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XB-ART-55316
J Cell Sci January 1, 2018; 132 (4):

PLK4 is a microtubule-associated protein that self-assembles promoting de novo MTOC formation.

Montenegro Gouveia S , Zitouni S , Kong D , Duarte P , Ferreira Gomes B , Sousa AL , Tranfield EM , Hyman A , Loncarek J , Bettencourt-Dias M .


Abstract
The centrosome is an important microtubule-organising centre (MTOC) in animal cells. It consists of two barrel-shaped structures, the centrioles, surrounded by the pericentriolar material (PCM), which nucleates microtubules. Centrosomes can form close to an existing structure (canonical duplication) or de novo How centrosomes form de novo is not known. The master driver of centrosome biogenesis, PLK4, is critical for the recruitment of several centriole components. Here, we investigate the beginning of centrosome biogenesis, taking advantage of Xenopus egg extracts, where PLK4 can induce de novo MTOC formation ( Eckerdt et al., 2011; Zitouni et al., 2016). Surprisingly, we observe that in vitro, PLK4 can self-assemble into condensates that recruit α- and β-tubulins. In Xenopus extracts, PLK4 assemblies additionally recruit STIL, a substrate of PLK4, and the microtubule nucleator γ-tubulin, forming acentriolar MTOCs de novo The assembly of these robust microtubule asters is independent of dynein, similar to what is found for centrosomes. We suggest a new mechanism of action for PLK4, where it forms a self-organising catalytic scaffold that recruits centriole components, PCM factors and α- and β-tubulins, leading to MTOC formation.This article has an associated First Person interview with the first author of the paper.

PubMed ID: 30237222
PMC ID: PMC6398482
Article link: J Cell Sci


Species referenced: Xenopus laevis
Genes referenced: dnai1 mapre3 mtor plk4 stil tub tuba4b tubg1
GO keywords: centrosome organization [+]


Article Images: [+] show captions
References [+] :
Arquint, STIL binding to Polo-box 3 of PLK4 regulates centriole duplication. 2016, Pubmed