Monday 13 February 2006
Sumoylation is a highly dynamic process and its outcomes are extremely diverse, ranging from changes in localization to altered activity and, in some cases, stability of the modified protein.
SUMO (small ubiquitin-related modifier) proteins (as SUMO1) and ubiquitin (UBB) (MIM.191339) posttranslationally modify numerous cellular proteins and affect their metabolism and function.
However, unlike ubiquitination, which targets proteins for degradation, sumoylation participates in a number of cellular processes, such as nuclear transport, transcriptional regulation, apoptosis, and protein stability.
Many proteins that are important for regulated gene expression—including promoter-specific transcription factors, cofactors and chromatin-modifying enzymes—have been found to be reversibly modified by the small ubiquitin-related modifier, SUMO1.
Post-translational modification by SUMO1 has diverse effects on substrate activity, but, in most cases described to date, SUMOylation of transcriptional regulators correlates with inhibition of transcription.
The mechanisms by which SUMOylation regulates transcription and suggest that one consequence of SUMOylation is to promote the interaction of transcription factors with co-repressors.
Histone deacetylase co-repressors have been found to function as substrates, effectors, and regulators of SUMOylation, suggesting that complex crosstalk between acetylation and SUMOylation is important for gene regulation.
SUMO (small ubiquitin-related modifier)
reversible post-translational protein modifier
regulated SUMO-conjugation pathway
regulated SUMO-deconjugation pathway
Geiss-Friedlander R, Melchior F. Concepts in sumoylation: a decade on. Nat Rev Mol Cell Biol. 2007 Dec;8(12):947-56. PMID: 18000527
Gill G. Something about SUMO inhibits transcription. Curr Opin Genet Dev. 2005 Oct;15(5):536-41. PMID: 16095902
Nacerddine, K.; Lehembre, F.; Bhaumik, M.; Artus, J.; Cohen-Tannoudji, M.; Babinet, C.; Pandolfi, P. P.; Dejean, A. : The SUMO pathway is essential for nuclear integrity and chromosome segregation in mice. Dev. Cell 9: 769-779, 2005. PubMed ID : 16326389