Polo 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.
