Ubiquitin-60S ribosomal protein L40 (CEP52) (Ubiquitin A-52 residue ribosomal protein fusion product 1) [Cleaved into: Ubiquitin; 60S ribosomal protein L40 (Large ribosomal subunit protein eL40)]
1_MQIFV 6_ KTLTG 11_ KTITL 16_ EVEPS 21_ DTIEN 26_ VKAKI 31_ QDKEG 36_ IPPDQ 41_ QRLIF 46_ AGKQL 51_ EDGRT 56_ LSDYN 61_ IQKES 66_ TLHLV 71_ LRLRG 76_ GIIEP 81_ SLRQL 86_ AQKYN 91_ CDKMI 96_ CRKCY 101_ ARLHP 106_ RAVNC 111_ RKKKC 116_ GHTNN 121_LRPKK
1: 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 proteotoxic stress response and cell cycle; 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, DNA-damage responses as well as in signaling processes leading to activation of the transcription factor NF-kappa-B. 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
2: Component of the 60S subunit of the ribosome (PubMed:23169626, PubMed:23636399, PubMed:32669547, PubMed:39048817, PubMed:39103523). Ribosomal protein L40 is essential for translation of a subset of cellular transcripts, and especially for cap-dependent translation of vesicular stomatitis virus mRNAs (PubMed:23169626, PubMed:23636399, PubMed:32669547, PubMed:39048817, PubMed:39103523)