Overview
| Uniprot ID | P0CG47 |
|---|
| Protein Name | Polyubiquitin-B |
|---|
| Gene Name | UBB |
|---|
| Organism | Homo sapiens |
|---|
Kla Sites from experimental identification
| Position |
Flanking peptide |
| 158 |
GGMQIFVKTLTGKTI |
| 6 |
**MQIFVKTLTGKTI |
| 82 |
GGMQIFVKTLTGKTI |
Function
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
Protein Sequence
10
MQIFVKTLTG
20
KTITLEVEPS
30
DTIENVKAKI
40
QDKEGIPPDQ
50
QRLIFAGKQL
60
EDGRTLSDYN
70
IQKESTLHLV
80
LRLRGGMQIF
90
VKTLTGKTIT
100
LEVEPSDTIE
110
NVKAKIQDKE
120
GIPPDQQRLI
130
FAGKQLEDGR
140
TLSDYNIQKE
150
STLHLVLRLR
160
GGMQIFVKTL
170
TGKTITLEVE
180
PSDTIENVKA
190
KIQDKEGIPP
200
DQQRLIFAGK
210
QLEDGRTLSD
220
YNIQKESTLH
LVLRLRGGC
Gene Ontology
| Classification |
GO ID |
Description |
| Cellular Component |
GO:0005829 |
cytosol |
| Cellular Component |
GO:0022626 |
cytosolic ribosome |
| Cellular Component |
GO:0030666 |
endocytic vesicle membrane |
| Cellular Component |
GO:0005789 |
endoplasmic reticulum membrane |
| Cellular Component |
GO:0010008 |
endosome membrane |
| Cellular Component |
GO:0070062 |
extracellular exosome |
| Cellular Component |
GO:0005615 |
extracellular space |
| Cellular Component |
GO:0005741 |
mitochondrial outer membrane |
| Cellular Component |
GO:0005739 |
mitochondrion |
| Cellular Component |
GO:0043005 |
neuron projection |
| Cellular Component |
GO:0043025 |
neuronal cell body |
| Cellular Component |
GO:0005654 |
nucleoplasm |
| Cellular Component |
GO:0005634 |
nucleus |
| Cellular Component |
GO:0005886 |
plasma membrane |
| Cellular Component |
GO:0031982 |
vesicle |
| Molecular Function |
GO:0031386 |
protein tag activity |
| Molecular Function |
GO:0030170 |
pyridoxal phosphate binding |
| Molecular Function |
GO:0003735 |
structural constituent of ribosome |
| Biological Process |
GO:0047497 |
mitochondrion transport along microtubule |
| Biological Process |
GO:0019941 |
modification-dependent protein catabolic process |
| Biological Process |
GO:0048812 |
neuron projection morphogenesis |
| Biological Process |
GO:1902255 |
positive regulation of intrinsic apoptotic signaling pathway by p53 class mediator |
| Biological Process |
GO:1902527 |
positive regulation of protein monoubiquitination |
| Biological Process |
GO:0031398 |
positive regulation of protein ubiquitination |
| Biological Process |
GO:0051289 |
protein homotetramerization |
| Biological Process |
GO:0016567 |
protein ubiquitination |
| Biological Process |
GO:0051881 |
regulation of mitochondrial membrane potential |
| Biological Process |
GO:0043523 |
regulation of neuron apoptotic process |
| Biological Process |
GO:0061136 |
regulation of proteasomal protein catabolic process |
Reference
[1] Yan M, Tu H, Tang S, Gai Z, Shi Q et al.. Lactylated Proteomic Analysis Reveals Functional Implications of Lysine Lactylation In Asthenozoospermia.. Mol Cell Proteomics 24(12):101439. 2025 Dec. PMID: 41192556.