Regulation of the Distal Tip Complex Controls Centriole Length

Abstract

Cancer is one of the most prevalent and deadly diseases worldwide despite the development of an abundance of therapies in the last several decades. Recently, focus has turned to cancer prevention to help mitigate the morbidity of the disease and thus identification of mechanisms that initiate tumorigenesis is of utmost importance. Chromosomal instability is known to be a driver of tumorigenesis and creates vast diversity within the same tumor, allowing for selection and clonal expansion of cells with oncogenic karyotypes. Centrosome amplification is one of the main mechanisms that induces chromosomal instability and does so by creating aberrant attachments to chromosomes during mitosis which often leads to chromosome missegregation. Recent work has identified centriole elongation as a cause of centriole amplification through fragmentation and ectopic procentriole formation, however, how centrioles regulate their length is poorly understood. One proposed method involves antagonistic interactions between CP110, Cep97 and Klp10A at the distal end of centrioles (referred to as the Distal Tip Complex). Previous work in Drosophila has suggested that CP110 limits the centriolar microtubule depolymerizing activity of Klp10A, preventing over-shortening and maintaining the centriole at the correct length. However, how it does so mechanistically is unknown. Even less is known about the activity of centriolar protein Cep97 although previous work proposed it might have a stabilizing role on CP110. Using Drosophila Schneider 2 cells, we investigated the interaction of Cep97 and CP110. Our results suggest that Cep97, through a region in its C-terminal domain, binds and promotes the phosphorylation of CP110, bestowing stabilization.