ATF5 is an essential protein in the centrosome

Abstract

The centrosome is the major microtubule (MT)-organizing center (MTOC) in animal cells. It comprises a pair of centrioles and the surrounding pericentriolar materials (PCM), and is duplicated once per cell cycle in a highly spatiotemporally regulated manner. Because of the intricate links between centrosomal functions, mitotic spindle assembly and cell division, defects in the centrosome structure and function often lead to malformation of mitotic spindles and genomic instabilities, which result in a range of human diseases including tumorigenesis, ciliopathy, microcephaly, and dwarfism.1 Previous studies indicated that the proximal end of the mother centriole plays instructive roles in the biogenesis of the PCM and the procentriole and that the PCM is essential for centriole stability. However, the molecules and the mechanism that control centriole-PCM interaction are poorly understood. In our recent study, published in the current issue of Cell,2 we provided evidence showing that the activating transcription factor 5 (ATF5) acts unexpectedly as an essential structural PCM protein that bridges the PCM and the proximal end of the mother centriole. By interacting with both pericentrin (PCNT) in the PCM and the polyglutamylated tubulin (PGT) at the proximal end of the mother centriole, ATF5 controls the formation of the PCM and the integrity of the centrioles in a cell cycle- and centriole age-dependent manner.(Fig. 1)