Architecture of Human Translation Initiation Factor 3

Querol-Audí, Jordi; Sun, Chaomin; Vogan, Jacob M.; Smith, M. Duane; Gu, Yu; Cate, J.H.D.; Nogales, Eva

doi:10.1016/j.str.2013.04.002

Cited by 66 publications

(86 citation statements)

References 52 publications

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“…The PCI/MPN containing subunits form the "octamer" core that is similar to that found in the proteasome lid (Querol-Audi et al, 2013). The remaining subunits, b, d and g have RNA Recognition Motif (RRM) domains (Cuchalova et al, 2010); subunits b and i have WD40 domains and eIF3g has a zinc-binding domain Valasek, 2012;Voigts-Hoffmann et al, 2012;Hashem et al, 2013;Querol-Audi et al, 2013). Recent cryo-EM reconstructions of mammalian eIF3 and the 43S PIC indicate that eIF3 has five lobes and the PCI/MPN octamer forms the functional core of eIF3 (Siridechadilok et al, 2005;Khoshnevis et al, 2012;Hashem et al, 2013;Querol-Audi et al, 2013).…”

Section: Eif3mentioning

confidence: 74%

“…Higher eukaryotic eIF3 subunits a, c, e, and l all have PCI domains, k and m have structurally related winged helix domains (Zhou et al, 2005), and f and h have MPN domains. The PCI/MPN containing subunits form the "octamer" core that is similar to that found in the proteasome lid (Querol-Audi et al, 2013). The remaining subunits, b, d and g have RNA Recognition Motif (RRM) domains (Cuchalova et al, 2010); subunits b and i have WD40 domains and eIF3g has a zinc-binding domain Valasek, 2012;Voigts-Hoffmann et al, 2012;Hashem et al, 2013;Querol-Audi et al, 2013).…”

Section: Eif3mentioning

confidence: 85%

“…The remaining subunits, b, d and g have RNA Recognition Motif (RRM) domains (Cuchalova et al, 2010); subunits b and i have WD40 domains and eIF3g has a zinc-binding domain Valasek, 2012;Voigts-Hoffmann et al, 2012;Hashem et al, 2013;Querol-Audi et al, 2013). Recent cryo-EM reconstructions of mammalian eIF3 and the 43S PIC indicate that eIF3 has five lobes and the PCI/MPN octamer forms the functional core of eIF3 (Siridechadilok et al, 2005;Khoshnevis et al, 2012;Hashem et al, 2013;Querol-Audi et al, 2013). The placement of the eIF3 subunits and their contacts with the ribosome and other initiation factors awaits further structural data, but a picture is beginning to emerge at the molecular level (Wilson and Doudna Cate, 2012;Hashem et al, 2013;Liu et al, 2014).…”

Section: Eif3mentioning

confidence: 99%

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Mechanism of Cytoplasmic mRNA Translation

Browning

Bailey‐Serres

2015

The Arabidopsis Book

187

220

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Protein synthesis is a fundamental process in gene expression that depends upon the abundance and accessibility of the mRNA transcript as well as the activity of many protein and RNA-protein complexes. Here we focus on the intricate mechanics of mRNA translation in the cytoplasm of higher plants. This chapter includes an inventory of the plant translational apparatus and a detailed review of the translational processes of initiation, elongation, and termination. The majority of mechanistic studies of cytoplasmic translation have been carried out in yeast and mammalian systems. The factors and mechanisms of translation are for the most part conserved across eukaryotes; however, some distinctions are known to exist in plants. A comprehensive understanding of the complex translational apparatus and its regulation in plants is warranted, as the modulation of protein production is critical to development, environmental plasticity and biomass yield in diverse ecosystems and agricultural settings.

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Section: Eif3mentioning

confidence: 74%

Section: Eif3mentioning

confidence: 85%

Section: Eif3mentioning

confidence: 99%

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Mechanism of Cytoplasmic mRNA Translation

Browning

Bailey‐Serres

2015

The Arabidopsis Book

187

220

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“…The subunit eIF3j directly binds to the 40 S ribosomal RNA (68), and the subunits eIF3a, eIF3c, and eIF3d physically interact with the 5ЈUTRs of mRNAs (69 -72). Therefore, one or more of these subunits is likely to interact with TGF-␤ 5ЈUTRs, explaining why translation of TGF-␤s is not completely shut down in the absence of P311 (1).…”

Section: Discussionmentioning

confidence: 99%

Novel RNA-binding Protein P311 Binds Eukaryotic Translation Initiation Factor 3 Subunit b (eIF3b) to Promote Translation of Transforming Growth Factor β1-3 (TGF-β1-3)

Yue¹,

Lv²,

Meredith

et al. 2014

Journal of Biological Chemistry

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Background: P311 is a stimulator of TGF-␤1-3 translation, but its mechanism of action is unknown. Results: P311 binds eIF3b and the 5ЈUTRs of TGF-␤1-3 mRNAs. Thereby, P311 recruits TGF-␤1-3 mRNAs to the translation machinery. Conclusion: P311 is an RNA-binding protein that binds to eIF3b to stimulate TGF-␤1-3 translation. Significance: Our studies add a new level of complexity to TGF-␤ signaling regulation.

