Pesce Alessandra, Bolognesi Martino, Bocedi Alessio, Ascenzi Paolo, Dewilde Sylvia, Moens Luc, Hankeln Thomas, Burmester Thorsten
Department of Physics-INFM and Center for Excellence in Biomedical Research, University of Genova, Via Dodecaneso 33, I-16146 Genova, Italy.
EMBO Rep. 2002 Dec;3(12):1146-51. doi: 10.1093/embo-reports/kvf248.
Neuroglobin and cytoglobin are two recently discovered members of the vertebrate globin family. Both are intracellular proteins endowed with hexacoordinated heme-Fe atoms, in their ferrous and ferric forms, and display O2 affinities comparable with that of myoglobin. Neuroglobin, which is predominantly expressed in nerve cells, is thought to protect neurons from hypoxic-ischemic injury. It is of ancient evolutionary origin, and is homologous to nerve globins of invertebrates. Cytoglobin is expressed in many different tissues, although at varying levels. It shares common ancestry with myoglobin, and can be traced to early vertebrate evolution. The physiological roles of neuroglobin and cytoglobin are not completely understood. Although supplying cells with O2 is the likely function, it is also possible that both globins act as O2-consuming enzymes or as O2 sensors. Here, we review what is currently known about neuroglobin and cytoglobin in terms of their function, tissue distribution and relatedness to the well-known hemoglobin and myoglobin. Strikingly, the data reveal that O2 metabolism in cells is more complicated than was thought before, requiring unexpected O2-binding proteins with potentially novel functional features.
神经球蛋白和细胞球蛋白是脊椎动物球蛋白家族中最近发现的两个成员。二者均为细胞内蛋白质，其亚铁和高铁形式均含有六配位的血红素铁原子，并且其氧亲和力与肌红蛋白相当。主要在神经细胞中表达的神经球蛋白被认为可保护神经元免受缺氧缺血性损伤。它起源于古老的进化过程，与无脊椎动物的神经球蛋白同源。细胞球蛋白在许多不同组织中均有表达，不过表达水平各异。它与肌红蛋白有着共同的祖先，可追溯到早期脊椎动物的进化过程。神经球蛋白和细胞球蛋白的生理作用尚未完全明确。尽管为细胞提供氧气可能是其功能，但这两种球蛋白也有可能作为耗氧酶或氧气传感器发挥作用。在此，我们就神经球蛋白和细胞球蛋白目前已知的功能、组织分布以及与著名的血红蛋白和肌红蛋白的相关性进行综述。引人注目的是，数据显示细胞内的氧代谢比之前认为的更为复杂，需要具有潜在新功能特征的意外氧结合蛋白。
