Bremm Lab

SUMO Signaling Group



Head: Prof. Stefan Müller

Ubiquitin and Ubiquitin-like protein modification systems control a wide variety of cellular key processes. Our laboratory is studying mechanistic and functional aspects of the Ubiquitin-like SUMO system in mammalian cells. SUMO (Small Ubiquitin-like Modifier) functions as a post-translational modifier that is covalently attached to lysine residues of target proteins. Human cells express three SUMO forms, which are conjugated in a pathway that requires the E1 activating enzyme Aos1/Uba2, the E2 conjugating enzyme Ubc9 and in many cases involves E3 SUMO ligases.
SUMO modification is a dynamic, reversible process, in which the demodification of a given SUMO-conjugate is catalyzed by SUMO-specific proteases of the SENP family.
SUMO conjugation/deconjugation typically modulates protein-protein interactions thereby controlling cellular key pathways, including gene expression programs, ribosome biogenesis, mitotic progression or genomic integrity.
Signaling by SUMO generally relies on the recognition of a modified protein by a binding partner that contains a specialized SUMO binding module termed SUMO interaction motif (SIM).
However, a detailed understanding of SUMO function in most pathways is still incomplete because the relevant targets of modification and the corresponding SUMO-dependent binding partners have not been identified. In our work we therefore want to pinpoint the critical targets of SUMO in selected cellular pathways and aim to understand the dynamics of SUMO/SIM interactions.