Target type: biologicalprocess
Any process that modulates the frequency, rate, or extent of toll-like receptor 4 signaling pathway. [GOC:add, PMID:16551253, PMID:17328678]
Toll-like receptor 4 (TLR4) signaling is a crucial innate immune pathway that plays a critical role in recognizing and responding to invading pathogens, primarily Gram-negative bacteria. This intricate process involves a cascade of molecular events that ultimately trigger the activation of downstream signaling pathways, leading to the production of pro-inflammatory cytokines and the induction of immune responses.
The initiation of TLR4 signaling begins with the recognition of pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharide (LPS), a major component of the outer membrane of Gram-negative bacteria. LPS binds to TLR4, which is typically expressed on the surface of immune cells like macrophages, dendritic cells, and neutrophils. This binding event brings together TLR4 and its associated adaptor proteins, including myeloid differentiation factor 88 (MyD88) and TIR domain-containing adaptor protein inducing interferon-β (TRIF).
MyD88-dependent pathway: The MyD88-dependent pathway is the primary signaling pathway activated by TLR4. Upon LPS binding, MyD88 recruits the interleukin-1 receptor-associated kinase (IRAK) family members, including IRAK1 and IRAK4, to the TLR4 complex. IRAK4 then phosphorylates and activates IRAK1, which in turn activates the downstream signaling molecule tumor necrosis factor receptor-associated factor 6 (TRAF6). TRAF6 activates the ubiquitin ligase complex, leading to the activation of the transforming growth factor-β-activated kinase 1 (TAK1).
TAK1, once activated, phosphorylates and activates the IκB kinase (IKK) complex, leading to the phosphorylation and degradation of IκBα, an inhibitor of nuclear factor κB (NF-κB). The release of NF-κB allows it to translocate into the nucleus, where it activates the transcription of genes encoding pro-inflammatory cytokines, including tumor necrosis factor α (TNFα), interleukin 6 (IL-6), and interleukin 1β (IL-1β). These cytokines play a critical role in initiating and amplifying the inflammatory response.
TRIF-dependent pathway: The TRIF-dependent pathway is activated in response to prolonged or high-intensity TLR4 stimulation. TRIF binds to TLR4 and recruits the adaptor protein TRIF-related adaptor molecule (TRAM). The TRIF-TRAM complex activates the downstream signaling molecule TRAF3, leading to the activation of the transcription factors interferon regulatory factor 3 (IRF3) and nuclear factor κB (NF-κB). IRF3 activation leads to the production of type I interferons (IFNα/β), which are crucial for antiviral responses. NF-κB activation, as described above, leads to the production of pro-inflammatory cytokines.
Regulation of TLR4 signaling: TLR4 signaling is tightly regulated to prevent excessive inflammation and tissue damage. This regulation occurs at multiple levels, including:
* Negative regulators: TLR4 signaling is downregulated by a variety of negative regulators, including the suppressor of cytokine signaling (SOCS) proteins, IRAK-M, and A20. These molecules inhibit the activation of downstream signaling components or promote the degradation of signaling intermediates.
* Receptor internalization: Upon activation, TLR4 is internalized into endosomes, which limits its ability to activate signaling.
* Feedback loops: TLR4 signaling can induce the expression of negative regulators, such as SOCS proteins, which act as feedback mechanisms to dampen the signaling response.
The regulation of TLR4 signaling is crucial for maintaining immune homeostasis. Dysregulation of this pathway can contribute to the development of inflammatory diseases, such as sepsis, arthritis, and inflammatory bowel disease. Conversely, insufficient TLR4 signaling can impair immune defenses against pathogens and increase susceptibility to infections.
Understanding the intricate mechanisms of TLR4 signaling is essential for developing novel therapeutic strategies to modulate immune responses in various inflammatory and infectious diseases.'
