Target type: biologicalprocess
The process of directing proteins towards the lysosome using signals contained within the protein. [GOC:curators]
Protein targeting to lysosomes is a complex and highly regulated process essential for maintaining cellular homeostasis. It involves the delivery of proteins, including soluble enzymes, transmembrane proteins, and receptors, from the trans-Golgi network (TGN) to the lysosome, where they are degraded or sorted for other cellular destinations. The process relies on a series of molecular signals embedded within the target proteins and the intricate machinery of the secretory pathway.
The journey begins with the synthesis of proteins destined for the lysosome on ribosomes attached to the endoplasmic reticulum (ER). These proteins typically possess a unique sorting signal known as a lysosomal targeting signal (LTS), which directs them to the lysosomal pathway. Several types of LTS have been identified, including:
1. **Mannose-6-phosphate (M6P) residues:** The most common and well-characterized LTS. M6P residues are added to lysosomal hydrolases in the Golgi apparatus, specifically in the cis-Golgi, through a series of enzymatic reactions. These residues are recognized by M6P receptors present on the TGN membrane.
2. **Other signals:** While M6P-mediated sorting is the dominant mechanism, other signals, including dileucine motifs, tyrosine-based signals, and GPI anchors, have also been identified and contribute to lysosomal targeting.
Once the proteins reach the TGN, they interact with the M6P receptors, initiating their journey to the lysosome. The M6P receptor-ligand complex moves through the TGN and is packaged into clathrin-coated vesicles. These vesicles bud off from the TGN and fuse with late endosomes, acidic compartments that serve as intermediates in the lysosomal pathway.
Inside the late endosomes, the acidic environment triggers the dissociation of the M6P receptor from the lysosomal hydrolases. The receptors cycle back to the TGN for further rounds of cargo transport, while the lysosomal enzymes are retained within the late endosomes.
Finally, the late endosomes mature into lysosomes, acidic organelles containing a diverse array of hydrolytic enzymes capable of degrading various cellular components, including proteins, lipids, and carbohydrates.
This intricate targeting process ensures the efficient delivery of lysosomal enzymes to their designated destination, enabling the lysosome to perform its critical role in cellular recycling and degradation. Defects in this pathway can lead to various lysosomal storage disorders, highlighting the importance of precise protein sorting for maintaining cellular homeostasis and preventing disease.'
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Protein | Definition | Taxonomy |
---|---|---|
N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase | An N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9UK23] | Homo sapiens (human) |
Sortilin | A sortilin that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q99523] | Homo sapiens (human) |
Phosphatidylinositol 3-kinase catalytic subunit type 3 | A phosphatidylinositol 3-kinase catalytic subunit type 3 that is encoded in the genome of human. [PRO:DNx] | Homo sapiens (human) |
Nuclear receptor coactivator 4 | A nuclear receptor coactivator 4 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q13772] | Homo sapiens (human) |
Ras-related protein Rab-7a | A Ras-related protein Rab-7a that is encoded in the genome of human. [PRO:DNx, UniProtKB:P51149] | Homo sapiens (human) |
Lutropin-choriogonadotropic hormone receptor | A lutropin-choriogonadotropic hormone receptor that is encoded in the genome of human. [PRO:WCB, UniProtKB:P22888] | Homo sapiens (human) |
Compound | Definition | Classes | Roles |
---|---|---|---|
sr 48692 | SR 48692: structure in first source; a neurotensin receptor-1 antagonist | N-acyl-amino acid | |
2-[[benzamido(sulfanylidene)methyl]amino]-5,5-dimethyl-4,7-dihydrothieno[2,3-c]pyran-3-carboxylic acid | CID1067700: a pan-GTPase inhibitor; structure in first source | thienopyran | |
ML162 | ML162 : A monochlorobenzene that is benzene substituted by (chloroacetyl){2-oxo-2-[(2-phenylethyl)amino]-1-(thiophen-2-yl)ethyl}amino, chloro and methoxy groups at positions 1, 3 and 4, respectively. It is a covalent inhibitor of glutathione peroxidase 4 (GPX4) that induces ferroptosis in cells. | monochlorobenzenes; monomethoxybenzene; organochlorine compound; secondary carboxamide; tertiary carboxamide; thiophenes | EC 1.11.1.9 (glutathione peroxidase) inhibitor; ferroptosis inducer |
n-acetylglucosaminono-1,5-lactone o-(phenylcarbamoyl)oxime | N-acetylglucosaminono-1,5-lactone O-(phenylcarbamoyl)oxime: structure given in first source | ||
