Mitotic Exit Function of Polo-like Kinase Cdc5 Is Dependent on Sequential Activation by Cdk1.

Jose-Antonio Rodriguez-Rodriguez,Ethel Queralt,Soraya Játiva,Yolanda Moyano

doi:10.1016/j.celrep.2016.04.079

Jose-Antonio Rodriguez-Rodriguez, Ethel Queralt + Show 2 more

Open Access

https://doi.org/10.1016/j.celrep.2016.04.079

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Abstract

To complete mitosis, Saccharomyces cerevisiae needs to activate the mitotic phosphatase Cdc14. Two pathways contribute to Cdc14 regulation: FEAR (Cdc14 early anaphase release) and MEN (mitotic exit network). Cdc5 polo-like kinase was found to be an important mitotic exit component. However, its specific role in mitotic exit regulation and its involvement in Cdc14 release remain unclear. Here, we provide insight into the mechanism by which Cdc5 contributes to the timely release of Cdc14. Our genetic and biochemical data indicate that Cdc5 acts in parallel with MEN during anaphase. This MEN-independent Cdc5 function requires active separase and activation by Cdk1-dependent phosphorylation. Cdk1 first phosphorylates Cdc5 to activate it in early anaphase, and then, in late anaphase, further phosphorylation of Cdc5 by Cdk1 is needed to promote its MEN-related functions.

Highlights

The phosphatase Cdc14 is a key regulatory protein of mitotic exit
Tem1 and Bub2-Bfa1 asymmetrically localize to the daughter spindle pole body (SPB) during mitosis, and their association with the SPBs is essential for mitotic exit (Bardin et al, 2000; Hu et al, 2001; Kim et al, 2012; Molk et al, 2004; Monje-Casas and Amon, 2009; Pereira et al, 2000, 2001; Valerio-Santiago and Monje-Casas, 2011)
Cdc5, along with Cdk1-Clb2, Contributes to the Release of Cdc14 The ectopic expression of Cdc5 has been shown to induce Cdc14 release and Net1 phosphorylation in metaphase (Manzoni et al, 2010; Visintin et al, 2003). This effect is not observed in arrested G1 phase cells (Figure S1A), indicating that the mechanism by which Cdc5 promotes Cdc14 release is dependent on the presence of some M phase components

Summary

Introduction

The phosphatase Cdc is a key regulatory protein of mitotic exit. Its principal function is to counteract Cdk activity by dephosphorylating Cdk targets (Jaspersen et al, 1999; Visintin et al, 1998). Tem promotes activation of the hippo-related kinase Cdc, which, in turn, activates the LATS-related MEN kinase Dbf2-Mob via phosphorylation (Mah et al, 2001; Mohl et al, 2009; Visintin and Amon, 2001; Visintin et al, 1999). This occurs in two steps: Cdc first creates phospho-docking sites on the MEN scaffold protein Nud, and Nud phosphorylation recruits Dbf2-Mob to SPBs, followed by Cdc15-dependent activation of Dbf2-Mob (Rock et al, 2013). The first burst of Cdc release induced by FEAR eventually dephosphorylates Cdc, which further activates Cdc (Jaspersen and Morgan, 2000; Menssen et al, 2001; Pereira et al, 2002; Stegmeier et al, 2002)

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