The pivotal role of phosphatidylinositol 3-kinase-Akt signal transduction in virus survival

Over the course of evolution, viruses have developed the ability to modulate a variety of host cell signalling pathways. Inhibition of apoptosis, in particular, has become recognized as an important contributory factor in virus survival. Apoptotic inhibition contributes to the establishment of latent and chronic infections and has been implicated in viral oncogenesis. The phosphatidylinositol 3-kinase (Pl3K)-Akt pathway is utilized by many cell types for inhibition of apoptosis and cellular survival. Virus modulation of this pathway provides an alternative to the expression of viral oncogenes or the direct inhibition of pro-apoptotic proteins. It has become evident that many viruses require up-regulation of this pathway to sustain long-term infections and it is modulated, in some cases, by specific viral products to create an environment favourable for cellular transformation. In other cases, Pl3K-Akt signalling simply helps to create an environment favourable for virus replication and virion assembly. This review details the modulation and function of Pl3K-Akt signalling for virus survival.