Crystal structure of the 80S yeast ribosome

Jenner, L.; Melnikov, Sergey; Loubresse, Nicolas Garreau de; Ben-Shem, Adam; Iskakova, Madina; Urzhumtsev, Alexandre; Meškauskas, Arturas; Dinman, Jonathan D.; Yusupova, G.; Yusupov, Marat

doi:10.1016/j.sbi.2012.07.013

Cited by 129 publications

(114 citation statements)

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“…Figure 2C). Contrary to the relatively simple 40S assembly route, which proceeds along the sequential, 5 0 -to-3 0 -oriented folding of its four distinct 3D domains, 60S assembly appears more complex as its six secondary-structure rRNA domains are elaborately intertwined in the mature 60S ribosome [2,4]. Moreover, evidence gathered over the past 15 years has revealed that LSU assembly occurs within several distinct and successive pre-60S intermediates of partially overlapping composition (Figure 2).…”

Section: Final Maturation Of Pre-40s Particlesmentioning

confidence: 98%

“…Despite our detailed knowledge of the pre-rRNA processing pathway in yeast and human cells [7,63], the enzymes that cleave the pre-rRNA at sites A 0 , A 1 , and A 2 have not yet been unambiguously assigned. While all three cleavages depend on the U3 snoRNP, processing at sites A 1 and A 2 appears to be coupled and occurs independently of A 0 cleavage [7].…”

Section: Dismantling Of the 90s Preribosome Releases An Early Pre-40smentioning

confidence: 99%

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A Puzzle of Life: Crafting Ribosomal Subunits

Kressler

Hurt

Baßler

2017

Trends in Biochemical Sciences

164

127

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The biogenesis of eukaryotic ribosomes is a complicated process during which the transcription, modification, folding, and processing of the rRNA is coupled with the ordered assembly of $80 ribosomal proteins (r-proteins). Ribosome synthesis is catalyzed and coordinated by more than 200 biogenesis factors as the preribosomal subunits acquire maturity on their path from the nucleolus to the cytoplasm. Several biogenesis factors also interconnect the progression of ribosome assembly with quality control of important domains, ensuring that only functional subunits engage in translation. With the recent visualization of several assembly intermediates by cryoelectron microscopy (cryo-EM), a structural view of ribosome assembly begins to emerge. In this review we integrate these first structural insights into an updated overview of the consecutive ribosome assembly steps. Synopsis of Eukaryotic Ribosome AssemblyRibosomes are the molecular machines that translate the genetic information from the intermediary mRNA templates into proteins [1]. Eukaryotic 80S ribosomes comprise two unequal subunits that contain four different rRNAs and around 80 r-proteins ( Figure 1). The small 40S subunit (SSU) comprises the 18S rRNA and 33 r-proteins (referred to as RPS or S). The large 60S subunit (LSU) comprises the 25S/28S, 5.8S, and 5S rRNA and, in most eukaryotic species, 47 r-proteins (RPL or L); a notable exception is budding yeasts, which lack eL28The act of building a ribosome begins in the nucleolus, where the ribosomal DNA (rDNA) is transcribed into a long pre-rRNA precursor (35S pre-rRNA in yeast) and involves the ordered assembly of the r-proteins with the pre-rRNA, which is concomitantly processed into the mature rRNA species [5][6][7][8] (Figure 1 and Box 1). These assembly and processing events are tightly coupled and occur within preribosomal particles (see Glossary) that travel, as maturation progresses, from the nucleus across nuclear pore complexes (NPCs) to the cytoplasm, where they are ultimately converted into translation-competent ribosomal subunits [5,[9][10][11][12][13] (Figure 2, Key Figure). Given the gargantuan complexity of this process, it is unsurprising that the assembly of eukaryotic ribosomes strictly requires the assistance of a plethora (>200) of mostly essential ribosome biogenesis factors, which are also called trans-acting or assembly factors [5,14,15].Our current knowledge has been mainly obtained by studying ribosome biogenesis in the yeast Saccharomyces cerevisiae. Research conducted in the 1970s defined the r-protein composition of ribosomes, revealed the major pre-rRNA processing intermediates, and uncovered the existence of the 90S, 43S, and 66S preribosomal particles. The following 25 years witnessed the identification of numerous biogenesis factors and attributed functional roles TrendsCryoelectron microscopy analyses of the 90S preribosome show that the biogenesis factors create a casting mold that encloses the nascent pre-40S subunit.Structures of nuclear pre-60S particles reveal that a...

