A major challenge in the field is to integrate the highly detailed functional description of ribosome maturation into a three-dimensional vision of ribosome assembly and understand the structural remodeling of pre-ribosomal particles along their maturation path. Cryo-electron microscopy is the major technique available to reach this goal. In collaboration with Pr. Ulrike Kutay (ETH Zürich), we have developed an ambitious project to solve the structure of human pre-40S particles at various maturation stages by single particle analysis in cryo-electron microscopy. This project aims at understanding the structural dynamics of the pre-40S particles that underlies the assembly pathway.