Authors: Ana Pimenta-Marques; Tânia Perestrelo; Patrícia Rodrigues; Paulo Duarte; Mariana Faria; Mónica Bettencourt-Dias
Affiliation: Instituto Gulbenkian de Ciência
Keywords: a. cytoskeleton; b. oogenesis
An important feature for cell homeostasis is how structures such as different organelles are maintained in the cell. This is particularly relevant for organelles whose number and function are under a tight control, as deregulation of these properties has critical implications for the cell. This is the case of the centrosome. The centrosome is the main microtubule-organizing center of eukaryotic cells. This organelle is composed of two centrioles, surrounded by a multiprotein matrix called the pericentriolar
material (PCM) which is critical for microtubule nucleation.
Centrosomes are thought to be very stable and can persist over long periods of time. However, these structures can disappear in certain developmental stages and their numbers and structure can be deregulated in several diseases. Moreover, some centrosome components are quite dynamic. While a large body of knowledge has been produced regarding the biogenesis of these structures, little is known about how they are maintained. Our previous work showed that both POLO kinase and PCM are critical players in a centriole maintenance program which is shut off in the female germ-line to allow fertility. We have now investigated the players involved in this program, at the level of the centriole.
By studying centrosome stability in the female germline and in Drosophila cultured cells, we found that several centriole components play a role, amongst them the centriolar wall protein ANA1 has a very strong phenotype associated with the centrosome maintenance program. We then further show that the stability conferred by Polo and the PCM to centrosomes is dependent on ANA1, and that ectopic targeting of ANA1 can prevent centrosome loss in oogenesis.
Our work suggests that the PCM functions as a concentrator of components, in particular ANA1, which are required for centriole maintenance. We will discuss our data and how it provides a deeper understanding on the molecular mechanisms by which centriole stability is regulated.