Masahiro Yamamoto

MyD88 is a Toll/IL-1 receptor (TIR) domain-containing adapter common to signaling pathways via Toll-like receptor (TLR) family. However, accumulating evidence demonstrates the existence of a MyD88-independent pathway, which may explain unique biological responses of individual TLRs, particularly TLR3 and TLR4. TIR domain-containing adapter protein (TIRAP)/MyD88 adapter-like, a second adapter harboring the TIR domain, is essential for MyD88-dependent TLR2 and TLR4 signaling pathways, but not for

On microbial invasion, the host immediately evokes innate immune responses. Recent studies have demonstrated that Toll-like receptors (TLRs) play crucial roles in innate responses that lead not only to the clearance of pathogens but also to the efficient establishment of acquired immunity by directly detecting molecules from microbes. In terms of intracellular TLR-mediated signaling pathways, cytoplasmic adaptor molecules containing Toll/IL-1R (TIR) domains play important roles in inflammatory i

Infection by Toxoplasma gondii down-regulates the host innate immune responses, such as proinflammatory cytokine production, in a Stat3-dependent manner. A forward genetic approach recently demonstrated that the type II strain fails to suppress immune responses because of a potential defect in a highly polymorphic parasite-derived kinase, ROP16. We generated ROP16-deficient type I parasites by reverse genetics and found a severe defect in parasite-induced Stat3 activation, culminating in enhance

Toxoplasma gondii can infect homoeothermic animals including humans and cause lethal toxoplasmosis in immunocompromised individuals. When hosts are infected with T. gondii, the cells induce immune responses against T. gondii. The pathogen infection is recognized by immune sensors that directly detect T. gondii structural components, leading to production of pro-inflammatory cytokines and chemokines. Antigen-presenting cells such as macrophages and dendritic cells strongly activate T cells and in