Virus-induced signaling adaptor (VISA) is essential for host innate immune responses against double-stranded RNA viral infection and viral replication. It is an adaptor that activates the transcription factors nuclear factor kappaB (NF-kappaB) and interferon regulatory factor 3 (IRF3) that regulate the expression of type I interferons. The localization of VISA to the outer membrane of mitochondria and the cellular consequences of its activation implicate this protein in the cellular etiology of neurodegenerative disorders.