Huaiyu Sun

Crosstalk between the ubiquitin and SUMO pathways

Crosstalk between the SUMO and ubiquitin pathways

Conserved function of RNF4 family proteins in eukaryotes: targeting a ubiquitin ligase to SUMOylated proteins.

Published in The EMBO Journal

The function of small ubiquitin-like modifier (SUMO)-binding proteins is key to understanding how SUMOylation regulates cellular processes. We identified two related Schizosaccharomyces pombe proteins, Rfp1 and Rfp2, each having an N-terminal SUMO-interacting motif (SIM) and a C-terminal RING-finger domain. Genetic analysis shows that Rfp1 and Rfp2...

RING domain dimerization is essential for RNF4 function.

Published in Biochemical Journal

RNF4 [RING (really interesting new gene) finger protein 4] family ubiquitin ligases are RING E3 ligases that regulate the homoeostasis of SUMOylated proteins by promoting their ubiquitylation. In the present paper we report that the RING domain of RNF4 forms a stable dimer, and that dimerization is required for ubiquitin transfer. Our results sugge...

Poly-small ubiquitin-like modifier (PolySUMO)-binding proteins identified through a string search.

Published in Journal of Biological Chemistry

Polysumoylation is a crucial cellular response to stresses against genomic integrity or proteostasis. Like the small ubiquitin-like modifier (SUMO)-targeted ubiquitin ligase RNF4, proteins with clustered SUMO-interacting motifs (SIMs) can be important signal transducers downstream of polysumoylation. To identify novel polySUMO-binding proteins, we ...

Identification of small ubiquitin-like modifier substrates with diverse functions using the Xenopus egg extract system.

Published in Molecular & Cellular Proteomics

Post-translational modification by SUMO is a highly conserved pathway in eukaryotes that plays very important regulatory roles in many cellular processes. Deregulation of the SUMO pathway contributes to the development and progression of many diseases including cancer. Therefore, identifying additional SUMO substrates and studying how their cellula...

Multiple Arkadia/RNF111 structures coordinate its Polycomb body association and transcriptional control.

Published in Molecular and Cellular Biology

The RING domain protein Arkadia/RNF111 is a ubiquitin ligase in the transforming growth factor β (TGFβ) pathway. We previously identified Arkadia as a small ubiquitin-like modifier (SUMO)-binding protein with clustered SUMO-interacting motifs (SIMs) that together form a SUMO-binding domain (SBD). However, precisely how SUMO interaction contributes ...