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Protein | Definition | Taxonomy |
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Phosphatidylinositol 3-kinase regulatory subunit alpha | A phosphatidylinositol 3-kinase regulatory subunit alpha that is encoded in the genome of human. [PRO:DNx] | Homo sapiens (human) |
Compound | Definition | Classes | Roles |
---|---|---|---|
2-(4-morpholinyl)-8-phenyl-4h-1-benzopyran-4-one | 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one: specific inhibitor of phosphatidylinositol 3-kinase; structure in first source | chromones; morpholines; organochlorine compound | autophagy inhibitor; EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor; geroprotector |
vorinostat | vorinostat : A dicarboxylic acid diamide comprising suberic (octanedioic) acid coupled to aniline and hydroxylamine. A histone deacetylase inhibitor, it is marketed under the name Zolinza for the treatment of cutaneous T cell lymphoma (CTCL). Vorinostat: A hydroxamic acid and anilide derivative that acts as a HISTONE DEACETYLASE inhibitor. It is used in the treatment of CUTANEOUS T-CELL LYMPHOMA and SEZARY SYNDROME. | dicarboxylic acid diamide; hydroxamic acid | antineoplastic agent; apoptosis inducer; EC 3.5.1.98 (histone deacetylase) inhibitor |
whi p180 | |||
wortmannin | acetate ester; cyclic ketone; delta-lactone; organic heteropentacyclic compound | anticoronaviral agent; antineoplastic agent; autophagy inhibitor; EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor; geroprotector; Penicillium metabolite; radiosensitizing agent | |
quercetin | 7-hydroxyflavonol; pentahydroxyflavone | antibacterial agent; antineoplastic agent; antioxidant; Aurora kinase inhibitor; chelator; EC 1.10.99.2 [ribosyldihydronicotinamide dehydrogenase (quinone)] inhibitor; geroprotector; phytoestrogen; plant metabolite; protein kinase inhibitor; radical scavenger | |
panobinostat | panobinostat : A hydroxamic acid obtained by formal condensation of the carboxy group of (2E)-3-[4-({[2-(2-methylindol-3-yl)ethyl]amino}methyl)phenyl]prop-2-enoic acid with the amino group of hydroxylamine. A histone deacetylase inhibitor used (as its lactate salt) in combination with bortezomib and dexamethasone for the treatment of multiple myeloma. Panobinostat: An indole and hydroxamic acid derivative that acts as a HISTONE DEACETYLASE inhibitor. It is used as an antineoplastic agent in combination with BORTEZOMIB and DEXAMETHASONE for the treatment of MULTIPLE MYELOMA. | cinnamamides; hydroxamic acid; methylindole; secondary amino compound | angiogenesis modulating agent; antineoplastic agent; EC 3.5.1.98 (histone deacetylase) inhibitor |
nu 7026 | 2-(morpholin-4-yl)benzo(h)chromen-4-one: a radiosensitizing agent that inhibits DNA-dependent protein kinase; structure in first source | organic heterotricyclic compound; organooxygen compound | |
pi103 | PI103: pyridofuropyrimidine antineoplastic; a potent inhibitor of class I phosphatidylinositide 3-kinases (PI3K); structure in first soruce | aromatic amine; morpholines; organic heterotricyclic compound; phenols; tertiary amino compound | antineoplastic agent; EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor; mTOR inhibitor |
PI3-Kinase alpha Inhibitor 2 | organic heterobicyclic compound; organonitrogen heterocyclic compound; organosulfur heterocyclic compound | ||
tgx 221 | TGX 221: a platelet aggregation inhibitor | pyridopyrimidine | |
ic 87114 | IC 87114: structure in first source | 6-aminopurines; biaryl; quinazolines | EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor |
tg100-115 | 3,3'-(2,4-diaminopteridine-6,7-diyl)diphenol: for treatment of ischemia reperfusion injury; structure in first source | pteridines | |
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 |
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 |
gsk 2126458 | omipalisib : A member of the class of quinolines that is quinoline which is substituted by pyridazin-4-yl and 5-[(2,4-difluorobenzene-1-sulfonyl)amino]-6-methoxypyridin-3-yl groups at positions 4 and 6, respectively. It is a highly potent inhibitor of PI3K and mTOR developed by GlaxoSmithKline and was previously in human phase 1 clinical trials for the treatment of idiopathic pulmonary fibrosis and solid tumors. omipalisib: inhibitor of mTOR protein | aromatic ether; difluorobenzene; pyridazines; pyridines; quinolines; sulfonamide | anticoronaviral agent; antineoplastic agent; autophagy inducer; EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor; mTOR inhibitor; radiosensitizing agent |
azd2014 | vistusertib: potent and selective dual mTORC1 and mTORC2 inhibitor; structure in first source | ||
(5-(2,4-bis((3s)-3-methylmorpholin-4-yl)pyrido(2,3-d)pyrimidin-7-yl)-2-methoxyphenyl)methanol | (5-(2,4-bis((3S)-3-methylmorpholin-4-yl)pyrido(2,3-d)pyrimidin-7-yl)-2-methoxyphenyl)methanol: a potent, selective, and orally bioavailable ATP-competitive mammalian target of rapamycin kinase inhibitor with in vitro and in vivo antitumor activity; structure in first source | benzyl alcohols; morpholines; pyridopyrimidine; tertiary amino compound | antineoplastic agent; apoptosis inducer; mTOR inhibitor |
4-[6-[4-(methoxycarbonylamino)phenyl]-4-(4-morpholinyl)-1-pyrazolo[3,4-d]pyrimidinyl]-1-piperidinecarboxylic acid methyl ester | WYE-354: an mTOR inhibitor; structure in first source | carbamate ester | |
vs-5584 | VS-5584: a highly selective PI3K/mTOR kinase inhibitor for the treatment of cancer | ||
etp-46321 | ETP-46321: inhibits PI3K alpha and PI3K delta; 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 |
ipi-145 | isoquinolines | ||
pf-4989216 | PF-4989216: inhibits phosphatidylinositol 3-kinase; structure in first source | ||
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 |
azd8186 | |||
hs-173 | |||
cudc-907 | |||
byl719 | proline derivative | ||
amg 511 | AMG 511: structure in first source | ||
vx-970 | berzosertib: an ATR kinase inhibitor | sulfonamide | |
bay 80-6946 | copanlisib : An imidazoquinazoline that is 2,3-dihydroimidazo[1,2-c]quinazoline substituted by (2-aminopyrimidine-5-carbonyl)amino, methoxy, and 3-(morpholin-4-yl)propoxy groups at positions 5, 7 and 8, respectively. It is a intravenous pan-class I PI3K inhibitor used for the treatment of relapsed follicular lymphoma in patients who have received at least 2 prior systemic therapies. copanlisib: an antineoplastic agent with PI3K inhibitory activity; structure in first source |