Another important challenge addressed in the last decade has been the deciphering of the roles of the two GSK-3 isozymes GSK-3 and GSK-3 . Over the last decade, there has been continuous progress in our understanding of the biology of the protein kinase GSK-3. Taking into consideration that the evolution of GSK-3 differs dramatically from that of GSK-3, it is important to deepen our understanding of the unique biochemical, structural, and biological properties of GSK-3, the isozyme that has been "historically" overlooked (in favor of GSK-3) [[1]]. [Extracted from the article]