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Section: Final Maturation Of Pre-40s Particlesmentioning

confidence: 98%

Section: Dismantling Of the 90s Preribosome Releases An Early Pre-40smentioning

confidence: 99%

A Puzzle of Life: Crafting Ribosomal Subunits

Kressler

Hurt

Baßler

2017

Trends in Biochemical Sciences

164

127

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“…Tif6 is required for 60S ribosome biogenesis (17), but it has not been found to be involved in translation initiation (18). The protein structures of Tif6/eIF6 (19) free and in complex with the 60S subunit have been determined, and the major interaction site is the C terminus of Rpl23 (20) (Rpl23 is called uL14 in the new nomenclature (21)). The binding of Tif6 on the 60S subunits blocks association between 60S and 40S subunits by preventing the formation of an intersubunit bridge (22).…”

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confidence: 99%

Bcp1 Is the Nuclear Chaperone of Rpl23 in Saccharomyces cerevisiae

Ting

Johnson

et al. 2017

Journal of Biological Chemistry

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Edited by Linda SpremulliEukaryotic ribosomes are composed of rRNAs and ribosomal proteins. Ribosomal proteins are translated in the cytoplasm and imported into the nucleus for assembly with the rRNAs. It has been shown that chaperones or karyopherins responsible for import can maintain the stability of ribosomal proteins by neutralizing unfavorable positive charges and thus facilitate their transports. Among 79 ribosomal proteins in yeast, only a few are identified with specific chaperones. Besides the classic role in maintaining protein stability, chaperones have additional roles in transport, chaperoning the assembly site, and dissociation of ribosomal proteins from karyopherins. Bcp1 has been shown to be necessary for the export of Mss4, a phosphatidylinositol 4-phosphate 5-kinase, and required for ribosome biogenesis. However, its specific function in ribosome biogenesis has not been described. Here, we show that Bcp1 dissociates Rpl23 from the karyopherins and associates with Rpl23 afterward. Loss of Bcp1 causes instability of Rpl23 and deficiency of 60S subunits. In summary, Bcp1 is a novel 60S biogenesis factor via chaperoning Rpl23 in the nucleus.The ribosome is a large macromolecular complex responsible for decoding cellular genetic information into proteins. There are two ribosomal subunits; in the eukaryotes, they are the (60S) large subunit and the small (40S) subunit, each composed of both rRNAs and ribosomal proteins. In eukaryotic cells, the assembly of ribosomes occurs in the nucleolus, a subcompartment of the nucleus devoted to ribosome biogenesis. rRNAs are transcribed by RNA polymerase I and III, and the initial assembly and processing events occur co-transcriptionally. The mRNAs of ribosomal proteins are transcribed in the nucleus by RNA polymerase II and translated in the cytoplasm. Consequently, the ribosomal proteins must be imported into the nucleus for assembly with the rRNAs. After ribosome assemblies have achieved a certain stage of maturation, export factors are loaded to direct these huge complexes to cross the nuclear membrane through the nuclear pore complexes (1-6). In the cytoplasm, ribosomes undergo additional steps in the maturation process; the trans-acting factors that are exported with nascent ribosomal subunits need to be stripped off, additional ribosomal proteins are added, and in the case of the 40S subunit, the final rRNA processing occurs (7,8). The synthesis of ribosomes requires the coordination of many non-ribosomal trans-acting factors at different stages for this pathway to be completed. About 200 trans-acting factors are involved in rRNA processing, rRNA folding, protein loading, and export. To date, more trans-acting factors have continued to be identified (7, 9, 10).BCP1 is an essential gene involved in the export of Mss4 (11), a phosphatidylinositol (PI) 2 4-phosphate 5-kinase that catalyzes the phosphorylation of PI4-phosphate and acts with the PI4-kinase, Stt4p, at the plasma membrane to generate PI4,5P 2 (12, 13). Phosphoinositols are critical small signal...

