Background: Ubiquitylation targets proteins for degradation by the 26S proteasome. Some yeast and plant ubiquitin ligases, including the highly conserved SCF (Skp1/Cul1/F-box protein) complex, have been shown to associate with proteasomes. We sought to characterize interactions between SCF complexes and proteasomes in mammalian cells.
Results: We found that the binding of SCF complexes to proteasomes is conserved in higher eukaryotes. The Cul1 subunit associated with both sub-complexes of the proteasome, and high molecular weight forms of Cul1 bound to the 19S proteasome. Cul1 is ubiquitylated in vivo. Ubiquitylation of Cul1 promotes its binding to the S5a subunit of the 19S sub-complex without affecting Cul1 stability.
Conclusion: The association of ubiquitylating enzymes with proteasomes may be an additional means to target ubiquitylated substrates for degradation.
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http://dx.doi.org/10.1186/1747-1028-1-5 | DOI Listing |
Cyclin F, a non-canonical member of the cyclin protein family, plays a critical role in regulating the precise transitions of cell-cycle events. Unlike canonical cyclins, which bind and activate cyclin-dependent kinases (CDKs), Cyclin F functions as a substrate receptor protein within the Skp1-Cullin-F box (SCF) E3 ubiquitin ligase complex, enabling the ubiquitylation of target proteins. The structural features that distinguish Cyclin F as a ligase adaptor and the mechanisms underlying its selective substrate recruitment over Cyclin A, which functions in complex with CDK2 at a similar time in the cell cycle, remain largely unexplored.
View Article and Find Full Text PDFACS Omega
January 2025
Laboratory of Glycoconjugate Chemistry, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia.
O-Protected oxacarbenium ions are key intermediates of glycosylation reactions. The knowledge of their conformational preferences is crucial for choosing the correct blocking group pattern to achieve the required stereochemical outcome. This article describes a computational study of several glucosyl oxacarbenium cations.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Department of Economics and Management, Russian University of Cooperation, 420034 Kazan, Russia.
The process of establishing relay protection and automation (RPA) settings for electric power systems (EPSs) entails complex calculations of operating modes. Traditionally, these calculations are based on symmetrical components, which require the building of equivalent circuits of various sequences. This approach can lead to errors both when identifying the operating modes and when modeling the RPA devices.
View Article and Find Full Text PDFPLoS Genet
January 2025
National Glycoengineering Research Center, Shandong University, Qingdao, China.
Protein ubiquitination is usually coupled with proteasomal degradation and is crucial in regulating protein quality. The E3 ubiquitin-protein ligase SCF (Skp1-Cullin-F-box) complex directly recognizes the target substrate via interaction between the F-box protein and the substrate. F-box protein is the determinant of substrate specificity.
View Article and Find Full Text PDFCell Rep
January 2025
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, Shandong Key Laboratory of Precision Molecular Crop Design and Breeding, School of Life Science, Shandong University, Qingdao, Shandong 266237, China. Electronic address:
Jasmonate (JA), a key plant hormone, regulates various aspects of plant development and stress responses, primarily through the degradation of canonical jasmonate-ZIM domain (JAZ) proteins by the SCF complex. While JAZ8, a non-canonical JAZ protein lacking the degron signal, has been shown to repress JA responses, the mechanism by which JA inhibits JAZ8 activity remains unclear. Here, we demonstrate that Arabidopsis ethylene response factor 114 (ERF114), ERF115, and ERF109 regulate JA signaling through interacting with JAZ8.
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