NEDD8 is a ubiquitin-like protein that controls vital biological events through its conjugation to cullin family members. Recently, we identified a negative regulator of the NEDD8 conjugation system, NUB1, which interacts with NEDD8 and down-regulates NEDD8 expression post-transcriptionally (Kito, K., Yeh, E. T. H., and Kamitani, T. (2001) J. Biol. Chem. 276, 20603-20609). Here, we show that NUB1 possesses a ubiquitin-like domain at the N-terminal region and binds to S5a of the 19 S proteasome activator (PA700). A GST pull-down assay revealed that the overexpression of NUB1 leads to a greater precipitation of NEDD8 conjugates with GST-S5a, suggesting that NUB1 might have an adaptor function between S5a and NEDD8. Furthermore, proteasome inhibitors completely block NUB1-mediated down-regulation of NEDD8 expression. These results suggest that NUB1 recruits NEDD8 and its conjugates to the proteasome for degradation, providing a direct functional link between the NEDD8 conjugation system and the proteasomal degradation pathway.
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http://dx.doi.org/10.1074/jbc.M108636200 | DOI Listing |
Clin Sci (Lond)
January 2025
Zhengzhou University First Affiliated Hospital, Zhengzhou, China.
Neddylation is a process of attaching neuronal precursor cell-expressed developmentally downregulated protein 8 (NEDD8) to substrates for the protein function modulation via enzymatic cascades involving NEDD8-activating enzyme (E1), NEDD8-conjugating enzyme (E2), and NEDD8 ligase (E3). Defective in cullin neddylation 1 (DCN1) serves as a co-E3 ligase, that can simultaneously bind E2 UBE2M and cullin proteins to stabilize the catalytic center of the Cullin-Ring E3 ligase (CRL) complex, thereby promoting cullin neddylation. Neddylation is reported to be activated in diverse human diseases, and inhibition of protein neddylation has been regarded as a promising anticancer therapy.
View Article and Find Full Text PDFEMBO J
January 2025
Cancer Institute, The Second Affiliated Hospital, Zhejiang University School of Medicine, 310009, Hangzhou, China.
Small GTPase RHEB is a well-known mTORC1 activator, whereas neddylation modifies cullins and non-cullin substrates to regulate their activity, subcellular localization and stability. Whether and how RHEB is subjected to neddylation modification remains unknown. Here, we report that RHEB is a substrate of NEDD8-conjugating E2 enzyme UBE2F.
View Article and Find Full Text PDFCells
October 2024
Departments of Physiology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA.
The ongoing obesity epidemic has raised awareness of the complex physiology of adipose tissue. Abnormal adipocyte differentiation results in the development of systemic metabolic disorders such as insulin resistance and diabetes. The conjugation of NEDD8 (neural precursor cell expressed, developmentally downregulated 8) to target protein, termed neddylation, has been shown to mediate adipogenesis.
View Article and Find Full Text PDFExp Mol Med
October 2024
Department of Pharmacology, Chonnam National University Medical School, Hwasun, Jeollanamdo, Republic of Korea.
Vascular calcification (VC) refers to the accumulation of mineral deposits on the walls of arteries and veins, and it is closely associated with increased mortality in cardiovascular disease patients, particularly among high-risk patients with diabetes and chronic kidney disease (CKD). Neuronal precursor cell-expressed developmentally downregulated protein 8 (NEDD8) is a ubiquitin-like protein that plays a pivotal role in various cellular functions, primarily through its conjugation to target proteins and subsequent relay of biological signals. However, the role of NEDDylation in VC has not been investigated.
View Article and Find Full Text PDFTrends Biochem Sci
December 2024
Institute of Biotechnology and Biomedicine, Autonomous University of Barcelona, 08193 Bellaterra, Spain; Department of Biochemistry and Molecular Biology, Autonomous University of Barcelona, 08193 Bellaterra, Spain. Electronic address:
Ubiquitin (Ub) and ubiquitin-like (UbL) modifications are critical regulators of multiple cellular processes in eukaryotes. These modifications are dynamically controlled by proteases that balance conjugation and deconjugation. In eukaryotes, these proteases include deubiquitinases (DUBs), mostly belonging to the CA-clan of cysteine proteases, and ubiquitin-like proteases (ULPs), belonging to the CE-clan proteases.
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