PKB/Akt: a key mediator of cell proliferation, survival and insulin responses?

The serine/threonine protein kinase PKB (also known as Akt) is thought to b e a key mediator of signal transduction processes. The identification of PK B substrates and the role PKB phosphorylation plays in regulating these mol ecules have been a major focus of research in recent years. A recently deve loped motif-profile scoring algorithm that can be used to scan the genome f or potential PKB substrates is therefore a useful tool, although additional considerations, such as the evolutionary conservation of the phosphorylati on site, must also be taken into account. Recent evidence indicates that PK B plays a key role in cancer progression by stimulating cell proliferation and inhibiting apoptosis and is also probably a key mediator of insulin sig nalling. These findings indicate that PKB is likely to be a hot drug target for the treatment of cancer, diabetes and stroke. There are, however, a nu mber of pitfalls of methodologies currently employed to study PKB function, and therefore caution should be used in interpretation of such experiments .