| Structural highlights
Function
[RS21A_YEAST] Required for the processing of the 20S rRNA-precursor to mature 18S rRNA in a late step of the maturation of 40S ribosomal subunits. Has a physiological role leading to 18S rRNA stability.[1] [RL12A_YEAST] This protein binds directly to 26S ribosomal RNA.[HAMAP-Rule:MF_00736] [RL401_YEAST] Ubiquitin: exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, and DNA-damage responses. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling (By similarity).[2] 60S ribosomal protein L40: component of the 60S subunit of the ribosome. Ribosomal protein L40 is essential for translation of a subset of cellular transcripts, including stress response transcripts, such as DDR2.[3] [RS7A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly.[4] [RLA0_YEAST] Ribosomal protein P0 is the functional equivalent of E.coli protein L10. [RS15_YEAST] Involved in the nuclear export of the small ribosomal subunit. Has a role in the late stage of the assembly of pre-40S particles within the nucleus and controls their export to the cytoplasm.[5] [RL25_YEAST] This protein binds to a specific region on the 26S rRNA. [RS14A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly.[6] [RL37A_YEAST] Binds to the 23S rRNA (By similarity). [RL11A_YEAST] Binds to 5S ribosomal RNA. [RS27A_YEAST] Ubiquitin exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, and DNA-damage responses. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling (By similarity). 40S ribosomal protein S31 is a component of the 40S subunit of the ribosome (By similarity). [RS2_YEAST] Important in the assembly and function of the 40S ribosomal subunit. Mutations in this protein affects the control of translational fidelity. Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly.[7] [RS6A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly.[8] [RS18A_YEAST] Located at the top of the head of the 40S subunit, it contacts several helices of the 18S rRNA (By similarity).[HAMAP-Rule:MF_01315] [RS19A_YEAST] Required for proper maturation of the small (40S) ribosomal subunit. Binds to 40s pre-ribosomal particles, probably required after association of NOC4 but before association of ENP1, TSR1 and RIO2 with 20/21S pre-rRNA.[9] [10] [RS9A_YEAST] Involved in nucleolar processing of pre-18S ribosomal RNA and ribosome assembly.[11] [GBLP_YEAST] Located at the head of the 40S ribosomal subunit in the vicinity of the mRNA exit channel, it serves as a scaffold protein that can recruit other proteins to the ribosome. Involved in the negative regulation of translation of a specific subset of proteins.[12] [RL5_YEAST] Binds 5S RNA and is required for 60S subunit assembly. [RL4A_YEAST] Participates in the regulation of the accumulation of its own mRNA.[13]
Publication Abstract from PubMed
Internal ribosome entry sites (IRESs) mediate cap-independent translation of viral mRNAs. Using electron cryo-microscopy of a single specimen, we present five ribosome structures formed with the Taura syndrome virus IRES and translocase eEF2*GTP bound with sordarin. The structures suggest a trajectory of IRES translocation, required for translation initiation, and provide an unprecedented view of eEF2 dynamics. The IRES rearranges from extended to bent to extended conformations. This inchworm-like movement is coupled with ribosomal inter-subunit rotation and 40S head swivel. eEF2, attached to the 60S subunit, slides along the rotating 40S subunit to enter the A site. Its diphthamide-bearing tip at domain IV separates the tRNA-mRNA-like pseudoknot I (PKI) of the IRES from the decoding center. This unlocks 40S domains, facilitating head swivel and biasing IRES translocation via hitherto-elusive intermediates with PKI captured between the A and P sites. The structures suggest missing links in our understanding of tRNA translocation.
Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome.,Abeyrathne PD, Koh CS, Grant T, Grigorieff N, Korostelev AA Elife. 2016 May 9;5. pii: e14874. doi: 10.7554/eLife.14874. PMID:27159452[14]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Tabb-Massey A, Caffrey JM, Logsden P, Taylor S, Trent JO, Ellis SR. Ribosomal proteins Rps0 and Rps21 of Saccharomyces cerevisiae have overlapping functions in the maturation of the 3' end of 18S rRNA. Nucleic Acids Res. 2003 Dec 1;31(23):6798-805. PMID:14627813
- ↑ Lee AS, Burdeinick-Kerr R, Whelan SP. A ribosome-specialized translation initiation pathway is required for cap-dependent translation of vesicular stomatitis virus mRNAs. Proc Natl Acad Sci U S A. 2013 Jan 2;110(1):324-9. doi: 10.1073/pnas.1216454109. , Epub 2012 Nov 19. PMID:23169626 doi:http://dx.doi.org/10.1073/pnas.1216454109
- ↑ Lee AS, Burdeinick-Kerr R, Whelan SP. A ribosome-specialized translation initiation pathway is required for cap-dependent translation of vesicular stomatitis virus mRNAs. Proc Natl Acad Sci U S A. 2013 Jan 2;110(1):324-9. doi: 10.1073/pnas.1216454109. , Epub 2012 Nov 19. PMID:23169626 doi:http://dx.doi.org/10.1073/pnas.1216454109
- ↑ Bernstein KA, Gallagher JE, Mitchell BM, Granneman S, Baserga SJ. The small-subunit processome is a ribosome assembly intermediate. Eukaryot Cell. 2004 Dec;3(6):1619-26. PMID:15590835 doi:http://dx.doi.org/10.1128/EC.3.6.1619-1626.2004
- ↑ Leger-Silvestre I, Milkereit P, Ferreira-Cerca S, Saveanu C, Rousselle JC, Choesmel V, Guinefoleau C, Gas N, Gleizes PE. The ribosomal protein Rps15p is required for nuclear exit of the 40S subunit precursors in yeast. EMBO J. 2004 Jun 16;23(12):2336-47. Epub 2004 May 27. PMID:15167894 doi:http://dx.doi.org/10.1038/sj.emboj.7600252
- ↑ Bernstein KA, Gallagher JE, Mitchell BM, Granneman S, Baserga SJ. The small-subunit processome is a ribosome assembly intermediate. Eukaryot Cell. 2004 Dec;3(6):1619-26. PMID:15590835 doi:http://dx.doi.org/10.1128/EC.3.6.1619-1626.2004
- ↑ Bernstein KA, Gallagher JE, Mitchell BM, Granneman S, Baserga SJ. The small-subunit processome is a ribosome assembly intermediate. Eukaryot Cell. 2004 Dec;3(6):1619-26. PMID:15590835 doi:http://dx.doi.org/10.1128/EC.3.6.1619-1626.2004
- ↑ Bernstein KA, Gallagher JE, Mitchell BM, Granneman S, Baserga SJ. The small-subunit processome is a ribosome assembly intermediate. Eukaryot Cell. 2004 Dec;3(6):1619-26. PMID:15590835 doi:http://dx.doi.org/10.1128/EC.3.6.1619-1626.2004
- ↑ Leger-Silvestre I, Caffrey JM, Dawaliby R, Alvarez-Arias DA, Gas N, Bertolone SJ, Gleizes PE, Ellis SR. Specific Role for Yeast Homologs of the Diamond Blackfan Anemia-associated Rps19 Protein in Ribosome Synthesis. J Biol Chem. 2005 Nov 18;280(46):38177-85. Epub 2005 Sep 12. PMID:16159874 doi:http://dx.doi.org/10.1074/jbc.M506916200
- ↑ Gregory LA, Aguissa-Toure AH, Pinaud N, Legrand P, Gleizes PE, Fribourg S. Molecular basis of Diamond-Blackfan anemia: structure and function analysis of RPS19. Nucleic Acids Res. 2007;35(17):5913-21. Epub 2007 Aug 28. PMID:17726054 doi:10.1093/nar/gkm626
- ↑ Bernstein KA, Gallagher JE, Mitchell BM, Granneman S, Baserga SJ. The small-subunit processome is a ribosome assembly intermediate. Eukaryot Cell. 2004 Dec;3(6):1619-26. PMID:15590835 doi:http://dx.doi.org/10.1128/EC.3.6.1619-1626.2004
- ↑ Gerbasi VR, Weaver CM, Hill S, Friedman DB, Link AJ. Yeast Asc1p and mammalian RACK1 are functionally orthologous core 40S ribosomal proteins that repress gene expression. Mol Cell Biol. 2004 Sep;24(18):8276-87. PMID:15340087 doi:10.1128/MCB.24.18.8276-8287.2004
- ↑ Presutti C, Ciafre SA, Bozzoni I. The ribosomal protein L2 in S. cerevisiae controls the level of accumulation of its own mRNA. EMBO J. 1991 Aug;10(8):2215-21. PMID:2065661
- ↑ Abeyrathne PD, Koh CS, Grant T, Grigorieff N, Korostelev AA. Ensemble cryo-EM uncovers inchworm-like translocation of a viral IRES through the ribosome. Elife. 2016 May 9;5. pii: e14874. doi: 10.7554/eLife.14874. PMID:27159452 doi:http://dx.doi.org/10.7554/eLife.14874
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