Posttranslational modification with the small ubiquitin-related modifier SUMO depends on the sequential activities of E1, E2, and E3 enzymes. While regulation by E3 ligases and SUMO proteases is well understood, current knowledge of E2 regulation is very limited. Here, we describe modification of the budding yeast E2 enzyme Ubc9 by sumoylation (Ubc9(*)SUMO). Although less than 1% of Ubc9 is sumoylated at Lys153 at steady state, a sumoylation-deficient mutant showed significantly reduced meiotic SUMO conjugates and abrogates synaptonemal complex formation. Biochemical analysis revealed that Ubc9(*)SUMO is severely impaired in its classical activity but promoted SUMO chain assembly in the presence of Ubc9. Ubc9(*)SUMO cooperates with charged Ubc9 (Ubc9~SUMO) by noncovalent backside SUMO binding and by positioning the donor SUMO for optimal transfer. Thus, sumoylation of Ubc9 converts an active enzyme into a cofactor and reveals a mechanism for E2 regulation that orchestrates catalytic (Ubc9~SUMO) and noncatalytic (Ubc9(*)SUMO) functions of Ubc9.
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http://dx.doi.org/10.1016/j.molcel.2013.03.027 | DOI Listing |
Microorganisms
December 2024
Program in Public Health, School of Medicine, University of California, Irvine, CA 92617, USA.
, a major vector of dengue virus (DENV), has a global distribution. Identifying the key components of the ubiquitin system of essential for the replication of viruses could help identify targets for developing broad-spectrum antiviral strategies. This study explores the interaction between E2 ubiquitin-conjugating enzymes (Ubc9) and DENV-2 proteins (NS1, NS5, and E) using cell culture and mosquito models.
View Article and Find Full Text PDFPhysiology (Bethesda)
March 2025
Department of Pharmaceutical Sciences and the Center for Drug Discovery, The School of Pharmacy and Pharmaceutical SciencesBouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, United States.
The small ubiquitin-like modifier (SUMO) protein pathway governs a panoply of vital biological processes including cell death, proliferation, differentiation, metabolism, and signal transduction by diversifying the functions, half-lives, and partnerships of target proteins in situ. More recently, SUMOylation has emerged as a key regulator of ion homeostasis and excitability across multiple tissues due to the regulation of a plethora of ion channels expressed in a range of tissue subtypes. Altogether, the balance of SUMOylation states among relevant ion channels can result in graded biophysical effects that tune excitability and contribute to a range of disease states including cardiac arrhythmia, epilepsy, pain transmission, and inflammation.
View Article and Find Full Text PDFMetabolites
October 2024
Laboratory of Marine Biochemistry and Ecotoxicology, Department of Earth and Marine Sciences DiSTeM, University of Palermo, Via G. Barlotta 4, 91100 Trapani, Italy.
Nat Commun
October 2024
Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School, Singapore, Singapore.
A delicate balance between neural stem cell (NSC) quiescence and proliferation is important for adult neurogenesis and homeostasis. Small ubiquitin-related modifier (SUMO)-dependent post-translational modifications cause rapid and reversible changes in protein functions. However, the role of the SUMO pathway during NSC reactivation and brain development is not established.
View Article and Find Full Text PDFInt J Biochem Cell Biol
November 2024
Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan. Electronic address:
Dysregulated protein homeostasis, characterized by abnormal protein accumulation and aggregation, is a key contributor to the progression of neurodegenerative disorders such as Huntington's disease and spinocerebellar ataxia type 3 (SCA3). Previous studies have identified PIAS1 gene variants in patients with late-onset SCA3 and Huntington's disease. This study aims to elucidate the role of PIAS1 and its S510G variant in modulating the pathogenic mechanisms of SCA3.
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