Centrioles are required to assemble centrosomes for cell division and cilia for motility
and signalling. New centrioles assemble perpendicularly to pre-existing ones in G1-S
and elongate throughout S and G2. Fully elongated daughter centrioles are converted
into centrosomes during mitosis to be able to duplicate and organize pericentriolar
material in the next cell cycle. Here we show that centriole-to-centrosome conversion
requires sequential loading of Cep135, Ana1 (Cep295) and Asterless (Cep152) onto daughter
centrioles during mitotic progression in both Drosophila melanogaster and human. This
generates a molecular network spanning from the inner- to outermost parts of the centriole.
Ana1 forms a molecular strut within the network, and its essential role can be substituted
by an engineered fragment providing an alternative linkage between Asterless and Cep135.
This conserved architectural framework is essential for loading Asterless or Cep152,
the partner of the master regulator of centriole duplication, Plk4. Our study thus
uncovers the molecular basis for centriole-to-centrosome conversion that renders daughter
centrioles competent for motherhood.