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“…In this study, we addressed the functional connections among Puf6, Loc1, and ribosomal protein 43 (Rpl43 or L43e in newer nomenclature (18)). Whereas previous studies of Puf6 and Loc1 functions have been focused on their roles in the asymmetric distribution of ASH1 mRNA in yeast, their roles in 60S biogenesis have not been clearly elucidated.…”

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confidence: 99%

The Roles of Puf6 and Loc1 in 60S Biogenesis Are Interdependent, and Both Are Required for Efficient Accommodation of Rpl43

Yang

Ting

Liang

et al. 2016

Journal of Biological Chemistry

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Puf6 and Loc1 have two important functional roles in the cells, asymmetric mRNA distribution and ribosome biogenesis. Puf6 and Loc1 are localized predominantly in the nucleolus. They bind ASH1 mRNA, repress its translation, and facilitate the transport to the daughter cells. Asymmetric mRNA distribution is important for cell differentiation. Besides their roles in mRNA localization, Puf6 and Loc1 have been shown to be involved in 60S biogenesis. In puf6⌬ or loc1⌬ cells, pre-rRNA processing and 60S export are impaired and 60S subunits are underaccumulated. The functional studies of Puf6 and Loc1 have been focused on ASH1 mRNA pathway, but their roles in 60S biogenesis are still not clear. In this study, we found that Puf6 and Loc1 interact directly with each other and both proteins interact with the ribosomal protein Rpl43 (L43e). Notably, the roles of Puf6 and Loc1 in 60S biogenesis are interdependent, and both are required for efficient accommodation of Rpl43. Loc1 is further required to maintain the protein level of Rpl43. Additionally, the recruitment of Rpl43 is required for the release of Puf6 and Loc1. We propose that Puf6 and Loc1 facilitate Rpl43 loading and are sequentially released from 60S after incorporation of Rpl43 into ribosomes in yeast.Almost every process in a cell is mediated by proteins, the products of translating mRNA by ribosomes. Ribosomes are composed of two subunits, a small subunit and a large subunit, 40S and 60S, respectively, in eukaryotic cells. In Saccharomyces cerevisiae, the 40S and 60S subunits are assembled from a large primary 35 S rRNA transcribed by RNA polymerase I. Processing of this rRNA yields 5.8S, 18S, and 25S rRNAs. The 5S rRNA is transcribed by RNA polymerase III separately (see reviews in Refs. 1-4). In yeast, 5S, 5.8S, and 25S (28S in higher eukaryotes) rRNA assemble with 39 ribosomal proteins to make up the 60S subunit, whereas 18S rRNA and 33 ribosomal proteins constitute the 40S subunit (5-7).Ribosome biogenesis is necessary for cell growth and proliferation. The synthesis of ribosome is a complex pathway in which over 200 trans-acting factors are involved. Many of the RNA folding, protein assembly, and maturation events are hierarchical, requiring the correct completion of one event to progress to the next event. This is seen in the assembly of ribosomal proteins onto the RNA in bacterial ribosome assembly (8) as well as in cytoplasmic maturation of the large subunit in yeast (9, 10). In addition, trans-acting factors also perform quality control steps for the assembly of the protein synthesis machinery. Syo1 facilitates the synchronized import of the two 5S rRNA-binding proteins, Rpl5 and Rpl11, to ensure stoichiometric the incorporation of these two proteins into the pre-60S subunits and also works as an assembly platform for the 5S ribonucleoprotein (RNP) (11,12). Release of the anti-association factor Tif6 requires elongation factor-like Efl1 and tRNAlike Sdo1 to confirm the integrity of the P-site (13-15). Transacting factors on cytoplasmic pre-40S subuni...

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Crystal structure of the 80S yeast ribosome

Cited by 129 publications

References 50 publications

A Puzzle of Life: Crafting Ribosomal Subunits

A Puzzle of Life: Crafting Ribosomal Subunits

Bcp1 Is the Nuclear Chaperone of Rpl23 in Saccharomyces cerevisiae

The Roles of Puf6 and Loc1 in 60S Biogenesis Are Interdependent, and Both Are Required for Efficient Accommodation of Rpl43

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