HDAC6 is a unique cytoplasmic deacetylase capable of interacting with ubiquitin. Using a combination of biophysical, biochemical and biological approaches, we have characterized the ubiquitin-binding domain of HDAC6, named ZnF-UBP, and investigated its biological functions. These studies show that the three Zn ion-containing HDAC6 ZnF-UBP domain presents the highest known affinity for ubiquitin monomers and mediates the ability of HDAC6 to negatively control the cellular polyubiquitin chain turnover. We further show that HDAC6-interacting chaperone, p97/VCP, dissociates the HDAC6-ubiquitin complexes and counteracts the ability of HDAC6 to promote the accumulation of polyubiquitinated proteins. We propose that a finely tuned balance of HDAC6 and p97/VCP concentrations determines the fate of ubiquitinated misfolded proteins: p97/VCP would promote protein degradation and ubiquitin turnover, whereas HDAC6 would favour the accumulation of ubiquitinated protein aggregates and inclusion body formation.
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http://dx.doi.org/10.1038/sj.emboj.7601210 | DOI Listing |
Mol Cell Proteomics
January 2025
Department of Biology, Duke University, Durham, NC, 27708, USA. Electronic address:
Under stress conditions, cells reprogram their molecular machineries to mitigate damage and promote survival. Ubiquitin signaling is globally increased during oxidative stress, controlling protein fate and supporting stress defenses at several subcellular compartments. However, the rules driving subcellular ubiquitin localization to promote concerted response mechanisms remain understudied.
View Article and Find Full Text PDFMol Cell
January 2025
MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK. Electronic address:
Unassembled and partially assembled subunits of multi-protein complexes have emerged as major quality control clients, particularly under conditions of imbalanced gene expression such as stress, aging, and aneuploidy. The factors and mechanisms that eliminate such orphan subunits to maintain protein homeostasis are incompletely defined. Here, we show that the UBR4-KCMF1 ubiquitin ligase complex is required for the efficient degradation of multiple unrelated orphan subunits from the chaperonin, proteasome cap, proteasome core, and a protein targeting complex.
View Article and Find Full Text PDFCommun Biol
January 2025
Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Stalled ribosomes cause collisions, impair protein synthesis, and generate potentially harmful truncated polypeptides. Eukaryotic cells utilize the ribosome-associated quality control (RQC) and no-go mRNA decay (NGD) pathways to resolve these problems. In yeast, the E3 ubiquitin ligase Hel2 recognizes and polyubiquitinates disomes and trisomes at the 40S ribosomal protein Rps20/uS10, thereby priming ribosomes for further steps in the RQC/NGD pathways.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2025
Department of Molecular Biosciences, University of Texas, Austin, Texas 78712, United States.
The effectiveness of state-of-the-art cross-linking strategies and mass spectrometry (MS) detection was explored in an important biological context, namely, the ubiquitin-proteasome system, which is responsible for most of the regulated protein degradation in eukaryotic cells. The locations of possible binding sites on the 19S proteasome regulatory particle for Lys linked polyubiquitin chains were examined using cross-linking strategies and MS based detection by comparing two types of cross-linkers: a (bis)-sulfosuccinimidyl suberate (BS) and diethyl suberothioimidate (DEST). The well-established BS-based strategy produced 328 cross-linked peptides; however, no ubiquitin-19S cross-links were observed.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
Protein homeostasis is crucial for maintaining cardiomyocyte (CM) function. Disruption of proteostasis results in accumulation of protein aggregates causing cardiac pathologies such as hypertrophy, dilated cardiomyopathy (DCM), and heart failure. Here, we identify ubiquitin-specific peptidase 5 (USP5) as a critical determinant of protein quality control (PQC) in CM.
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