The centrosome is a non-membranous subcellular structure composed of a mother and daughter centriole. The mother centriole function as the assembly point for the primary cilium, a microtubule-based sensory organelle, which is involved in signal transduction.

With Mother's day around the world in May, we take this as an opportunity to have a closer look inside the cell and at the small subcellular structure that plays the role of a mother. The non-membranous centrosome located close to the nucleus is composed of an older, mature mother centriole and a newly formed daughter centriole. Both centrioles are essential during the cell division, because they are required for assembling the spindle apparatus. But outside the cell cycle, the mother centriole has additional functions, for example it forms the basal body for cilia. Functional differences between the centrioles are the results from an asymmetrical localization of proteins to the mother and daughter centriole. Image-based approaches like the ICC-IF used in the HPA Cell Atlas can help to identify proteins that preferential localize to only a single centriole, such as Centrosomal protein of 19 kDa encoded by the CEP19 gene, which is an marker for the mother centriole (Jacobsen et al). CEP19 is involved in the early steps in cilia formation by recruiting material for the initial cilium assembly to the mother centriole (Mojarad et al). While cilia are often associated with movement and only detected on specialised cell types, nearly all human cells have a single primary cilium on their surface. Primary cilia are microtubule-based sensory organelles and are involved in different pathways. For example, primary cilia regulate the activity of the hedgehog pathway, which plays a crucial role in the development of organs and tissues from early embryonic stages (Goetz et al).

A list of proteins that locate to the centrosome (both mother and daughter centriole) can be found here.

Peter Thul