Positively regulates Toll-like receptor signaling via TLR7, TLR9 and TLR13 in neutrophils and splenic macrophages (PubMed:25848864). Regulates TLR7 signaling by controlling ligand-induced recruitment of TLR7 from the endoplasmic reticulum to endosomes and lysosomes (PubMed:25848864). Positively regulates Toll-like receptor TLR9-induced production of inflammatory cytokines but is dispensable for IFNB1 production (PubMed:25848864). Involved in the anti-viral response to several viruses including influenza virus, vesicular stomatitis virus and cytomegalovirus (PubMed:25848864). Binds to late apoptotic, and necrotic cells, but not living or early apoptotic cells, but is not essential for uptake of dying cells by dendritic cells (DCs) (PubMed:22210914, PubMed:19155473, PubMed:25848864). Does not bind nucleic acids (PubMed:25848864). May participate in antigen presentation (PubMed:22210914). Interacts with TYROBP/DAP12. Predominantly expressed in spleen, with highest levels on selected populations of macrophages, including red pulp macrophages, and on subsets of dendritic cells (DC), mostly on CD8alpha(+) DC (at protein level) (PubMed:19155473, PubMed:22210914, PubMed:25848864). Also expressed on blood and spleen Ly6C(low) monocytes (at protein level) (PubMed:22210914). Not expressed on lymphocytes or granulocytes (at protein level) (PubMed:19155473, PubMed:22210914). Induced by synthetic TLR7 ligand gardiquimod (GRD) in cultured splenic macrophages. The cytoplasmic tail appears to be dispensable for TLR7-mediated signaling. No visible phenotype (PubMed:22210914). Mutant mice are born at the expected Mendelian frequency and are fertile and healthy (PubMed:22210914). In response to gardiquimod (GRD) or Resiquimod (R-848), 2 synthetic TLR7 ligands, levels of TNF, IL12B, IFNB1 and CXCL10 in splenic macrophages and in serum are severely reduced (PubMed:25848864). In response to CpG DNA, a TLR9 ligand, levels of TNF and IL12B but not IFNB1 and CXCL10 are severely reduced (PubMed:25848864). In response to infection with influenza virus (strain A/PuertoRico/8/34 (PR8)) the production of TNF, IL12B, IFNB1 and CXCL10 is severely impaired, the viral load is higher in the lungs, recovery after weight loss and survival are also impaired (PubMed:25848864). No defects in response to lipopolysaccharide (LPS) (PubMed:25848864). Reduced symptom severity in a mouse model for the autoimmune disease systemic lupus erythematosus (SLE) (PubMed:25848864).