatase surface. Our results illustrate the sophistication of phosphatase-substrate interactions and identify them as an important determinant of ordered cell cycle progression.
细胞分裂周期由一系列时间顺序排列的事件组成。细胞周期激酶和磷酸酶提供了关键的调节输入，但正确的底物磷酸化和去磷酸化时间是如何实现的还不完全清楚。在这里，我们确定了一个 PxL 底物识别基序，该基序指导芽殖酵母 Cdc14 磷酸酶在有丝分裂退出时进行去磷酸化。该 PxL 基序在噬菌体展示筛选天然无规蛋白区域的 Cdc14 结合肽中很常见。从 Cdc14 底物 Cbk1 中去除 PxL 基序会延迟其去磷酸化，而添加该基序则会加速 otherwise late Cdc14 底物的去磷酸化。Cdc14 结合三个 PxL 基序底物肽的晶体结构为磷酸酶表面上 PxL 基序识别提供了分子解释。我们的结果说明了磷酸酶-底物相互作用的复杂性，并将其确定为有序细胞周期进程的重要决定因素。
