The budding yeast Polo-like kinase Cdc5 is released from the nucleus during anaphase for timely mitotic exit

Abstract

Polo-like kinases are important regulators of multiple mitotic events; however, how Polo-like kinases are spatially and temporally regulated to perform their many tasks is not well understood. Here, we examined the subcellular localization of the budding yeast Polo-like kinase Cdc5 using a functional Cdc5-GFP protein expressed from the endogenous locus. In addition to the well-described localization of Cdc5 at the spindle pole bodies (SPBs) and the bud neck, we found that Cdc5-GFP accumulates in the nucleus in early mitosis but is released to the cytoplasm in late mitosis in a manner dependent on the Cdc14 phosphatase. This Cdc5 release from the nucleus is important for mitotic exit because artificial sequestration of Cdc5 in the nucleus by addition of a strong nuclear localization signal (NLS) resulted in mitotic exit defects. We identified a key cytoplasmic target of Cdc5 as Bfa1, an inhibitor of mitotic exit. Our study revealed a novel layer of Cdc5 regulation and suggests the existence of a possible coordination between Cdc5 and Cdc14 activity.

The budding yeast Polo-like kinase localizes to distinct populations at centrosomes during mitosis

“…This observation is in line with previous reports on Cdc5 SPB localization (Maekawa et al. , 2007; Botchkarev et al. , 2014).…”

“…Consistent with previous reports (Maekawa et al. , 2007; Botchkarev et al. , 2014), we show here that Cdc5 accumulates at both the mSPB and dSPB in metaphase and early anaphase but has a preference for the dSPB in late anaphase (Figure 7).…”

“…In support of this idea, cdc5-16 , which cannot localize to the SPBs in anaphase (Ratsima et al. , 2011; Botchkarev et al. , 2014), is defective in phosphorylation of Bfa1 (Ratsima et al.…”

Regulation of Mitotic Exit by Cell Cycle Checkpoints: Lessons From Saccharomyces cerevisiae

“…The multiple functions of Cdc5 in cell cycle control, as well as its fundamental role in the proficiency and interconnection between the different mitotic checkpoints, are timely and spatially coordinated by changes in the subcellular localization of the polo-like kinase throughout the cell cycle, which can be differentially found in the nucleus, the yeast centrosomes and in the bud neck at different cell cycle stages [161,[165][166][167]. Additionally, Cdc5 is also regulated through phosphorylation by different kinases, such as Cdc28/Cdk1 or PKA, which act as general upstream regulators of the Plk protein family [155].…”

The eukaryotic protein kinase superfamily of the necrotrophic fungal plant pathogen, Sclerotinia sclerotiorum

“…SS1G_05253 is similar to S. cerevisiae KCC4 and HSL1, which regulate entry into mitosis through phosphorylation of the ePK SWE1 (SS1G_04996; Other Group 01) and, in turn, phosphorylate the CDK CDC28 (SS1G_02296; CMGC Group) (Barral et al, 1999). SS1G_12333 is orthologous to S. cerevisiae KIN4, which is a key regulator of the spindle position checkpoint for cells exiting mitosis (Caydasi et al, 2010), whereas SS1G_04687 is orthologous to S. cerevisiae CDC5, which regulates Bfa1, an inhibitor of mitotic exit (Botchkarev et al, 2014). SS1G_01850 is orthologous to S. cerevisiae RAD53, which is involved in DNA damage checkpoint control (Usui and Petrini, 2014).…”