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Ubiquitin-40S ribosomal protein S27a



Drosophila melanogaster (Fruit fly)
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli


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-48-linked is involved in protein degradation via the proteasome. 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).By similarity
Ribosomal protein S27a is a component of the 40S subunit of the ribosome.


In Drosophila ubiquitin is encoded by 3 different genes. RpL40 and RpS27A genes code for a single copy of ubiquitin fused to the ribosomal proteins L40 and S27a, respectively. Ubi-p63E gene codes for a polyubiquitin precursor with exact head to tail repeats.
For a better understanding, features related to ubiquitin are only indicated for the first chain.


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Binding sitei54Activating enzyme1
Sitei68Essential for function1
Binding sitei72Activating enzyme1


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Zinc fingeri121 – 144C4-typeAdd BLAST24

GO - Molecular functioni

  • metal ion binding Source: UniProtKB-KW
  • protein tag Source: FlyBase
  • structural constituent of ribosome Source: FlyBase

GO - Biological processi

  • cytoplasmic translation Source: FlyBase
  • Notch signaling pathway Source: Reactome
  • protein ubiquitination Source: FlyBase


Molecular functionRibonucleoprotein, Ribosomal protein
LigandMetal-binding, Zinc

Enzyme and pathway databases

ReactomeiR-DME-110312. Translesion synthesis by REV1.
R-DME-110320. Translesion Synthesis by POLH.
R-DME-1169091. Activation of NF-kappaB in B cells.
R-DME-1234176. Oxygen-dependent proline hydroxylation of Hypoxia-inducible Factor Alpha.
R-DME-1253288. Downregulation of ERBB4 signaling.
R-DME-1295596. Spry regulation of FGF signaling.
R-DME-1358803. Downregulation of ERBB2:ERBB3 signaling.
R-DME-156827. L13a-mediated translational silencing of Ceruloplasmin expression.
R-DME-174048. APC/C:Cdc20 mediated degradation of Cyclin B.
R-DME-174084. Autodegradation of Cdh1 by Cdh1:APC/C.
R-DME-174113. SCF-beta-TrCP mediated degradation of Emi1.
R-DME-174178. APC/C:Cdh1 mediated degradation of Cdc20 and other APC/C:Cdh1 targeted proteins in late mitosis/early G1.
R-DME-174184. Cdc20:Phospho-APC/C mediated degradation of Cyclin A.
R-DME-179409. APC-Cdc20 mediated degradation of Nek2A.
R-DME-1799339. SRP-dependent cotranslational protein targeting to membrane.
R-DME-182971. EGFR downregulation.
R-DME-187577. SCF(Skp2)-mediated degradation of p27/p21.
R-DME-195253. Degradation of beta-catenin by the destruction complex.
R-DME-201681. TCF dependent signaling in response to WNT.
R-DME-209560. NF-kB is activated and signals survival.
R-DME-2122948. Activated NOTCH1 Transmits Signal to the Nucleus.
R-DME-2173788. Downregulation of TGF-beta receptor signaling.
R-DME-2173791. TGF-beta receptor signaling in EMT (epithelial to mesenchymal transition).
R-DME-2173795. Downregulation of SMAD2/3:SMAD4 transcriptional activity.
R-DME-2173796. SMAD2/SMAD3:SMAD4 heterotrimer regulates transcription.
R-DME-2559582. Senescence-Associated Secretory Phenotype (SASP).
R-DME-2979096. NOTCH2 Activation and Transmission of Signal to the Nucleus.
R-DME-3769402. Deactivation of the beta-catenin transactivating complex.
R-DME-446652. Interleukin-1 signaling.
R-DME-450302. activated TAK1 mediates p38 MAPK activation.
R-DME-450321. JNK (c-Jun kinases) phosphorylation and activation mediated by activated human TAK1.
R-DME-4608870. Asymmetric localization of PCP proteins.
R-DME-4641257. Degradation of AXIN.
R-DME-4641258. Degradation of DVL.
R-DME-5205685. Pink/Parkin Mediated Mitophagy.
R-DME-532668. N-glycan trimming in the ER and Calnexin/Calreticulin cycle.
R-DME-5358346. Hedgehog ligand biogenesis.
R-DME-5607761. Dectin-1 mediated noncanonical NF-kB signaling.
