Sara Sigismund (»Add to Infobox)

Researcher Pier Paolo Di Fiore's Group Academic: IFOM- FIRC Institute of Molecular Oncology, Milan Phone:  +39 2 574303301 Email:  sara.sigismundifom-ieo-campus.it

General description: My research concerns the role of cargo monoubiquitination at the initial step of internalization, how this is regulated and how it is recognized by the trafficking machinery at the level of the cell surface. Recent studies from our group showed that monoubiquitination directs the EGFR to non-clathrin/raft-dependent endocytosis. This is mediated by the action of proteins harbouring ubiquitin-binding domains, eps15, eps15R and epsin, which couple the ubiquitinated cargo to the raft pathway. Moreover, we have found differential recruitment of the EGFR into clathrin-dependent or -independent endocytosis as a function of EGF concentration, and this correlates with the ubiquitination status of the receptor. Role in RUBICON: My studies focus on: The molecular mechanism regulating receptor ubiquitination in response to EGF concentration. How ubiquitin mediates internalization through non-clathrin/raft endocytosis and which is the molecular machinery involved downstream of receptor ubiquitination. The functional meaning of clathrin-dependent and -independent internalization routes. Which is the fate of the receptor internalized via the two pathways?