Polo Kinase and Cytokinesis Initiation in Mammalian Cells: Harnessing the Awesome Power of Chemical Genetics

Centralspindlin assembly and 2 phosphorylations on MgcRacGAP by Polo-like kinase 1 initiate Ect2 binding in early cytokinesis

“…[24][25][26] Plk1 co-localizes with centralspindlin to the microtubule midzone in anaphase, 27 but the function of this pool is concealed from genetic techniques by essential Plk1 functions in early mitosis. 28 Chemical inactivation of Plk1 activity at anaphase onset has demonstrated that Plk1 is required for cytokinesis and Ect2 localization. [29][30][31][32] Plk1 first phosphorylates PRC1 at the spindle midzone, inducing its recruitment to the central spindle complex.…”

Plk1 Self-Organization and Priming Phosphorylation of HsCYK-4 at the Spindle Midzone Regulate the Onset of Division in Human Cells

“…In contrast to Cdk1, other mitotic kinases, including Polo-like kinase 1 (Plk1) and Aurora B, regulate cytokinesis positively [1]–[3],[20]–[22]. Because chronic Plk1 inactivation results in profound mitotic defects that trigger the spindle checkpoint and cause a terminal cell-cycle arrest in prometaphase, Plk1's role during the initiation of cytokinesis was not discovered until the recent advent of fast-acting chemical inhibitors [23]–[27].…”

“…Exposure of Plk1 as cells to one such analog, 3-MB-PP1, abrogates all known mitotic and cytokinetic functions of the kinase, albeit on a 100-fold shorter time scale than gene deletion or RNAi. Importantly, 3-MB-PP1 is inert when applied to cells expressing wild-type Plk1, validating this compound as an allele-specific inhibitor in vivo [22]. In this Research Article, we leverage this system to modulate not only the timing of kinase signaling but also its geometry.…”

High Mitotic Activity of Polo-like Kinase 1 Is Required for Chromosome Segregation and Genomic Integrity in Human Epithelial Cells

“…In the analog-sensitive cell line, Plk1 as can be selectively inhibited by the bulky ATP analog 3-MB-PP1, resulting in loss of Plk1 functions with the expected phenotypes. Importantly, wild-type Plk1 is unaffected by 3-MB-PP1, allowing explicit controls for on-versus off-target effects (8,9). Moreover, BI-2536, an inhibitor of wild-type Plk1, does not affect activity of Plk1 as , allowing these two functional alleles to be orthogonally controlled independently with these chemicals (10).…”