R-DME-5610780. Degradation of GLI1 by the proteasome.
R-DME-5610785. GLI3 is processed to GLI3R by the proteasome.
R-DME-5632684. Hedgehog 'on' state.
R-DME-5654726. Negative regulation of FGFR1 signaling.
R-DME-5654727. Negative regulation of FGFR2 signaling.
R-DME-5654732. Negative regulation of FGFR3 signaling.
R-DME-5654733. Negative regulation of FGFR4 signaling.
R-DME-5655862. Translesion synthesis by POLK.
R-DME-5656121. Translesion synthesis by POLI.
R-DME-5656169. Termination of translesion DNA synthesis.
R-DME-5675221. Negative regulation of MAPK pathway.
R-DME-5675482. Regulation of necroptotic cell death.
R-DME-5676590. NIK-->noncanonical NF-kB signaling.
R-DME-5689603. UCH proteinases.
R-DME-5689877. Josephin domain DUBs.
R-DME-5689880. Ub-specific processing proteases.
R-DME-5689896. Ovarian tumor domain proteases.
R-DME-5689901. Metalloprotease DUBs.
R-DME-5693565. Recruitment and ATM-mediated phosphorylation of repair and signaling proteins at DNA double strand breaks.
R-DME-5696394. DNA Damage Recognition in GG-NER.
R-DME-5696395. Formation of Incision Complex in GG-NER.
R-DME-6781823. Formation of TC-NER Pre-Incision Complex.
R-DME-6782135. Dual incision in TC-NER.
R-DME-6782210. Gap-filling DNA repair synthesis and ligation in TC-NER.
R-DME-6791226. Major pathway of rRNA processing in the nucleolus and cytosol.
R-DME-6807004. Negative regulation of MET activity.
R-DME-68949. Orc1 removal from chromatin.
R-DME-69017. CDK-mediated phosphorylation and removal of Cdc6.
R-DME-69229. Ubiquitin-dependent degradation of Cyclin D1.
R-DME-69231. Cyclin D associated events in G1.
R-DME-69601. Ubiquitin Mediated Degradation of Phosphorylated Cdc25A.
R-DME-72649. Translation initiation complex formation.
R-DME-72689. Formation of a pool of free 40S subunits.
R-DME-72695. Formation of the ternary complex, and subsequently, the 43S complex.
R-DME-72702. Ribosomal scanning and start codon recognition.
R-DME-72706. GTP hydrolysis and joining of the 60S ribosomal subunit.
R-DME-8849469. PTK6 Regulates RTKs and Their Effectors AKT1 and DOK1.
R-DME-8854050. FBXL7 down-regulates AURKA during mitotic entry and in early mitosis.
R-DME-8863795. Downregulation of ERBB2 signaling.
R-DME-8866652. Synthesis of active ubiquitin: roles of E1 and E2 enzymes.
R-DME-8866654. E3 ubiquitin ligases ubiquitinate target proteins.
R-DME-8941858. Regulation of RUNX3 expression and activity.
R-DME-901032. ER Quality Control Compartment (ERQC).
R-DME-912631. Regulation of signaling by CBL.
R-DME-917729. Endosomal Sorting Complex Required For Transport (ESCRT).
R-DME-917937. Iron uptake and transport.
R-DME-937039. IRAK1 recruits IKK complex.
R-DME-937042. IRAK2 mediated activation of TAK1 complex.
R-DME-937072. TRAF6 mediated induction of TAK1 complex.
R-DME-975110. TRAF6 mediated IRF7 activation in TLR7/8 or 9 signaling.
R-DME-975144. IRAK1 recruits IKK complex upon TLR7/8 or 9 stimulation.
R-DME-975163. IRAK2 mediated activation of TAK1 complex upon TLR7/8 or 9 stimulation.
R-DME-975956. Nonsense Mediated Decay (NMD) independent of the Exon Junction Complex (EJC).
R-DME-975957. Nonsense Mediated Decay (NMD) enhanced by the Exon Junction Complex (EJC).
R-DME-983168. Antigen processing: Ubiquitination & Proteasome degradation.

Names & Taxonomyi

Protein namesi
Recommended name:
Ubiquitin-40S ribosomal protein S27a
Cleaved into the following 2 chains:
Gene namesi
Synonyms:UB3-D, UBI-F80, Ubi-m
ORF Names:CG5271
OrganismiDrosophila melanogaster (Fruit fly)
Taxonomic identifieri7227 [NCBI]
Taxonomic lineageiEukaryotaMetazoaEcdysozoaArthropodaHexapodaInsectaPterygotaNeopteraHolometabolaDipteraBrachyceraMuscomorphaEphydroideaDrosophilidaeDrosophilaSophophora
  • UP000000803 Componenti: Chromosome 2L

Organism-specific databases

FlyBaseiFBgn0003942. RpS27A.

