Endosomal receptor that plays a key role in innate and adaptive immunity. Controls host immune response against pathogens through recognition of RNA degradation products specific to microorganisms that are initially processed by RNASET2. Upon binding to agonists, undergoes dimerization that brings TIR domains from the two molecules into direct contact, leading to the recruitment of TIR-containing downstream adapter MYD88 through homotypic interaction. In turn, the Myddosome signaling complex is formed involving IRAK4, IRAK1, TRAF6, TRAF3 leading to activation of downstream transcription factors NF-kappa-B and IRF7 to induce pro-inflammatory cytokines and interferons, respectively. Activated by RNAs having enough uridines. Homodimer (By similarity). Interacts with MYD88 via their respective TIR domains (Probable). Interacts with UNC93B1 (PubMed:19451267). Interacts with BTK (By similarity). Interacts with SMPDL3B (PubMed:26095358). Endosomal localization confers distinctive proteolytic processing. Ubiquitinated by RNF216; leading to degradation by the proteasome. Proteolytic processing occurs in monocytes and monocyte-derived macrophages by both furin-like proprotein convertase and cathepsins. The cleavage is necessary for dimer formation and subsequent activation. Belongs to the Toll-like receptor family.