MAVS protein operates as a mitochondrial guardian that restricts SARS-CoV-2 and Japanese encephalitis virus replication through preserving organellar integrity, independent of traditional interferon immune signaling. The research demonstrates that MAVS stabilizes the translocase of the outer membrane complex, preventing mitochondrial fragmentation and depolarization while maintaining cellular energy production. This mitochondria-centered antiviral defense represents a fundamental shift in understanding how cells combat infection. The findings suggest that maintaining mitochondrial health could serve as a therapeutic target for viral diseases, potentially explaining why metabolic dysfunction increases infection susceptibility. The discovery that cellular powerhouses directly participate in viral restriction adds a new dimension to antiviral immunity beyond conventional immune responses. However, this preprint research awaits peer review, and the mechanisms require validation in human clinical contexts rather than laboratory cell cultures. The work appears paradigm-shifting by establishing mitochondrial integrity as a primary antiviral defense, potentially opening therapeutic avenues focused on mitochondrial support rather than solely immune system enhancement. Understanding this intrinsic cellular defense could inform strategies for preventing viral infections in vulnerable populations with compromised mitochondrial function.