Description
Akt [also known as PKB (Protein kinase B) is a family of serine/threonine kinases that plays an important role in signal transduction. There are three known isoforms of Akt in mammalian cells [Akt1 (alpha), Akt2 (beta) and Akt3 (gamma)]; Akt2 and Akt3 have 81% and 83% homology in amino acid sequences with Akt1, respectively. Numerous studies have revealed that the expression pattern of Akt1 and Akt2 is ubiquitous, whereas Akt3 is expressed predominantly in brain, heart, and kidney. Akt is activated by insulin and growth and survival factors. EGF-induced Akt3 activation was demonstrated by Ser-472 phosphorylation of Akt3 but in a restrictive fashion. A recent report suggests a contribution of Akt3 to the aggressive phenotype of human breast cancer, thus Akt seems to confer a growth advantage to tumor cells