lenvatinib | lenvatinib : A member of the class of quinolines that is the carboxamide of 4-{3-chloro-4-[(cyclopropylcarbamoyl)amino]phenoxy}-7-methoxyquinoline-6-carboxylic acid. A multi-kinase inhibitor and orphan drug used (as its mesylate salt) for the treatment of various types of thyroid cancer that do not respond to radioiodine. | aromatic amide; aromatic ether; cyclopropanes; monocarboxylic acid amide; monochlorobenzenes; phenylureas; quinolines | antineoplastic agent; EC 2.7.10.1 (receptor protein-tyrosine kinase) inhibitor; fibroblast growth factor receptor antagonist; orphan drug; vascular endothelial growth factor receptor antagonist |
org 41841 | Org 41841: structure in first source | pyrimidines; thienopyrimidine | |
PI3-Kinase alpha Inhibitor 2 | organic heterobicyclic compound; organonitrogen heterocyclic compound; organosulfur heterocyclic compound | ||
idelalisib | idelalisib : A member of the class of quinazolines that is 5-fluoro-3-phenylquinazolin-4-one in which the hydrogen at position 2 is replaced by a (1S)-1-(3H-purin-6-ylamino)propyl group. used for for the treatment of refractory indolent non-Hodgkin's lymphoma and relapsed chronic lymphocytic leukemia. idelalisib: an antineoplastic agent and p110delta inhibitor; structure in first source | aromatic amine; organofluorine compound; purines; quinazolines; secondary amino compound | antineoplastic agent; apoptosis inducer; EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor |
zstk474 | ZSTK-474 : A triamino-1,3,5-triazine that is 1,3,5-triazine in which two of the hydrogens have been replaced by morpholin-4-yl groups while the third hydrogen has been replaced by a 2-(difluoromethyl)benzimidazol-1-yl group. It is an inhibitor of phosphatidylinositol 3-kinase. | benzimidazoles; morpholines; organofluorine compound; triamino-1,3,5-triazine | antineoplastic agent; EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor |
dactolisib | dactolisib : An imidazoquinoline that is 3-methyl-2-oxo-2,3-dihydro-1H-imidazo[4,5-c]quinoline substituted at position 1 by a 4-(1-cyanoisopropyl)phenyl group and at position 8 by a quinolin-3-yl group. A dual PI3K/mTOR inhibitor used in cancer treatment. dactolisib: antineoplastic agent that inhibits both phosphatidylinositol 3-kinase and mTOR | imidazoquinoline; nitrile; quinolines; ring assembly; ureas | antineoplastic agent; EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor; mTOR inhibitor |
ku 60019 | |||
buparlisib | NVP-BKM120: a pan class I PI3 kinase inhibitor with antineoplastic activity; structure in first source | aminopyridine; aminopyrimidine; morpholines; organofluorine compound | antineoplastic agent; EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor |
gdc 0941 | pictrelisib : A sulfonamide composed of indazole, morpholine, and methylsulfonyl-substituted piperazine rings bound to a thienopyrimidine ring. | indazoles; morpholines; piperazines; sulfonamide; thienopyrimidine | EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor |
neurotensin | neurotensin, Tyr(11)-: RN given refers to parent cpd & (D)-isomer; RN for cpd without isomeric designation not avail 5/91 | peptide hormone | human metabolite; mitogen; neurotransmitter; vulnerary |
gdc 0980 | |||
azd2014 | vistusertib: potent and selective dual mTORC1 and mTORC2 inhibitor; structure in first source | ||
pki 587 | gedatolisib: inhibits both phosphatidylinositol 3-kinase and mTOR; structure in first source | ||
5-(4-amino-1-propan-2-yl-3-pyrazolo[3,4-d]pyrimidinyl)-1,3-benzoxazol-2-amine | sapanisertib: an mTOR inhibitor | benzoxazole | |
ch 5132799 | CH 5132799: structure in first source | ||
torin 1 | torin 1 : A member of the class of pyridoquinolines that is 9-(quinolin-3-yl)benzo[h][1,6]naphthyridin-2-one bearing an additional 4-(4-propionylpiperazin-1-yl)-3-(trifluoromethyl)phenyl substituent at position 1. It is a potent inhibitor of mTOR and exhibits anti-cancer properties. | N-acylpiperazine; N-arylpiperazine; organofluorine compound; pyridoquinoline; quinolines | antineoplastic agent; mTOR inhibitor |
gdc-0032 | |||
spautin-1 | |||
torin 2 | torin 2 : A member of the class of pyridoquinolines that is benzo[h][1,6]naphthyridin-2-one carrying additional 3-(trifluoromethyl)phenyl and 6-aminopyridin-3-yl substituents at positions 1 and 9 respectively. It is a potent inhibitor of mTOR and exhibits anti-cancer properties. | aminopyridine; organofluorine compound; primary amino compound; pyridoquinoline | antineoplastic agent; mTOR inhibitor |
cudc-907 | |||
sar245408 | |||
byl719 | proline derivative | ||
cep-32496 | agerafenib: inhibitor of RAF family kinases; structure in first source | ||
amg 511 | AMG 511: structure in first source | ||
cc-223 | |||
af38469 | |||
sar405 | SAR405: a Vps34 inhibitor with antineoplastic activity; structure in first source | ||
guanosine diphosphate | Guanosine Diphosphate: A guanine nucleotide containing two phosphate groups esterified to the sugar moiety. | guanosine 5'-phosphate; purine ribonucleoside 5'-diphosphate | Escherichia coli metabolite; mouse metabolite; uncoupling protein inhibitor |
guanosine triphosphate | Guanosine Triphosphate: Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety. | guanosine 5'-phosphate; purine ribonucleoside 5'-triphosphate | Escherichia coli metabolite; mouse metabolite; uncoupling protein inhibitor |