Overview
| Uniprot ID | P0CG48 |
|---|
| Protein Name | Polyubiquitin-C |
|---|
| Gene Name | UBC |
|---|
| Organism | Homo sapiens |
|---|
Kla Sites from experimental identification
| Position |
Flanking peptide |
| 158 |
GGMQIFVKTLTGKTI |
| 234 |
GGMQIFVKTLTGKTI |
| 310 |
GGMQIFVKTLTGKTI |
| 386 |
GGMQIFVKTLTGKTI |
| 462 |
GGMQIFVKTLTGKTI |
| 538 |
GGMQIFVKTLTGKTI |
| 6 |
**MQIFVKTLTGKTI |
| 614 |
GGMQIFVKTLTGKTI |
| 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. During ubiquitination, the acceptor ubiquitin is positioned in the active site via direct interaction with the E2 ubiquitin-conjugating enzymes such as UBE2R2 (PubMed:38326650). As a monoubiquitin, its C-terminal glycine is recognized as a C-degron by Cul2-RING (CRL2) E3 ubiquitin-protein ligase complexes (PubMed:39548056)
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
230
LVLRLRGGMQ
240
IFVKTLTGKT
250
ITLEVEPSDT
260
IENVKAKIQD
270
KEGIPPDQQR
280
LIFAGKQLED
290
GRTLSDYNIQ
300
KESTLHLVLR
310
LRGGMQIFVK
320
TLTGKTITLE
330
VEPSDTIENV
340
KAKIQDKEGI
350
PPDQQRLIFA
360
GKQLEDGRTL
370
SDYNIQKEST
380
LHLVLRLRGG
390
MQIFVKTLTG
400
KTITLEVEPS
410
DTIENVKAKI
420
QDKEGIPPDQ
430
QRLIFAGKQL
440
EDGRTLSDYN
450
IQKESTLHLV
460
LRLRGGMQIF
470
VKTLTGKTIT
480
LEVEPSDTIE
490
NVKAKIQDKE
500
GIPPDQQRLI
510
FAGKQLEDGR
520
TLSDYNIQKE
530
STLHLVLRLR
540
GGMQIFVKTL
550
TGKTITLEVE
560
PSDTIENVKA
570
KIQDKEGIPP
580
DQQRLIFAGK
590
QLEDGRTLSD
600
YNIQKESTLH
610
LVLRLRGGMQ
620
IFVKTLTGKT
630
ITLEVEPSDT
640
IENVKAKIQD
650
KEGIPPDQQR
660
LIFAGKQLED
670
GRTLSDYNIQ
680
KESTLHLVLR
LRGGV
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: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:0003723 |
RNA binding |
| Molecular Function |
GO:0003735 |
structural constituent of ribosome |
| Biological Process |
GO:0019941 |
modification-dependent protein catabolic process |
| Biological Process |
GO:0016567 |
protein ubiquitination |
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.