Decoding the Ubiquitin signal into cellular response
This is the main theme of our research.
Ubiquitin (Ub) regulates numerous cellular pathways. But how is Ub attachment to a specific protein (ubiquitylation) actually recognized and decoded into a cellular response? Hundreds of Ub-receptors function to decipher the Ub code into specific responses. They do so by tethering Ub–binding domains (UBDs) to a response domain. Thus they exert the function they carry in their response domain onto ubiquitylated proteins they bind to.
Interestingly, Ub-receptors are themselves ubiquitylated. We proposed that this ubiquitylation inactivates their activity by blocking their UBD(s) (as shown in the cartoon).
Using our developed bacterial system for purification of ubiquitylated-proteins, we isolated large amounts of ubiquitylated-Ub-receptor sufficient for crystallization. Interestingly, our recent crystal structure of ubiquitylated-Ub-receptor provided a new outlook on the function of self-ubiquitylation.