Ubiquitinated Proteins Activate the Proteasomal ATPases by Binding to Usp14 or Uch37 Homologs

Peth, Andreas; Kukushkin, Nikolay V.; Bossé, Marc; Goldberg, Alfred L.

doi:10.1074/jbc.m112.441907

Cited by 95 publications

(156 citation statements)

References 39 publications

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“…In a similar manner, the increased degradation of unfolded peptides by the 26S proteasome in the presence of ATP-γS (34) could be explained by a conformational change from the s1 state to the s3 state (14). In addition, binding of Ubp6 was reported to increase ATP hydrolysis (28). Our findings of the conformational change upon binding of Ubp6 to the OB domain of the ATPase imply alternations of the energy landscape of the 26S proteasome, which might lead to increased ATPase activity.…”

Section: Effects Of Ubp6 On 26s Proteasome Conformation and Catalyticmentioning

confidence: 77%

“…Independent of its own catalytic activity, Ubp6 also modulates the activity of the 26S proteasome. For example, it increases the hydrolysis rate of small peptides upon binding of ubiquitin conjugates or UbAld (27,28). Although initially interpreted as enhanced gate opening into the 20S CP (27,28), the most notable effect we observe upon binding of Ubp6-UbAld is a conformational change from the s1 to the s2 state.…”

Section: Effects Of Ubp6 On 26s Proteasome Conformation and Catalyticmentioning

confidence: 77%

“…For example, it increases the hydrolysis rate of small peptides upon binding of ubiquitin conjugates or UbAld (27,28). Although initially interpreted as enhanced gate opening into the 20S CP (27,28), the most notable effect we observe upon binding of Ubp6-UbAld is a conformational change from the s1 to the s2 state. A characteristic feature of the s2 state, as compared with the s1 state, is a better alignment of the channel axes of the CP and ATPase, suggesting that unfolded peptides can access the gated pore and catalytic cavity of the CP more easily.…”

Section: Effects Of Ubp6 On 26s Proteasome Conformation and Catalyticmentioning

confidence: 77%

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Structural characterization of the interaction of Ubp6 with the 26S proteasome

Aufderheide

Beck

Stengel

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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101

135

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In eukaryotic cells, the 26S proteasome is responsible for the regulated degradation of intracellular proteins. Several cofactors interact transiently with this large macromolecular machine and modulate its function. The deubiquitylating enzyme ubiquitin C-terminal hydrolase 6 [Ubp6; ubiquitin-specific protease (USP) 14 in mammals] is the most abundant proteasome-interacting protein and has multiple roles in regulating proteasome function. Here, we investigate the structural basis of the interaction between Ubp6 and the 26S proteasome in the presence and absence of the inhibitor ubiquitin aldehyde. To this end we have used single-particle electron cryomicroscopy in combination with cross-linking and mass spectrometry. Ubp6 binds to the regulatory particle non-ATPase (Rpn) 1 via its N-terminal ubiquitin-like domain, whereas its catalytic USP domain is positioned variably. Addition of ubiquitin aldehyde stabilizes the binding of the USP domain in a position where it bridges the proteasome subunits Rpn1 and the regulatory particle triple-A ATPase (Rpt) 1. The USP domain binds to Rpt1 in the immediate vicinity of the Ubp6 active site, which may effect its activation. The catalytic triad is positioned in proximity to the mouth of the ATPase module and to the deubiquitylating enzyme Rpn11, strongly implying their functional linkage. On the proteasome side, binding of Ubp6 favors conformational switching of the 26S proteasome into an intermediateenergy conformational state, in particular upon the addition of ubiquitin aldehyde. This modulation of the conformational space of the 26S proteasome by Ubp6 explains the effects of Ubp6 on the kinetics of proteasomal degradation.conformational switching | proteolysis | proteostasis | quality control D egradation of proteins that are misfolded, damaged, or no longer needed is an essential element of cellular homeostasis. In eukaryotic cells, the ubiquitin-proteasome system (UPS) is the major pathway for regulated protein degradation (1). Proteins that are processed by the UPS are marked for destruction by polyubiquitin chains, which are recognized as a degradation signal by the 26S proteasome.The 26S proteasome consists of the core particle (CP), which degrades substrates into short peptides, and one or two 19S regulatory particles (RP), which associate with the ends of the cylinder-shaped CP to recruit substrates and prepare them for degradation (2, 3). Although the structure of the CP has been known for more than two decades (4, 5), the molecular architecture of the RP was unraveled by cryo-electron microscope (EM)-based approaches only recently (6-9). It comprises six RP triple A (AAA) ATPases (Rpt), 1-6, and 13 RP non-ATPases (Rpn), 1-3, 5-13, and 15. Similar to AAA-ATPases in prokaryotic ATP-dependent proteases, the Rpts form a hexameric ring that binds to the ends of the CP and is responsible for substrate unfolding and translocation into the CP. Unlike their prokaryotic counterparts, the Rpts are surrounded by non-ATPases. Apart from Rpn1, all Rpns form a cohesive struct...

