Melatonin signaling in mitochondria extends beyond neurons and neuroprotection: Implications for angiogenesis and cardio/gastroprotection

We read with interest the paper of Suofu et al. (1), demonstrating that neuronal mitochondria produce melatonin, which upon binding to its melatonin type 1 (MT1) receptor on the mitochondrial membrane (MM) inhibits cytochrome c release, caspase activation, and apoptosis. We commend the authors on their thorough investigation but wish to point out some major questions: ( i ) Is the presence of the MT1 receptor in mitochondria limited to the...