Moonlighting Proteins of Human and Some Other Eukaryotes. Evolutionary Aspects

This review presents materials on formation of the concept of moonlighting proteins and general characteristics of different similar proteins. It is noted that the concept under consideration is based on the data on the existence in different organisms of individual genes, protein products of which have not one, but at least two fundamentally different functions, for example, depending on cellular or extracellular location. An important feature of these proteins is that their functions can be switched. As a result, in different cellular compartments or outside the cells, as well as under a number of other circumstances, one of the possible functions can be carried out, and under other conditions, another. It is emphasized that the significant interest in moonlighting proteins is due to the fact that information is currently accumulating about their involvement in many vital molecular processes (glycolysis, translation, transcription, replication, etc.). Alternative hypotheses on the evolutionary origin of moonlighting proteins are discussed.