Physiological roles of PKB/Akt isoforms in development and disease

PKB (protein kinase B, also known as Akt) is a serine/threonine protein kinase that is important in various signalling cascades and acts as a major signal transducer downstream of activated phosphoinositide 3-kinase. There are three closely related isoforms of PKB in mammalian cells, PKBa (Akt1), POP (Akt2) and PKBy (Akt3), and this review discusses recent advances in our understanding of the functions of these isoforms in the regulation of adipocyte differentiation, glucose homoeostasis and tumour development.