Cell communication among the different cells which compound our body is an important factor during different biological processes, such as the embryonic development. Most of the cells of our body contain a non-motile primary cilium, formed by a microtubule-organized structure, which acts as an antenna for the cell. The membrane of this primary cilium contains huge amounts of different cell signaling receptors that transduce extracelullar signals, cominng from other cells, to inside the cell. However, how the primary cilium is formed and manteined remains still unclear.
Recently, some studies suggest that primary cilia might be regulated by a small GTPase called Ran. The classical function of Ran is to regulate the cytoplasmic/nuclear transport system. Moreover, Ran controls microtubule nucleation, stability and organization during mitosis resulting in the mitotic spindle formation. Since, the mitotic spindle and the cilium have different components in common, such as the fact that both are microtubule-based structures, we think that the cilium can be regulated by Ran as it occurs in the mitotic spindle.