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“…The PCI subunits form a horseshoe-shaped structure and the MPN domains form a heterodimer, which are connected by a large helical bundle, to which all subunits contribute (13,17,18). Each of these eight subunits has paralogs in the COP9/signalosome (CSN) and the elongation initiation factor 3 (eIF3), which likely adopt a similar architecture (18)(19)(20)(21).The lid strengthens the interaction between the CP and RP (17) and deubiquitylates substrates before their processing by the AAA-ATPase module and the CP. Cleavage of polyubiquitin…”

mentioning

confidence: 99%

Crystal structure of the proteasomal deubiquitylation module Rpn8-Rpn11

Pathare

Nagy

Śledź

et al. 2014

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

120

131

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The ATP-dependent degradation of polyubiquitylated proteins by the 26S proteasome is essential for the maintenance of proteome stability and the regulation of a plethora of cellular processes. Degradation of substrates is preceded by the removal of polyubiquitin moieties through the isopeptidase activity of the subunit Rpn11. Here we describe three crystal structures of the heterodimer of the Mpr1-Pad1-N-terminal domains of Rpn8 and Rpn11, crystallized as a fusion protein in complex with a nanobody. This fusion protein exhibits modest deubiquitylation activity toward a model substrate. Full activation requires incorporation of Rpn11 into the 26S proteasome and is dependent on ATP hydrolysis, suggesting that substrate processing and polyubiquitin removal are coupled. Based on our structures, we propose that premature activation is prevented by the combined effects of low intrinsic ubiquitin affinity, an insertion segment acting as a physical barrier across the substrate access channel, and a conformationally unstable catalytic loop in Rpn11. The docking of the structure into the proteasome EM density revealed contacts of Rpn11 with ATPase subunits, which likely stabilize the active conformation and boost the affinity for the proximal ubiquitin moiety. The narrow space around the Rpn11 active site at the entrance to the ATPase ring pore is likely to prevent erroneous deubiquitylation of folded proteins.n eukaryotes, the ubiquitin (Ub) proteasome system (UPS) is responsible for the regulated degradation of proteins (1-5). The UPS plays a key role in the maintenance of protein homeostasis by removing misfolded or damaged proteins, which could impair cellular functions, and by removing proteins whose functions are no longer needed. Consequently, the UPS is critically involved in numerous cellular processes, including cell cycle progression, apoptosis, and DNA damage repair, and malfunctions of the system often result in disease.The 26S proteasome executes the degradation of substrates that are marked for destruction by the covalent attachment of polyubiquitin chains. It is a molecular machine of 2.5 MDa comprising two subcomplexes, the 20S core particle (CP) and one or two 19S regulatory particles (RPs), which associate with the ends of the cylinder-shaped CP (6-8). The recognition and recruitment of polyubiquitylated substrates, their deubiquitylation, ATP-dependent unfolding, and translocation into the core particle take place in the RP. The structurally and mechanistically well-characterized CP houses the proteolytic activities and sequesters them from the environment, thereby avoiding collateral damage (9).The RPs attach to the outer α-rings of the CP, which control access to the proteolytic chamber formed by the inner β-subunit rings (10). Recently, the molecular architecture of the 26S holocomplex was established using cryo-EM-based approaches (11,12), and a pseudoatomic model of the holocomplex was put forward (13). The RP is formed by two subcomplexes, known as the base and the lid, which assemble independent...

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Architecture of Human Translation Initiation Factor 3

Cited by 66 publications

References 52 publications

Mechanism of Cytoplasmic mRNA Translation

Mechanism of Cytoplasmic mRNA Translation

Novel RNA-binding Protein P311 Binds Eukaryotic Translation Initiation Factor 3 Subunit b (eIF3b) to Promote Translation of Transforming Growth Factor β1-3 (TGF-β1-3)

Crystal structure of the proteasomal deubiquitylation module Rpn8-Rpn11

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