Updated project metadata. Mitochondria are critical for metabolic homeostasis of the liver, and thus, mitochondrial dysfunction is a major cause of liver diseases. Optic atrophy 1 (OPA1) is a mitochondrial fusion protein that also plays a role in cristae shaping. Hence, the OPA1 gene disruption has been shown to cause mitochondrial dysfunction. However, the role of OPA1 in liver function is poorly understood. In this study, we deleted OPA1 in fully developed mouse liver and examined its effect.