Ana1 helps recruit Polo to centrioles to promote mitotic PCM assembly and centriole elongation.

Ines Alvarez-Rodrigo,Saroj Saurya,Jordan W Raff,Alan Wainman

doi:10.1242/jcs.258987

Abstract

ABSTRACTPolo kinase (PLK1 in mammals) is a master cell cycle regulator that is recruited to various subcellular structures, often by its polo-box domain (PBD), which binds to phosphorylated S-pS/pT motifs. Polo/PLK1 kinases have multiple functions at centrioles and centrosomes, and we have previously shown that in Drosophila phosphorylated Sas-4 initiates Polo recruitment to newly formed centrioles, while phosphorylated Spd-2 recruits Polo to the pericentriolar material (PCM) that assembles around mother centrioles in mitosis. Here, we show that Ana1 (Cep295 in humans) also helps to recruit Polo to mother centrioles in Drosophila. If Ana1-dependent Polo recruitment is impaired, mother centrioles can still duplicate, disengage from their daughters and form functional cilia, but they can no longer efficiently assemble mitotic PCM or elongate during G2. We conclude that Ana1 helps recruit Polo to mother centrioles to specifically promote mitotic centrosome assembly and centriole elongation in G2, but not centriole duplication, centriole disengagement or cilia assembly.This article has an associated First Person interview with the first author of the paper.

Highlights

Polo kinase (PLK1 in mammals) is an important cell cycle regulator (Pintard and Archambault, 2018)
A candidate screen for centriole proteins that help to recruit Polo to centrioles To identify proteins involved in recruiting Polo to the mother centriole we examined a small number of candidates that are important for centriole assembly and/or function in flies and that, like Polo, localise in a ring around the mother centriole: Sas-4, Asl, Cep135, Ana1 and PLP (Mennella et al, 2012; Fu and Glover, 2012; Fu et al, 2016; Saurya et al, 2016; Tian et al, 2021)
The polo-box domain (PBD) is required to efficiently target PLK1 to centrioles and centrosomes (Elia et al, 2003a,b; Hanisch et al, 2006; Jang et al, 2002; Lee et al, 1998; Seong et al, 2002; Song et al, 2000; Reynolds and Ohkura, 2003), and we previously uncovered the role of Spd-2 in recruiting Polo to the mitotic pericentriolar material (PCM) by mutating all 34 of the potential PBD-binding S-S/T motifs in Spd-2 to T-S/T

Summary

Introduction

Polo kinase (PLK1 in mammals) is an important cell cycle regulator (Pintard and Archambault, 2018). It is recruited to several locations in the cell – such as centrosomes, kinetochores and the cytokinesis apparatus – where it performs multiple functions (Colicino and Hehnly, 2018). PLK1 is usually recruited to these locations by its polo-box domain (PBD) (Lee et al, 1998; Liu et al, 2004; Reynolds and Ohkura, 2003), which binds to phosphorylated S-pS/pT motifs in target proteins (Elia et al, 2003a,b). PLK1 has several key functions at centrosomes. These organelles are important microtubule (MT) organising centres that form around a pair of centrioles (comprising a mother and daughter centriole) when

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