Nucleic acid-binding protein involved in innate immune response to DNA and RNA viruses (PubMed:30193849, PubMed:30135424). Binds DNA and RNA in the cytoplasm and acts by promoting recognition of viral nucleic acids by virus sensors, such as DDX58/RIG-I, IFIH1/MDA5 and CGAS (PubMed:30193849, PubMed:30135424). Acts as a co-sensor for recognition of double-stranded DNA (dsDNA) by cGAS in the cytoplasm, thereby playing a role in innate immune response to cytosolic dsDNA and DNA virus (By similarity). Binds dsDNA and probably acts by promoting sensing of dsDNA by CGAS, leading to enhance CGAS oligomerization and activation (By similarity). Promotes sensing of viral RNA by RIG-I-like receptors proteins DDX58/RIG-I and IFIH1/MDA5 via two mechanisms: binds double-stranded RNA (dsRNA), enhancing the binding of DDX58/RIG-I and IFIH1/MDA5 to dsRNA and promotes 'Lys-63'-linked ubiquitination and subsequent activation of DDX58/RIG-I and IFIH1/MDA5 (By similarity). Interacts with CGAS (By similarity). Interacts with DDX58/RIG-I (By similarity). Interacts with IFIH1/MDA5 (By similarity). Mice were born at the Mendelian ratio and do not show defects in development and immune cell differentiation (PubMed:30193849). Mice are however more susceptible to DNA and RNA virus infection (PubMed:30193849, PubMed:30135424).