Download MendeleyStructures and interface mapping of the TIR domain-containing adaptor molecules involved in interferon signaling.
Enokizono, Y., Kumeta, H., Funami, K., Horiuchi, M., Sarmiento, J., Yamashita, K., Standley, D.M., Matsumoto, M., Seya, T., Inagaki, F.(2013) Proc Natl Acad Sci U S A 110: 19908-19913
- PubMed: 24255114
- DOI: https://doi.org/10.1073/pnas.1222811110
- Primary Citation of Related Structures:
2M1W, 2M1X - PubMed Abstract:
Homotypic and heterotypic interactions between Toll/interleukin-1 receptor (TIR) domains in Toll-like receptors (TLRs) and downstream adaptors are essential to evoke innate immune responses. However, such oligomerization properties present intrinsic difficulties in structural studies of TIR domains. Here, using BB-loop mutations that disrupt homotypic interactions, we determined the structures of the monomeric TIR domain-containing adaptor molecule (TICAM)-1 and TICAM-2 TIR domains. Docking of the monomeric structures, together with yeast two hybrid-based mutagenesis assays, reveals that the homotypic interaction between TICAM-2 TIR is indispensable to present a scaffold for recruiting the monomeric moiety of the TICAM-1 TIR dimer. This result proposes a unique idea that oligomerization of upstream TIR domains is crucial for binding of downstream TIR domains. Furthermore, the bivalent nature of each TIR domain dimer can generate a large signaling complex under the activated TLRs, which would recruit downstream signaling molecules efficiently. This model is consistent with previous reports that BB-loop mutants completely abrogate downstream signaling.
Organizational Affiliation:
Department of Structural Biology, Faculty of Advanced Life Science, Hokkaido University, N-21, W-11, Kita-ku, Sapporo 001-0021, Japan.
