The autoregulated instability of Polo-like kinase 4 limits centrosome duplication to once per cell cycle

Abstract

Centrioles organize the centrosome, and accurate control of their number is critical for the maintenance of genomic integrity. Centriole duplication occurs once per cell cycle and is controlled by Polo-like kinase 4 (Plk4). We showed previously that Plk4 phosphorylates itself to promote its degradation by the proteasome. Here we demonstrate that this autoregulated instability controls the abundance of endogenous Plk4. Preventing Plk4 autoregulation causes centrosome amplification, stabilization of p53, and loss of cell proliferation; moreover, suppression of p53 allows growth of cells carrying amplified centrosomes. Plk4 autoregulation thus guards against genome instability by limiting centrosome duplication to once per cell cycle.

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

“…We first used SRM to determine the absolute amounts of the above proteins in lysates prepared from different cells lines (Fig 2A and Table EV1). As expected (Holland et al , 2012), we found that Plk4 is a low abundance protein, ranging from 1,200 to 5,000 copies/cell in KE37 and U2OS cells, respectively. Considering that cultured human cells are estimated to harbor some 6–8 × 10 9 protein molecules per cell (Sims & Allbritton, 2007; Siwiak & Zielenkiewicz, 2013), this attests to the exquisite sensitivity of SRM and implies that we have detected one Plk4 polypeptide chain against a background of > 10 6 protein molecules.…”

The Centrosome and Its Duplication Cycle

“…If this system fails, the consequence is development of multiple centrioles both in Drosophila and human cells. Plk4 degradation first requires that Plk4 forms a homodimer through its carboxy-terminal coiledcoil region (Leung et al 2002;Habedanck et al 2005), where it is able to autophosphorylate a phosphodegron enabling the binding of SCF Slimb/bTrCP to promote its own destruction (Guderian et al 2010;Holland et al 2010Holland et al , 2012Sillibourne et al 2010). Consistently, the ZYG-1 kinase of C. elegans is also down-regulated by the Slimb/bTrCP homolog, LIN-23, and also a second F-box protein, SEL-10 (Peel et al 2012).…”

“…This is normally associated with stabilization of p53 and loss of cell proliferation. In the absence of p53, function cells carrying amplified centrosomes are able to proliferate (Holland et al 2012). The complexity of this regulative network is heightened by the recent report that Plk4 is directly phosphorylated and activated by stress-activated protein kinase kinase kinases (SAPKKKs) to promote centrosome duplication (Nakamura et al 2013).…”

The E3 ubiquitin ligase Mib1 regulates Plk4 and centriole biogenesis

“…Tight control of Plk4 levels is crucial, as its depletion leads to a gradual loss of centrioles and its overexpression to centriole amplification (Bettencourt-Dias et al, 2005;Habedanck et al, 2005;Kleylein-Sohn et al, 2007;Rodrigues-Martins et al, 2007). One important mechanism for controlling Plk4 abundance is based on the ability of Plk4 to dimerize and trans-autophosphorylate, which results in the generation of a phosphodegron for recognition by Skp, Cullin, F-box containing complex coanatining b-TrCP (SCF b-TrCP ), an E3 ligase, and subsequent degradation of Plk4 by the proteasome (Cunha-Ferreira et al, 2013;Cunha-Ferreira et al, 2009;Guderian et al, 2010;Holland et al, 2012;Holland et al, 2010;Klebba et al, 2013;Sillibourne et al, 2010). Other regulatory mechanisms are likely to exist, and a full understanding of Plk4 regulation is important, particularly in view of the frequent deregulation of this kinase in human cancers (Chng et al, 2008;Macmillan et al, 2001;Mason et al, 2014;van de Vijver et al, 2002) and the impact of Plk4 mutations on brain development and body growth (Martin et al, 2014).…”