Toll-like receptor (TLR) and Myeloid differentiation primary response 88 (MyD88) signaling complex (TLR/MyD88)

The Toll-like receptor (TLR) and Myeloid differentiation primary response 88 (MyD88) signaling complex is a cornerstone of the innate immune system, responsible for detecting a wide array of pathogens (O'Neill et al., 2013, Nat Rev Immunol). TLRs are transmembrane pattern recognition receptors that identify conserved microbial structures, while MyD88 serves as a near-universal adapter protein that bridges these receptors to downstream signaling kinases (Deguine & Barton, 2014, F1000Prime Rep). Upon ligand binding, MyD88 is recruited to the TLR's cytoplasmic TIR domain, triggering a cascade that activates NF-kappaB and MAP kinases to induce pro-inflammatory cytokine production (Kawai & Akira, 2010, Nat Immunol). Aberrant activation of this pathway is a key driver in chronic inflammatory diseases, sepsis, and autoimmune conditions like systemic lupus erythematosus (Saikh, 2021, Front Immunol). Additionally, specific mutations in the MYD88 gene, most notably L265P, lead to constitutive pathway activation and are diagnostic hallmarks of B-cell malignancies such as Waldenström macroglobulinemia (Treon et al., 2012, N Engl J Med). Pharmacological modulation of this axis includes TLR agonists used as vaccine adjuvants or cancer immunotherapies, and MyD88 inhibitors currently under investigation for treating inflammatory and neoplastic diseases (Anwar et al., 2019, Front Immunol).

Other names

TLR-MyD88 signaling axisMyD88-dependent Toll-like receptor pathwayToll-interleukin-1 receptor domain-containing adapter protein signalingTLR/MyD88 pathway

Drugs targeting this complex function as either agonists to stimulate the innate immune response for antiviral or antineoplastic therapy, or as antagonists/inhibitors to block the recruitment of MyD88 to TLRs, thereby suppressing pathological pro-inflammatory signaling in autoimmune and inflammatory disorders.