Target type: biologicalprocess
Any process that activates or increases the frequency, rate or extent of autophagy of the mitochondrion in response to mitochondrial depolarization. [GO_REF:0000058, GOC:pad, GOC:PARL, GOC:TermGenie, PMID:22020285]
Mitochondrial depolarization, a loss of the electrochemical gradient across the mitochondrial membrane, triggers a complex cellular response aimed at restoring homeostasis and preventing cell death. This response often involves the activation of autophagy, a process that degrades and recycles cellular components, including damaged mitochondria. This specific type of autophagy, targeting mitochondria, is known as mitophagy.
Here's a detailed breakdown of the biological process of positive regulation of autophagy of mitochondria in response to mitochondrial depolarization:
1. **Sensing Mitochondrial Depolarization:** The cell employs various mechanisms to detect the loss of membrane potential in mitochondria. Key sensors include:
* **PTEN-induced putative kinase 1 (PINK1):** In healthy mitochondria, PINK1 is rapidly degraded. However, upon depolarization, PINK1 accumulates on the mitochondrial outer membrane.
* **Parkin:** This E3 ubiquitin ligase is normally found in the cytosol. PINK1 recruits Parkin to the depolarized mitochondria, where it begins ubiquitinating mitochondrial proteins.
* **Other Sensors:** Additionally, the cell may utilize other sensors like reactive oxygen species (ROS) and Ca2+ levels to detect mitochondrial dysfunction.
2. **Ubiquitination Cascade:** Parkin, activated by PINK1, attaches ubiquitin chains to various proteins on the mitochondrial outer membrane. This ubiquitination signal serves as a "flag" marking the damaged mitochondria for destruction.
3. **Recruitment of Autophagy Machinery:** The ubiquitinated mitochondria become targets for autophagy receptors, such as p62/SQSTM1 and NDP52. These receptors bind to both the ubiquitin chains on the mitochondria and to the autophagic machinery.
4. **Formation of Autophagosomes:** The autophagy machinery, including LC3 and Atg proteins, assembles around the targeted mitochondria, engulfing them within a double-membrane vesicle known as an autophagosome.
5. **Fusion with Lysosomes:** The autophagosome then fuses with lysosomes, acidic organelles containing hydrolytic enzymes. These enzymes degrade the engulfed mitochondria, breaking them down into their constituent parts.
6. **Recycling and Homeostasis:** The breakdown products of the mitochondria are released into the cytosol, providing essential building blocks for the cell. This process helps restore cellular homeostasis and prevents the accumulation of damaged mitochondria.
7. **Regulation and Feedback Mechanisms:** The process of mitophagy is tightly regulated by a complex interplay of signaling pathways and feedback mechanisms. For example, mTOR signaling can inhibit autophagy, while AMPK activation can promote it.
This intricate process ensures that the cell can selectively remove damaged mitochondria, preventing their accumulation and the release of harmful substances, ultimately contributing to cell survival.
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Protein | Definition | Taxonomy |
---|---|---|
Hexokinase-2 | A hexokinase-2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P52789] | Homo sapiens (human) |
Lysosomal acid glucosylceramidase | A lysosomal acid glucosylceramidase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P04062] | Homo sapiens (human) |
Compound | Definition | Classes | Roles |
---|---|---|---|
ambroxol | Ambroxol: A metabolite of BROMHEXINE that stimulates mucociliary action and clears the air passages in the respiratory tract. It is usually administered as the hydrochloride. | aromatic amine | |
benserazide | benserazide : A carbohydrazide that results from the formal condensation of the carboxy group of DL-serine with the primary amino group of 4-(hydrazinylmethyl)benzene-1,2,3-triol. An aromatic-L-amino-acid decarboxylase inhibitor (DOPA decarboxylase inhibitor) that does not enter the central nervous system, it is used as its hydrochloride salt as an adjunct to levodopa in the treatment of parkinsonism. By preventing the conversion of levodopa to dopamine in the periphery, it causes an increase in the amount of levodopa reaching the central nervous system and so reduces the required dose. Benserazide has no antiparkinson actions when given alone. Benserazide: An inhibitor of DOPA DECARBOXYLASE that does not enter the central nervous system. It is often given with LEVODOPA in the treatment of parkinsonism to prevent the conversion of levodopa to dopamine in the periphery, thereby increasing the amount that reaches the central nervous system and reducing the required dose. It has no antiparkinson actions when given alone. | carbohydrazide; catechols; primary alcohol; primary amino compound | antiparkinson drug; dopaminergic agent; EC 4.1.1.28 (aromatic-L-amino-acid decarboxylase) inhibitor |
beta-glucono-1,5-lactone | beta-glucono-1,5-lactone: structure D-glucono-1,5-lactone : An aldono-1,5-lactone obtained from D-gluconic acid. | aldono-1,5-lactone; gluconolactone | animal metabolite; mouse metabolite |
