Neuroglobin is an oxygen-binding heme protein predominantly expressed in the nervous system in man and other vertebrates. Neuroglobin belongs to the globin superfamily. It displays the typical globin fold, but it shares little amino acid sequence similarity with vertebrate hemoglobins and myoglobins. Neuroglobin is highly conserved among vertebrates and is evolutionary related to the invertebrate nerve globins. In mouse and rat, neuroglobin is preferentially expressed in neuronal cells of the central and peripheral nervous systems, but also in some endocrine tissues. Neuroglobin is highly expressed in neurons of mammalian retina.
Neuroglobin may play an essential role in oxygen homeostasis of neuronal cells. Neuroglobin is thought to protect neurons from hypoxic-ischemic injury as suggested by its increased expression under hypoxic conditions in- vitro as well as in focal cerebral ischemia in vivo. Neuronal survival after hypoxia decreased when neuroglobin expression is inhibited by antisense oligonucleotide and enhanced by neuroglobin overexpression. Its distribution correlates with the subcellular localization of mitochondria and with oxygen demands, possibly linking neuroglobin to cellular respiration.
