Fig. 1

Centrosome composition and duplication. a The centrosome is composed of a pair of centrioles, which consist of fibres connecting their proximal ends and PCM surrounding the centriole pair. Nine microtubule triplets, dubbed the A-, B-, and C-microtubules within each triplet, are present in the proximal region of centrioles. The C-microtubule is absent from the distal region. In the proximal region, the A-microtubule and the C-microtubule are connected by an A–C linker. Other striking features present in mature centrioles are the subdistal and distal appendages; b Cells in the G1 phase contain two centrioles termed the mother and daughter centrioles. Towards the G1-to-S transition, a procentriole starts to assemble. During the S and G2 phases, each procentriole remains engaged in this configuration with its parental centriole and elongates. Towards the end of G2, the flexible link between the two parental centrioles is severed, allowing the two centrosomes to separate and govern assembly of the bipolar mitotic spindle