1-deoxynojirimycin | 1-deoxy-nojirimycin: structure in first source duvoglustat : An optically active form of 2-(hydroxymethyl)piperidine-3,4,5-triol having 2R,3R,4R,5S-configuration. | 2-(hydroxymethyl)piperidine-3,4,5-triol; piperidine alkaloid | anti-HIV agent; anti-obesity agent; bacterial metabolite; EC 3.2.1.20 (alpha-glucosidase) inhibitor; hepatoprotective agent; hypoglycemic agent; plant metabolite |
miglustat | miglustat : A hydroxypiperidine that is deoxynojirimycin in which the amino hydrogen is replaced by a butyl group. miglustat: a glucosylceramide synthase inhibitor | piperidines; tertiary amino compound | anti-HIV agent; EC 2.4.1.80 (ceramide glucosyltransferase) inhibitor |
n-phenylphthalimide | N-phenylphthalimide: structure given in first source | ||
N-Benzylphthalimide | isoindoles | ||
1-(10h-phenothiazin-2-yl)ethanone | 1-(10H-phenothiazin-2-yl)ethanone: structure in first source | phenothiazines | |
mor-14 | N-methyldeoxynojirimycin: glucosidase inhibitor | hydroxypiperidine; piperidine alkaloid; tertiary amino compound | anti-HIV agent; cardioprotective agent; EC 3.2.1.20 (alpha-glucosidase) inhibitor; plant metabolite |
1,2,3,4-tetrahydroxy-nor-tropane | calystegine B(2): RN given for (2-endo,3-exo,4-endo)-isomer; structure in first source | ||
homonojirimycin | homonojirimycin: inhibits alpha-glucosidase; RN given for (2R-(2alpha,3alpha,4beta,5alpha,6beta))-isomer; structure in first source | ||
cyclophellitol | cyclophellitol: structure given in first source; isolated from Phellinus sp. | ||
calystegine a3 | calystegine A3: also inhibits beta-xylosidase; structure in first source | ||
miglitol | piperidines | ||
isofagomine | piperidines | ||
n-nonyl-1-deoxynojirimycin | N-nonyldeoxynojirimycin : A hydroxypiperidine that is deoxynojirimycin (duvoglustat) in which the amino hydrogen is replaced by a nonyl group. | hydroxypiperidine; tertiary amino compound | antiviral agent; EC 3.2.1.20 (alpha-glucosidase) inhibitor; EC 3.2.1.45 (glucosylceramidase) inhibitor |
1-(1-benzimidazolyl)-3-(1-cyclohex-3-enylmethoxy)-2-propanol | benzimidazoles | ||
2-(2-phenylethylthio)-3-pyridinecarboxylic acid | aromatic carboxylic acid; pyridines | ||
4-(2-furanylmethyl)-3-(phenylmethyl)-1H-1,2,4-triazole-5-thione | benzenes | ||
2-[[4-(4-chloroanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | dialkylarylamine; tertiary amino compound | ||
4-(benzenesulfonamido)-N-(5-ethyl-1,3,4-thiadiazol-2-yl)benzamide | sulfonamide | ||
tamoxifen | stilbenoid; tertiary amino compound | angiogenesis inhibitor; antineoplastic agent; bone density conservation agent; EC 1.2.3.1 (aldehyde oxidase) inhibitor; EC 2.7.11.13 (protein kinase C) inhibitor; estrogen antagonist; estrogen receptor antagonist; estrogen receptor modulator | |
4-oxido-3-(4-phenoxyphenyl)-4a,5,6,7,8,8a-hexahydroquinoxalin-1-ium 1-oxide | aromatic ether | ||
2-[[4-(3-methylanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | dialkylarylamine; tertiary amino compound | ||
N-(1-benzylpiperidin-4-yl)-2-(pyridin-3-yl)quinazolin-4-amine | N-(1-benzylpiperidin-4-yl)-2-(pyridin-3-yl)quinazolin-4-amine : A member of the class of quinazolines that is quinazoline which is substituted by a pyridin-3-yl group and a (1-benzylpiperidin-4-yl)nitrilo group at positions 2 and 4, respectively. | aromatic amine; piperidines; pyridines; quinazolines; secondary amino compound; tertiary amino compound | |
N-[4-methyl-2-(4-morpholinyl)-6-quinolinyl]cyclohexanecarboxamide | aminoquinoline | ||
andrographolide | carbobicyclic compound; gamma-lactone; labdane diterpenoid; primary alcohol; secondary alcohol | anti-HIV agent; anti-inflammatory drug; antineoplastic agent; metabolite | |
n-(5-adamantane-1-yl-methoxy-pentyl)deoxynojirimycin | |||
ogt2378 | sinbaglustat: an antineopl agent; structure in first source | ||
nnc 26-9100 | NNC 26-9100: structure in first source | aminopyridine | |
2-[[4-[2-[(2-methylpropan-2-yl)oxy]anilino]-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | aromatic ether | ||
2-[[4-(5-chloro-2-methoxyanilino)-6-(1-piperidinyl)-1,3,5-triazin-2-yl]amino]ethanol | methoxybenzenes; substituted aniline | ||
2-[[4-(4-methylanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | dialkylarylamine; tertiary amino compound | ||
2-[[4-(2-chloroanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | dialkylarylamine; tertiary amino compound | ||
2-[[4-(2-methoxyanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | methoxybenzenes; substituted aniline | ||
2-[[4-(3-methoxyanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | methoxybenzenes; substituted aniline | ||
2-[[4-(4-methoxyanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | methoxybenzenes; substituted aniline | ||
2-[[4-(2-hydroxyethylamino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]phenol | dialkylarylamine; tertiary amino compound | ||
2-[[4-(2-phenoxyanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | aromatic ether | ||
2-[[4-(1-pyrrolidinyl)-6-[2-(trifluoromethoxy)anilino]-1,3,5-triazin-2-yl]amino]ethanol | aromatic ether | ||
2-[[4-(5-chloro-2-ethoxyanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | aromatic ether | ||
2-[[4-(5-chloro-2-propan-2-yloxyanilino)-6-(1-pyrrolidinyl)-1,3,5-triazin-2-yl]amino]ethanol | aromatic ether |