Structural Basis for Specific Recognition of Rpt1p, an ATPase Subunit of 26 S Proteasome, by Proteasome-dedicated Chaperone Hsm3p

Takagi, Kenji; Kim, Sang Woo; Yukii, Haruka; Ueno, Mika; Morishita, Ryo; Endo, Yaeta; Kato, Koichi; Tanaka, Keiji; Saeki, Yasushi; Mizushima, Tsunehiro

doi:10.1074/jbc.m112.345876

Cited by 31 publications

(39 citation statements)

References 42 publications

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“…Chaperone binding is thus hypothesized to occlude contacts between the Rpt tail and its cognate a pocket, thus minimizing the formation of premature or incorrect RP-CP contacts ). The RP chaperones Hsm3, Nas6, and Rpn14 do not bind the Rpt tail, only the proximal C domain Takagi et al 2012). Thus, they may occlude the tail by virtue of the proximity of the C domain to the tail.…”

Section: Rp Assemblymentioning

confidence: 99%

The Ubiquitin–Proteasome System of Saccharomyces cerevisiae

et al. 2012

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Protein modifications provide cells with exquisite temporal and spatial control of protein function. Ubiquitin is among the most important modifiers, serving both to target hundreds of proteins for rapid degradation by the proteasome, and as a dynamic signaling agent that regulates the function of covalently bound proteins. The diverse effects of ubiquitylation reflect the assembly of structurally distinct ubiquitin chains on target proteins. The resulting ubiquitin code is interpreted by an extensive family of ubiquitin receptors. Here we review the components of this regulatory network and its effects throughout the cell.

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Section: Rp Assemblymentioning

confidence: 99%

The Ubiquitin–Proteasome System of Saccharomyces cerevisiae

et al. 2012

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“…The subunits of the RP base can be expressed in E. coli as soluble proteins. The reconstituted RP base confers an equivalent activity to the 26S proteasomes than the endogenous complex [98,99].…”

Section: Molecular Composition Of the Rp Basementioning

confidence: 99%

Proteasome assembly

Enenkel

2014

Cell. Mol. Life Sci.

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In eukaryotic cells, proteasomes are highly conserved protease complexes and eliminate unwanted proteins which are marked by poly-ubiquitin chains for degradation. The 26S proteasome consists of the proteolytic core particle, the 20S proteasome, and the 19S regulatory particle, which are composed of 14 and 19 different subunits, respectively. Proteasomes are the second-most abundant protein complexes and are continuously assembled from inactive precursor complexes in proliferating cells. The modular concept of proteasome assembly was recognized in prokaryotic ancestors and applies to eukaryotic successors. The efficiency and fidelity of eukaryotic proteasome assembly is achieved by several proteasome-dedicated chaperones that initiate subunit incorporation and control the quality of proteasome assemblies by transiently interacting with proteasome precursors. It is important to understand the mechanism of proteasome assembly as the proteasome has key functions in the turnover of short-lived proteins regulating diverse biological processes.

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“…Moreover, the crystal structure of RAC4 revealed that it has a C-shaped structure consisting of 11 HEAT repeats. 38 The structure of the RAC4−Rpt1−C complex revealed that the interacting surface between RAC4 and Rpt1 is a hydrophobic core and complementary charged surface. Mutations in the RAC4−Rpt1 surface resulted in an assembly defect in the 26S proteasome.…”

Section: Assemblymentioning

confidence: 99%

The Proteasome: From Basic Mechanisms to Emerging Roles

Tanaka

2013

Keio J. Med.

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The proteasome is a sophisticated, 2.5-MDa, multisubunit complex that contains a catalytic core particle (CP) and two terminal regulatory particles (RPs); the RPs associate with the termini of the central CP at opposite orientations. The CP consists of four axially stacked heptameric rings (two outer α-rings and two inner β-rings), which are made up of seven structurally related, but not identical, α and β subunits. The CP contains catalytic threonine residues (in β1, β2, and β5 with caspase-like, trypsin-like, and chymotrypsin-like activities, respectively) on the surface of the chamber formed by two abutting β-rings. The RP recognizes polyubiquitylated substrate proteins and unfolds and translocates these proteins to the interior of the CP for degradation. The RP comprises 19 different subunits, which are thought to form two subcomplexes called the lid and the base. One longstanding question is how the complex structure of the proteasome is organized with high fidelity. Recently, we proposed a novel assembly mechanism that is assisted by multiple proteasome-dedicated chaperones. In addition, we discovered two immuno-type proteasomes, the immunoproteasome and the thymoproteasome, whose catalytic subunits are replaced by homologous counterparts. These two isoforms perform specialized functions that help discriminate self from non-self in cell-mediated immunity (i.e., they function as enzymes that process intracellular antigens for cytotoxic T lymphocyte responses and thymic positive selection). Moreover, emerging evidence suggests that the proteasome is crucially involved in the pathophysiology of various intractable diseases that are increasing in today's aging society.

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Structural Basis for Specific Recognition of Rpt1p, an ATPase Subunit of 26 S Proteasome, by Proteasome-dedicated Chaperone Hsm3p

Cited by 31 publications

References 42 publications

The Ubiquitin–Proteasome System of Saccharomyces cerevisiae

The Ubiquitin–Proteasome System of Saccharomyces cerevisiae

Proteasome assembly

The Proteasome: From Basic Mechanisms to Emerging Roles

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