Molecular mechanisms of multivesicular body biogenesis

Project leader: Hoflack

We want to understand the biogenesis of multi-vesicular bodies (MVBs), a process in which cargos destined to remain in outer endosomal membranes are sorted away from ubiquitinated cargos destined for degradation, in two distinct sorting steps requiring AP-3 and ESCRT, respectively. Using synthetic biology reconstituting MVB biogenesis coupled to quantitative mass spectrometry, we want to identify the protein networks regulating these processes. Using dedicated in vivo cell-based assays, we will validate the implication of selected candidates in this fundamental process of membrane maturation. Using Giant Unilamellar Vesicles (GUVs), we will illustrate their dynamic behavior during membrane maturation. Particularly, we want to investigate 1) how AP-3 and ESCRT sorting functions are coordinated and 2) how Rab5 to Rab7 conversion is timely regulated.