Subcellular locationi

Ubiquitin :

GO - Cellular componenti

  • cytosol Source: Reactome
  • cytosolic small ribosomal subunit Source: FlyBase
  • nucleus Source: UniProtKB-SubCell

Keywords - Cellular componenti

Cytoplasm, Nucleus

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00003964821 – 76UbiquitinAdd BLAST76
ChainiPRO_000039648377 – 15640S ribosomal protein S27aAdd BLAST80

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Cross-linki48Glycyl lysine isopeptide (Lys-Gly) (interchain with G-Cter in ubiquitin)
Cross-linki76Glycyl lysine isopeptide (Gly-Lys) (interchain with K-? in acceptor proteins)

Keywords - PTMi

Isopeptide bond, Ubl conjugation

Proteomic databases



Gene expression databases

ExpressionAtlasiP15357. differential.
GenevisibleiP15357. DM.


Subunit structurei

Ribosomal protein S27a is part of the 40S ribosomal subunit.By similarity

Protein-protein interaction databases

BioGridi60502. 89 interactors.
IntActiP15357. 7 interactors.


3D structure databases

Select the link destinations:
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
4V6Welectron microscopy6.00Af77-156[»]

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini1 – 76Ubiquitin-likePROSITE-ProRule annotationAdd BLAST76

Compositional bias

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Compositional biasi78 – 107Lys-richAdd BLAST30

Sequence similaritiesi

In the N-terminal section; belongs to the ubiquitin family.Curated
In the C-terminal section; belongs to the eukaryotic ribosomal protein eS31 family.Curated

Zinc finger

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Zinc fingeri121 – 144C4-typeAdd BLAST24

Keywords - Domaini


Phylogenomic databases

eggNOGiKOG0004. Eukaryota.
COG5272. LUCA.

Family and domain databases

InterProiView protein in InterPro
IPR002906. Ribosomal_S27a.
IPR011332. Ribosomal_zn-bd.
IPR019956. Ubiquitin.
IPR029071. Ubiquitin-rel_dom.
IPR019954. Ubiquitin_CS.
IPR000626. Ubiquitin_dom.
PfamiView protein in Pfam
PF01599. Ribosomal_S27. 1 hit.
PF00240. ubiquitin. 1 hit.
SMARTiView protein in SMART
SM01402. Ribosomal_S27. 1 hit.
SM00213. UBQ. 1 hit.
SUPFAMiSSF54236. SSF54236. 1 hit.
SSF57829. SSF57829. 1 hit.
PROSITEiView protein in PROSITE
PS00299. UBIQUITIN_1. 1 hit.
PS50053. UBIQUITIN_2. 1 hit.


Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P15357-1 [UniParc]FASTAAdd to basket

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Mass (Da):17,940
Last modified:August 10, 2010 - v2

Sequence cautioni

The sequence CAA48871 differs from that shown. Reason: Erroneous gene model prediction.Curated

Sequence databases

Select the link destinations:
Links Updated
M22536 mRNA. Translation: AAA28998.1.
X69119 Genomic DNA. Translation: CAA48871.1. Sequence problems.
AE014134 Genomic DNA. Translation: AAF52941.1.
RefSeqiNP_476778.1. NM_057430.4.

Genome annotation databases

EnsemblMetazoaiFBtr0080016; FBpp0079606; FBgn0003942.

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.

Entry informationi

Entry nameiRS27A_DROME
AccessioniPrimary (citable) accession number: P15357
Secondary accession number(s): P68198
, Q0E8I1, Q9VKW6, Q9VQX7, Q9VZL4
Entry historyiIntegrated into UniProtKB/Swiss-Prot: April 1, 1990
Last sequence update: August 10, 2010
Last modified: July 5, 2017
This is version 141 of the entry and version 2 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programDrosophila annotation project


Keywords - Technical termi

3D-structure, Complete proteome, Reference proteome


  1. Drosophila
    Drosophila: entries, gene names and cross-references to FlyBase
  2. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  3. Ribosomal proteins
    Ribosomal proteins families and list of entries
  4. SIMILARITY comments
    Index of protein domains and families