Centrioles are part of centrosomes and cilia, which are microtubule organising centres (MTOC) with diverse functions. Despite their stability, centrioles can disappear during differentiation, such as in oocytes, but little is known about the regulation of their structural integrity. Our previous research revealed that the pericentriolar material (PCM) that surrounds centrioles and its recruiter, Polo kinase, are downregulated in oogenesis and sufficient for maintaining both centrosome structural integrity and MTOC activity. We now show that the expression of specific components of the centriole cartwheel and wall, including ANA1/CEP295, is essential for maintaining centrosome integrity. We find that Polo kinase requires ANA1 to promote centriole stability in cultured cells and eggs. In addition, ANA1 expression prevents the loss of centrioles observed upon PCM-downregulation. However, the centrioles maintained by overexpressing and tethering ANA1 are inactive, unlike the MTOCs observed upon tethering Polo kinase. These findings demonstrate that several centriole components are needed to maintain centrosome structure. Our study also highlights that centrioles are more dynamic than previously believed, with their structural stability relying on the continuous expression of multiple components.
Synopsis: Centrosome integrity is critical for cell homeostasis. This study shows that different components of the centrosome, in particular ANA1/Cep295, are required for the maintenance of fully matured centrosomes.Components of the centriole cartwheel and wall, including ANA1/CEP295, maintain centrosome integrity.Polo kinase requires ANA1 to promote centriole stability in cultured cells and eggs.Overexpression of ANA1 prevents the loss of centrioles observed upon downregulation of the PCM in cells.Overexpression and tethering of ANA1 to centrioles prevents their normal loss during oogenesis.
Centrosome integrity is critical for cell homeostasis. This study shows that different components of the centrosome, in particular ANA1/Cep295, are required for the maintenance of fully matured centrosomes.