ubiquitin recycling
Definition
Target type: biologicalprocess
Any process involved in the maintenance of an internal steady state of ubiquitin monomers and free ubiquitin chains at the level of the cell by recycling ubiquitin from proteasome-bound ubiquitinated intermediates. [GOC:BHF, GOC:dph, GOC:tb, PMID:19410548]
Ubiquitin recycling is a crucial cellular process that ensures the efficient reuse of ubiquitin, a small protein involved in protein degradation and other cellular processes. Ubiquitin is a highly conserved protein that is attached to target proteins as a polyubiquitin chain, marking them for degradation by the proteasome. After the proteasome degrades the target protein, the ubiquitin chains are removed and recycled for further use.
The process of ubiquitin recycling involves several key steps:
1. **Deubiquitination:** Ubiquitin chains are removed from the target protein by deubiquitinases (DUBs). DUBs are a family of enzymes that specifically cleave the isopeptide bonds between ubiquitin molecules. There are many different DUBs, each with its own substrate specificity.
2. **Ubiquitin refolding:** Once removed from the target protein, ubiquitin molecules may become misfolded due to their interaction with the proteasome or other cellular components. To be recycled, ubiquitin must refold into its native conformation. This process is assisted by molecular chaperones such as Hsp70 and Hsp90.
3. **Ubiquitin conjugation:** The refolded ubiquitin molecules can then be re-conjugated to new target proteins. This process is catalyzed by ubiquitin ligases (E3s), which are enzymes that attach ubiquitin to target proteins. The ubiquitin ligase-mediated conjugation requires the coordinated action of E1 and E2 enzymes, which activate and transfer ubiquitin, respectively.
Ubiquitin recycling is a dynamic process that is tightly regulated by a complex network of enzymes and proteins. This process ensures that ubiquitin is available for protein degradation and other cellular processes. Defects in ubiquitin recycling can lead to the accumulation of misfolded proteins, which can contribute to various diseases, including neurodegenerative disorders and cancer.
Ubiquitin recycling is also a highly regulated process, with several mechanisms in place to prevent the accumulation of free ubiquitin in the cell. For example, ubiquitin can be sequestered in specific cellular compartments or degraded by specific proteases. These mechanisms ensure that ubiquitin levels are tightly controlled and that the recycling process operates efficiently.'
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Proteins (2)
| Protein | Definition | Taxonomy |
|---|---|---|
| Phospholipase A-2-activating protein | A phospholipase A-2-activating protein that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9Y263] | Homo sapiens (human) |
| Insulin-degrading enzyme | An insulin-degrading enzyme that is encoded in the genome of human. [PRO:DNx, UniProtKB:P14735] | Homo sapiens (human) |
Compounds (15)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| theophylline | dimethylxanthine | adenosine receptor antagonist; anti-asthmatic drug; anti-inflammatory agent; bronchodilator agent; drug metabolite; EC 3.1.4.* (phosphoric diester hydrolase) inhibitor; fungal metabolite; human blood serum metabolite; immunomodulator; muscle relaxant; vasodilator agent | |
| ebselen | ebselen : A benzoselenazole that is 1,2-benzoselenazol-3-one carrying an additional phenyl substituent at position 2. Acts as a mimic of glutathione peroxidase. | benzoselenazole | anti-inflammatory drug; antibacterial agent; anticoronaviral agent; antifungal agent; antineoplastic agent; antioxidant; apoptosis inducer; EC 1.13.11.33 (arachidonate 15-lipoxygenase) inhibitor; EC 1.13.11.34 (arachidonate 5-lipoxygenase) inhibitor; EC 1.3.1.8 [acyl-CoA dehydrogenase (NADP(+))] inhibitor; EC 1.8.1.12 (trypanothione-disulfide reductase) inhibitor; EC 2.5.1.7 (UDP-N-acetylglucosamine 1-carboxyvinyltransferase) inhibitor; EC 2.7.10.1 (receptor protein-tyrosine kinase) inhibitor; EC 3.1.3.25 (inositol-phosphate phosphatase) inhibitor; EC 3.4.22.69 (SARS coronavirus main proteinase) inhibitor; EC 3.5.4.1 (cytosine deaminase) inhibitor; EC 5.1.3.2 (UDP-glucose 4-epimerase) inhibitor; enzyme mimic; ferroptosis inhibitor; genotoxin; hepatoprotective agent; neuroprotective agent; radical scavenger |
| rabeprazole | Rabeprazole: A 4-(3-methoxypropoxy)-3-methylpyridinyl derivative of timoprazole that is used in the therapy of STOMACH ULCERS and ZOLLINGER-ELLISON SYNDROME. The drug inhibits H(+)-K(+)-EXCHANGING ATPASE which is found in GASTRIC PARIETAL CELLS. | benzimidazoles; pyridines; sulfoxide | anti-ulcer drug; EC 3.6.3.10 (H(+)/K(+)-exchanging ATPase) inhibitor |
