title: Melatonin: A Mitochondrial Targeting Molecule Involving Mitochondrial Protection and Dynamics.
abstract: Melatonin has been speculated to be mainly synthesized by mitochondria. This speculation is supported by the recent discovery that aralkylamineN-acetyltransferase/serotoninN-acetyltransferase (AANAT/SNAT) is localized in mitochondria of oocytes and the isolated mitochondria generate melatonin. We have also speculated that melatonin is a mitochondria-targeted antioxidant. It accumulates in mitochondria with high concentration against a concentration gradient. This is probably achieved by an active transportation via mitochondrial melatonin transporter(s). Melatonin protects mitochondria by scavenging reactive oxygen species (ROS), inhibiting the mitochondrial permeability transition pore (MPTP), and activating uncoupling proteins (UCPs). Thus, melatonin maintains the optimal mitochondrial membrane potential and preserves mitochondrial functions. In addition, mitochondrial biogenesis and dynamics is also regulated by melatonin. In most cases, melatonin reduces mitochondrial fission and elevates their fusion. Mitochondrial dynamics exhibit an oscillatory pattern which matches the melatonin circadian secretory rhythm in pinealeocytes and probably in other cells. Recently, melatonin has been found to promote mitophagy and improve homeostasis of mitochondria.
authors.affiliation: Department of Cell System and Anatomy, The University of Texas Health Science Center, San Antonio, TX 78229, USA. tan@uthscsa.edu.
authors.forename: Dun-Xian
authors.initials: DX
authors.lastname: Tan
authors.affiliation: Department of Cell System and Anatomy, The University of Texas Health Science Center, San Antonio, TX 78229, USA. lmanchester@stmarytx.edu.
authors.forename: Lucien C
authors.initials: LC
authors.lastname: Manchester
authors.affiliation: Department of Cell System and Anatomy, The University of Texas Health Science Center, San Antonio, TX 78229, USA. qinl@uthscsa.edu.
authors.forename: Lilan
authors.initials: L
authors.lastname: Qin
authors.affiliation: Department of Cell System and Anatomy, The University of Texas Health Science Center, San Antonio, TX 78229, USA. reiter@uthscsa.edu.
authors.forename: Russel J
authors.initials: RJ
authors.lastname: Reiter
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002940:Circadian Rhythm / Q000502:physiology*; D004789:Enzyme Activation; D006801:Humans; D008550:Melatonin / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000502:physiology*; D008928:Mitochondria / Q000378:metabolism*; D063154:Mitochondrial Dynamics / Q000502:physiology*; D033681:Mitochondrial Membrane Transport Proteins / Q000037:antagonists & inhibitors; D000083162:Mitochondrial Permeability Transition Pore; D000071245:Mitochondrial Uncoupling Proteins / Q000378:metabolism; D063306:Mitophagy / Q000502:physiology*; D010944:Plants; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D000071245:Mitochondrial Uncoupling Proteins; D017382:Reactive Oxygen Species; D008550:Melatonin
keywords: antioxidant; melatonin; mitochondria; mitochondrial dynamics; mitophagy