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Section: Effects Of Ubp6 On 26s Proteasome Conformation and Catalyticmentioning

confidence: 77%

Section: Effects Of Ubp6 On 26s Proteasome Conformation and Catalyticmentioning

confidence: 77%

Section: Effects Of Ubp6 On 26s Proteasome Conformation and Catalyticmentioning

confidence: 77%

See 1 more Smart Citation

Structural characterization of the interaction of Ubp6 with the 26S proteasome

Aufderheide

Beck

Stengel

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

101

135

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“…Binding of ubiquitin chains to USP14/Ubp6 or UCH37 opens the gate of the 20S channel, and in combination with an unfolded substrate domain stimulates proteasomal ATPase activity. Although this offers the possibility of coupling ubiquitin recycling with degradation, gate opening or ATPase stimulation does not require catalytic activity (197,198). Expression of catalytically inactive USP14/ Ubp6 has been shown to have either positive or negative effects on proteasomal degradative activity, and these observations remain to be fully reconciled (84,143,197).…”

Section: A Proteasomal Dubsmentioning

confidence: 80%

Deubiquitylases From Genes to Organism

Clague

Barsukov

Coulson

et al. 2013

Physiological Reviews

365

384

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Ubiquitylation is a major posttranslational modification that controls most complex aspects of cell physiology. It is reversed through the action of a large family of deubiquitylating enzymes (DUBs) that are emerging as attractive therapeutic targets for a number of disease conditions. Here, we provide a comprehensive analysis of the complement of human DUBs, indicating structural motifs, typical cellular copy numbers, and tissue expression profiles. We discuss the means by which specificity is achieved and how DUB activity may be regulated. Generically DUB catalytic activity may be used to 1) maintain free ubiquitin levels, 2) rescue proteins from ubiquitin-mediated degradation, and 3) control the dynamics of ubiquitin-mediated signaling events. Functional roles of individual DUBs from each of five subfamilies in specific cellular processes are highlighted with an emphasis on those linked to pathological conditions where the association is supported by whole organism models. We then specifically consider the role of DUBs associated with protein degradative machineries and the influence of specific DUBs upon expression of receptors and channels at the plasma membrane.

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“…The overall function of DUBs is to cleave ubiquitinlinked molecules after the C-terminus of the last residue of ubiquitin (Gly76), being essential to: (i) the maintenance of monomeric ubiquitin pool, either by cleaving the ubiquitin precursor or by trimming polyubiquitin chains; (ii) rescue proteins targeted for degradation, allowing the cell to adapt quickly to physiological changes, and (iii) prevent ubiquitinproteasome dependent protein degradation (Guterman and Glickman, 2004;Komander et al, 2009). Activation of the DUBs Usp14 and Uch37, either by polyubiquitin chains or their chemical mimetics, stimulates the 19S associated ATPases thereby opening the 20S closed gate, and thus promoting peptide hydrolysis (Peth et al, 2009(Peth et al, , 2013.…”

Section: Deubiquitinating Enzymesmentioning

confidence: 99%

Role of the ubiquitin–proteasome system in brain ischemia: Friend or foe?

Caldeira

Salazar

Curcio

et al. 2014

Progress in Neurobiology

113

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A B S T R A C TThe ubiquitin-proteasome system (UPS) is a catalytic machinery that targets numerous cellular proteins for degradation, thus being essential to control a wide range of basic cellular processes and cell survival. Degradation of intracellular proteins via the UPS is a tightly regulated process initiated by tagging a target protein with a specific ubiquitin chain. Neurons are particularly vulnerable to any change in protein composition, and therefore the UPS is a key regulator of neuronal physiology. Alterations in UPS activity may induce pathological responses, ultimately leading to neuronal cell death. Brain ischemia triggers a complex series of biochemical and molecular mechanisms, such as an inflammatory response, an exacerbated production of misfolded and oxidized proteins, due to oxidative stress, and the breakdown of cellular integrity mainly mediated by excitotoxic glutamatergic signaling. Brain ischemia also damages protein degradation pathways which, together with the overproduction of damaged proteins and consequent upregulation of ubiquitin-conjugated proteins, contribute to the accumulation of ubiquitincontaining proteinaceous deposits. Despite recent advances, the factors leading to deposition of such aggregates after cerebral ischemic injury remain poorly understood. This review discusses the current knowledge on the role of the UPS in brain function and the molecular mechanisms contributing to UPS dysfunction in brain ischemia with consequent accumulation of ubiquitin-containing proteins. Chemical inhibitors of the proteasome and small molecule inhibitors of deubiquitinating enzymes, which promote the degradation of proteins by the proteasome, were both shown to provide neuroprotection in brain ischemia, and this apparent contradiction is also discussed in this review. ß

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Ubiquitinated Proteins Activate the Proteasomal ATPases by Binding to Usp14 or Uch37 Homologs

Cited by 95 publications

References 39 publications

Structural characterization of the interaction of Ubp6 with the 26S proteasome

Structural characterization of the interaction of Ubp6 with the 26S proteasome

Deubiquitylases From Genes to Organism

Role of the ubiquitin–proteasome system in brain ischemia: Friend or foe?

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