Résumé : This thesis describes the work that I have carried out in the Laboratory of Neurophysiolgy at the Université Libre de Bruxelles, under the supervision of Prof. Serge Schiffmann, in collaboration with Prof. Stéphane Schurmans of Université of Liège.The work is divided in two distinct but related projects and the results section is thus divided into two main chapters. The results described are presented in the form of two manuscripts, the first chapter is named “Ciliary phosphoinositides regulation by INPP5E controls Shh signaling by allowing trafficking of Gpr161 in neural stem cells primary cilium”.The second is named “Regulation of phosphoinositides ciliary levels controls trafficking and ciliogenesis in ependymal cells”.Since both manuscripts are comprehensive regarding the results, and methods, these are inserted as such into the thesis.An expanded introduction to the field, placing the results into context, precedes these two chapters. An extended discussion section follows each chapter; it presents some elements of discussion not included in the manuscripts, the implications of the results and the scope for further research.