TLR3 Products

Description

Toll-like receptor 3 (TLR3) is a type I transmembrane glycoprotein that contributes to the innate immune response, recognizing distinct pathogen-associate molecular patterns (PAMPs) and damage-associate molecular patterns (DAMPs) (1,2). The TLR family member TLR3 specifically recognizes and binds double-stranded RNA (dsRNA) from viruses and the synthetic analog polyriboinosinic:polyribocytidylic acid (poly(I:C)) (1-5). TLR3 is typically expressed in the endosomes of innate immune cells including macrophages, natural killer (NK) cells, and dendritic cells (DCs) (1-5). TLR3 is also localized on the cell surface of fibroblasts, epithelial cells, and vascular endothelial cells (1-5). The human TLR3 protein is 904 amino acids (aa) in length with a theoretical molecular weight (MW) of 104 kDa (6). It consists of a 23 aa signal sequence, a horseshoe-shaped 681 aa extracellular domain (ECD) containing 23 leucine-rich repeats (LRRs), a 21 aa helical transmembrane domain, and a 179 aa cytoplasmic region containing a Toll/IL-1 receptor (TIR) domain (1,6). Upon ligand binding, TLR3-ECD dimerizes and the adapter protein TIR-domain-containing adapter inducing interferon-beta (TRIF/TICAM1) is recruited (1-5). TRIF interacts with tumor necrosis factor receptor-associated factor 3 (TRAF3) and TRAF6 and results in a signal transduction cascade involving activation of transcription factors interferon regulatory factor 3 (IRF3), IRF7, nuclear factor-kappaB (NF-kappaB), and activation protein-1 (AP-1) (1-5). Transcription factors translocate to the nucleus, driving type I interferon (IFN) production, secretion of pro-inflammatory cytokines, and tumor regression (1-5). Furthermore, TRIF can also interact with receptor-interacting serine-threonine kinase 1 (RIP1) and RIP3 leading to reactive oxygen species (ROS) production and apoptosis (1,2,5). Conversely, NF-kappaB transcription can also promote chemokine production and promote the WNT pathway associated with stemness and pro-tumorigenic properties (1,5).

Given the role of TLR3 in immune response, its expression or dysfunction has been associated with a number of pathologies from chronic inflammation to autoimmune disorders and cancer (1-5,7). TLR3 is expressed in many cancer types, often related to viral infection, such as cervical cancer, hepatocellular carcinoma (HCC), melanoma, breast cancer, and prostate cancer (1,5). TLR3 signaling has a dual role in cancer, either contributing to pro- or anti-tumor properties depending on the type of cancer (1,5). Therapeutic targeting the TLR3 signaling pathway is under investigation. TLR3 inhibitors or antagonists are being studied for the treatment autoimmune and inflammatory disorders such as of sepsis and atherosclerosis (2,8). TLR3 agonists, either alone or in combination with immune checkpoint inhibitors or therapeutic agents, are being studied as immunotherapeutic treatments of many cancers such as colorectal cancer, prostate cancer, and melanoma (7).

References

1. Zheng X, Li S, Yang H. Roles of Toll-Like Receptor 3 in Human Tumors. Front Immunol. 2021;12:667454. https://doi.org/10.3389/fimmu.2021.667454

2. Zhuang C, Chen R, Zheng Z, Lu J, Hong C. Toll-Like Receptor 3 in Cardiovascular Diseases. Heart Lung Circ. 2022;S1443-9506(22)00080-4. https://doi.org/10.1016/j.hlc.2022.02.012

3. Bianchi F, Pretto S, Tagliabue E, Balsari A, Sfondrini L. Exploiting poly(I:C) to induce cancer cell apoptosis. Cancer Biol Ther. 2017;18(10):747-756. https://doi.org/10.1080/15384047.2017.1373220

4. Matsumoto M, Seya T. TLR3: interferon induction by double-stranded RNA including poly(I:C). Adv Drug Deliv Rev. 2008;60(7):805-812. https://doi.org/10.1016/j.addr.2007.11.005

5. Muresan XM, Bouchal J, Culig Z, Soucek K. Toll-Like Receptor 3 in Solid Cancer and Therapy Resistance. Cancers (Basel). 2020;12(11):3227. https://doi.org/10.3390/cancers12113227

6. Uniprot (O15455)

7. Le Naour J, Galluzzi L, Zitvogel L, Kroemer G, Vacchelli E. Trial watch: TLR3 agonists in cancer therapy. Oncoimmunology. 2020;9(1):1771143. https://doi.org/10.1080/2162402X.2020.1771143

8. Gao W, Xiong Y, Li Q, Yang H. Inhibition of Toll-Like Receptor Signaling as a Promising Therapy for Inflammatory Diseases: A Journey from Molecular to Nano Therapeutics. Front Physiol. 2017;8:508. https://doi.org/10.3389/fphys.2017.00508

Bioinformatics

Entrez	142980 Mouse 364594 Rat 7098 Human
Uniprot	AAH59372.1 Human AAH94737.1 Human NP_003256 Human O15455 Human
Product By Gene ID	7098
Alternate Names	CD283 antigen CD283 toll-like receptor 3

Research Areas for TLR3

Find related products by research area and learn more about each of the different research areas below.

Cytokine Research
Immune System Diseases
Immunology
Innate Immunity
Signal Transduction
Toll-Like Receptors

Related TLR3 Blog Posts

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The role of TLR4 in breast cancer Toll like receptors (TLRs) are highly conserved proteins that are first known for their role in pathogen recognition and immune response activation.  In order to elicit the necessary immune response in reaction to a foreign pathogen, TLRs trigger cy...    Read more.

TRIF/TICAM1 and mitochondrial dynamics in the innate immune response TRIF, also known as toll like receptor adaptor molecule 1 or TICAM1, is known for its role in invading foreign pathogens as part of our innate immune response. TRIF/TICAM1 is a TIR-domain adaptor protein (toll/interleukin-1 receptor) that interacts...    Read more.

The role of STING/TMEM173 in gamma and encephalitis Herpes Simplex Virus (HSV) Stimulator of interferon genes (STING), also known as TMEM173, promotes the production of the interferon’s IFN-alpha and IFN-beta.  STING possesses three functional domains: a cytoplasmic C-terminal tail, a central globular domain, and four N-...    Read more.

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