| leucine | leucine : A branched-chain amino acid that consists of glycine in which one of the hydrogens attached to the alpha-carbon is substituted by an isobutyl group. Leucine: An essential branched-chain amino acid important for hemoglobin formation. | amino acid zwitterion; L-alpha-amino acid; leucine; proteinogenic amino acid; pyruvate family amino acid | algal metabolite; Escherichia coli metabolite; human metabolite; mouse metabolite; plant metabolite; Saccharomyces cerevisiae metabolite |
| phenylalanine | L-phenylalanine : The L-enantiomer of phenylalanine. phenylalanine : An aromatic amino acid that is alanine in which one of the methyl hydrogens is substituted by a phenyl group. Phenylalanine: An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE. | amino acid zwitterion; erythrose 4-phosphate/phosphoenolpyruvate family amino acid; L-alpha-amino acid; phenylalanine; proteinogenic amino acid | algal metabolite; EC 3.1.3.1 (alkaline phosphatase) inhibitor; Escherichia coli metabolite; human xenobiotic metabolite; micronutrient; mouse metabolite; nutraceutical; plant metabolite; Saccharomyces cerevisiae metabolite |
| tryptophan | tryptophan : An alpha-amino acid that is alanine bearing an indol-3-yl substituent at position 3. Tryptophan: An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals. | erythrose 4-phosphate/phosphoenolpyruvate family amino acid; L-alpha-amino acid; L-alpha-amino acid zwitterion; proteinogenic amino acid; tryptophan; tryptophan zwitterion | antidepressant; Escherichia coli metabolite; human metabolite; micronutrient; mouse metabolite; nutraceutical; plant metabolite; Saccharomyces cerevisiae metabolite |
| homoarginine | L-homoarginine : An L-lysine derivative that is the L-enantiomer of homoarginine. | homoarginine; L-lysine derivative; non-proteinogenic L-alpha-amino acid | biomarker; EC 3.1.3.1 (alkaline phosphatase) inhibitor; human metabolite; rat metabolite; xenobiotic metabolite |
| levamisole | levamisole : A 6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b][1,3]thiazole that has S configuration. It is used (generally as the monohydrochloride salt) to treat parasitic worm infections in pigs, sheep and cattle and was formerly used in humans as an adjuvant to chemotherapy for the treatment of various cancers. It is also widely used as an adulterant to coccaine. Levamisole: An antihelminthic drug that has been tried experimentally in rheumatic disorders where it apparently restores the immune response by increasing macrophage chemotaxis and T-lymphocyte function. Paradoxically, this immune enhancement appears to be beneficial in rheumatoid arthritis where dermatitis, leukopenia, and thrombocytopenia, and nausea and vomiting have been reported as side effects. (From Smith and Reynard, Textbook of Pharmacology, 1991, p435-6) | 6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b][1,3]thiazole | antinematodal drug; antirheumatic drug; EC 3.1.3.1 (alkaline phosphatase) inhibitor; immunological adjuvant; immunomodulator |
| cefmetazole | cefmetazole : A second-generation cephalosporin antibiotic having N(1)-methyltetrazol-5-ylthiomethyl, {[(cyanomethyl)sulfanyl]acetyl}amino and methoxy side-groups at positions 3, 7beta and 7alpha respectively of the parent cephem bicyclic structure. Cefmetazole: A semisynthetic cephamycin antibiotic with a broad spectrum of activity against both gram-positive and gram-negative microorganisms. It has a high rate of efficacy in many types of infection and to date no severe side effects have been noted. | cephalosporin | antibacterial drug |
| 1-(3,4-dihydroxyphenyl)-2-(1-imidazolyl)ethanone | aromatic ketone | ||
| 1-(3,4-dihydroxyphenyl)-2-[(4,6-dimethyl-2-pyrimidinyl)thio]ethanone | aromatic ketone | ||
| 2,5-dimethoxy-n-(quinolin-3-yl)benzenesulfonamide | 2,5-dimethoxy-N-(quinolin-3-yl)benzenesulfonamide: a tissue-nonspecific alkaline phosphatase inhibitor; structure in first source | quinolines | |
| myricetin | 7-hydroxyflavonol; hexahydroxyflavone | antineoplastic agent; antioxidant; cyclooxygenase 1 inhibitor; food component; geroprotector; hypoglycemic agent; plant metabolite | |
| fr 148083 | 5Z-7-oxozeaenol : A macrolide that is the 7-oxo derivative of zeaenol (the 5Z stereoisomer). Isolated from Fungi, it exhibits cytotoxic, antibacterial and inhibitory activity against NF-kappaB. | aromatic ether; macrolide; phenols; secondary alcohol; secondary alpha-hydroxy ketone | antibacterial agent; antineoplastic agent; metabolite; NF-kappaB inhibitor |
| rolitetracycline | rolitetracycline : A derivative of tetracycline in which the amide function is substituted with a pyrrolidinomethyl group. Rolitetracycline: A pyrrolidinylmethyl TETRACYCLINE. |