Protein / target
Toll-like receptor 4
Protein at a glance
Biological role
Lipopolysaccharide immune receptor
Strongest disease association
Major depressive disorder
Therapeutic position
Clinically advancing target
Research activity
Emerging research
Derived from structured UniProt, Open Targets and literature data on this page.
Protein profile
Canonical identity and biological annotation from UniProt.
Function overview
Transmembrane receptor that functions as a pattern recognition receptor recognizing pathogen- and damage-associated molecular patterns (PAMPs and DAMPs) to induce innate immune responses via downstream signaling pathways.
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Transmembrane receptor that functions as a pattern recognition receptor recognizing pathogen- and damage-associated molecular patterns (PAMPs and DAMPs) to induce innate immune responses via downstream signaling pathways (PubMed:10835634, PubMed:15809303, PubMed:16622205, PubMed:17292937, PubMed:17478729, PubMed:20037584, PubMed:20711192, PubMed:23880187, PubMed:27022195, PubMed:29038465, PubMed:17803912, PubMed:15852007). At the plasma membrane, cooperates with LY96 to mediate the innate immune response to bacterial lipopolysaccharide (LPS) (PubMed:27022195). Also involved in LPS-independent inflammatory responses triggered by free fatty acids, such as palmitate, and Ni(2+) (PubMed:20711192). Mechanistically, acts via MYD88, TIRAP and TRAF6, leading to NF-kappa-B activation, cytokine secretion and the inflammatory response (PubMed:10835634, PubMed:21393102, PubMed:27022195, PubMed:36945827, PubMed:9237759). Alternatively, CD14-mediated TLR4 internalization via endocytosis is associated with the initiation of a MYD88-independent signaling via the TICAM1-TBK1-IRF3 axis leading to type I interferon production (PubMed:14517278). In addition to the secretion of proinflammatory cytokines, initiates the activation of NLRP3 inflammasome and formation of a positive feedback loop between autophagy and NF-kappa-B signaling cascade (PubMed:32894580). In complex with TLR6, promotes inflammation in monocytes/macrophages by associating with TLR6 and the receptor CD86 (PubMed:23880187). Upon ligand binding, such as oxLDL or amyloid-beta 42, the TLR4:TLR6 complex is internalized and triggers inflammatory response, leading to NF-kappa-B-dependent production of CXCL1, CXCL2 and CCL9 cytokines, via MYD88 signaling pathway, and CCL5 cytokine, via TICAM1 signaling pathway (PubMed:23880187). In myeloid dendritic cells, vesicular stomatitis virus glycoprotein G but not LPS promotes the activation of IRF7, leading to type I IFN production in a CD14-dependent manner (PubMed:15265881, PubMed:23880187). Required for the migration-promoting effects of ZG16B/PAUF on pancreatic cancer cells
Subcellular location
Domains and Gene Ontology detail (78)Hide
Domains & features
Gene Ontology
- Ccell surface
- Ccytoplasm
- Cearly endosome
- Cendosome membrane
- Cexternal side of plasma membrane
- Clipopolysaccharide receptor complex
- Cperinuclear region of cytoplasm
- Cphagocytic cup
- Cplasma membrane
- Creceptor complex
- Cruffle
- Famyloid-beta binding
Biological roles
What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.
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Lipid & lipoprotein metabolism
- ·Transmembrane receptor that functions as a pattern recognition receptor recognizing path…
- ·cellular response to oxidised low-density lipoprotein particle stimulus
Immune signalling
- ·Transmembrane receptor that functions as a pattern recognition receptor recognizing path…
- ·immune response
- ·inflammatory response
- ·innate immune response
Transcriptional regulation
- ·positive regulation of gene expression
- ·positive regulation of transcription by RNA polymerase II
Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.
Translational evidence
Why this target matters therapeutically, strongest evidence first. Disease associations are gene-level (via the gene that encodes this protein) and open into the full confidence synthesis; the development universe, tractability and safety annotations are target-level, from Open Targets.
Strongest disease associations · via encoding gene TLR4
Gene-level evidence surfaced through the gene TLR4 that encodes this protein — not a direct protein–disease relationship. Ranked by Forefront's causal-directness weighting, so genetically- and clinically-evidenced diseases lead over ones that merely share the literature.
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The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the per-type scores above show the calculation.
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Drug development
3 compounds recorded · 3 in clinical development
View all recorded compounds (3)Hide
Open Targets known-drugs universe. Drug name and highest clinical stage only — the disease relationship is NOT read from this slice (it carries trial-context noise); approved indications come from the canonical graph above.
Tractability
Small molecules — Strong
Antibodies — Emerging
Protein degraders — Emerging
View underlying tractability evidence (10)Hide
Raw Open Targets tractability assessment buckets, by modality.
Safety-related annotations
Terms indexed against this target in Open Targets' safety data, with their datasource. These are annotations, not causal claims: the direction of effect (whether activation or inhibition is implicated), species and evidence strength are not captured here, so an entry does not mean that modulating this target is known to cause that condition.
Research activity
Papers linked directly to this protein. This is the protein's own literature — descriptor-derived papers are kept separate below.
Most cited
Recent
Europe PMC papers linked directly to this protein.