6hd7

Structural highlights

Function

[RL11A_YEAST] Binds to 5S ribosomal RNA. [RL40A_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). 60S ribosomal protein L40-A: Component of the ribosome, a large ribonucleoprotein complex responsible for the synthesis of proteins in the cell. The small ribosomal subunit (SSU) binds messenger RNAs (mRNAs) and translates the encoded message by selecting cognate aminoacyl-transfer RNA (tRNA) molecules. The large subunit (LSU) contains the ribosomal catalytic site termed the peptidyl transferase center (PTC), which catalyzes the formation of peptide bonds, thereby polymerizing the amino acids delivered by tRNAs into a polypeptide chain. The nascent polypeptides leave the ribosome through a tunnel in the LSU and interact with protein factors that function in enzymatic processing, targeting, and the membrane insertion of nascent chains at the exit of the ribosomal tunnel (PubMed:22096102). eL40 is essential for translation of a subset of cellular transcripts, including stress response transcripts, such as DDR2 (PubMed:23169626).^{[1] [2]} [ARD1_YEAST] Catalytic component of the NatA N-terminal acetyltransferase, which catalyzes acetylation of proteins beginning with Met-Ser, Met-Gly and Met-Ala. N-acetylation plays a role in normal eukaryotic translation and processing, protect against proteolytic degradation and protein turnover.^[3] [RL4A_YEAST] Participates in the regulation of the accumulation of its own mRNA.^[4] [RL5_YEAST] Binds 5S RNA and is required for 60S subunit assembly. [NAT1_YEAST] Non-catalytic component of the NatA N-terminal acetyltransferase, which catalyzes acetylation of proteins beginning with Met-Ser, Met-Gly and Met-Ala. N-acetylation plays a role in normal eukaryotic translation and processing, protect against proteolytic degradation and protein turnover. NAT1 anchors ARD1 and NAT5 to the ribosome and may present the N termini of nascent polypeptides for acetylation.^{[5] [6]} [RL25_YEAST] This protein binds to a specific region on the 26S rRNA. [NAT5_YEAST] Non-essential component of the NatA N-terminal acetyltransferase, which catalyzes acetylation of proteins beginning with Met-Ser, Met-Gly and Met-Ala. N-acetylation plays a role in normal eukaryotic translation and processing, protect against proteolytic degradation and protein turnover. [RL37A_YEAST] Binds to the 23S rRNA (By similarity).

See Also

• Ribosome 3D structures

References

1. ↑ 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
2. ↑ Ben-Shem A, Garreau de Loubresse N, Melnikov S, Jenner L, Yusupova G, Yusupov M. The structure of the eukaryotic ribosome at 3.0 A resolution. Science. 2011 Dec 16;334(6062):1524-9. Epub 2011 Nov 17. PMID:22096102 doi:10.1126/science.1212642
3. ↑ Park EC, Szostak JW. ARD1 and NAT1 proteins form a complex that has N-terminal acetyltransferase activity. EMBO J. 1992 Jun;11(6):2087-93. PMID:1600941
4. ↑ 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
5. ↑ Park EC, Szostak JW. ARD1 and NAT1 proteins form a complex that has N-terminal acetyltransferase activity. EMBO J. 1992 Jun;11(6):2087-93. PMID:1600941
6. ↑ Gautschi M, Just S, Mun A, Ross S, Rucknagel P, Dubaquie Y, Ehrenhofer-Murray A, Rospert S. The yeast N(alpha)-acetyltransferase NatA is quantitatively anchored to the ribosome and interacts with nascent polypeptides. Mol Cell Biol. 2003 Oct;23(20):7403-14. PMID:14517307
7. ↑ Knorr AG, Schmidt C, Tesina P, Berninghausen O, Becker T, Beatrix B, Beckmann R. Ribosome-NatA architecture reveals that rRNA expansion segments coordinate N-terminal acetylation. Nat Struct Mol Biol. 2018 Dec 17. pii: 10.1038/s41594-018-0165-y. doi:, 10.1038/s41594-018-0165-y. PMID:30559462 doi:http://dx.doi.org/10.1038/s41594-018-0165-y