One signal that is overactivated in a wide range of tumour types is the production of a phospholipid, phosphatidylinositol (3,4,5) trisphosphate, by phosphatidylinositol 3-kinase (PI3K) This lipid and the protein kinase that is activated by it — AKT — trigger a cascade of responses, from cell growth and proliferation to survival and motility, that drive tumour progression Small-molecule therapeutics that block PI3K signalling might deal a severe blow to cancer cells by blocking many aspects of the tumour-cell phenotype

The phosphatidylinositol 3-Kinase AKT pathway in human cancer.

In certain aspects, the invention relates to methods for identifying compounds which modulate Akt activity mediated by the rictor-mTOR complex and methods for treating or preventing a disorder that is associated with aberrant Akt activity.

http://science.sciencemag.org/content/sci/307/5712/1098.full.pdf

Phosphorylation and regulation of Akt/PKB by the rictor-mTOR complex

Physiologically important cell-signalling networks are complex, and contain several points of regulation, signal divergence and crosstalk with other signalling cascades. Here, we use the concept of 'critical nodes' to define the important junctions in these pathways and illustrate their unique role using insulin signalling as a model system.

Critical nodes in signalling pathways: Insights into insulin action

AKT/PKB Signaling: Navigating the Network

The mammalian heart is a dynamic organ that can grow and change to accommodate alterations in its workload. During development and in response to physiological stimuli or pathological insults, the heart undergoes hypertrophic enlargement, which is characterized by an increase in the size of individual cardiac myocytes. Recent findings in genetically modified animal models implicate important intermediate signal-transduction pathways in the coordination of heart growth following physiological and pathological stimulation.

Regulation of cardiac hypertrophy by intracellular signalling pathways

The serine/threonine kinase Akt has been implicated in the control of cell survival and metabolism. Here we report the disruption of the most ubiquitously expressed member of the akt family of genes, akt1, in the mouse. Akt1−/− mice are viable but smaller when compared to wild-type littermates. In addition, the life span of Akt1−/− mice, upon exposure to genotoxic stress, is shorter. However, Akt1−/− mice do not display a diabetic phenotype. Increased spontaneous apoptosis in testes, and attenuation of spermatogenesis is observed in Akt1−/− male mice. Increased spontaneous apoptosis is also observed in the thymi of Akt1−/− mice, and Akt1−/− thymocytes are more sensitive to apoptosis induced by γ-irradiation and dexamethasone. Finally, Akt1−/− mouse embryo fibroblasts (MEFs) are more susceptible to apoptosis induced by TNF, anti-Fas, UV irradiation, and serum withdrawal.

/pdf/growth-retardation-and-increased-apoptosis-in-mice-with-4nyv4isjm3.pdf

Wei Weng

Papers

Growth retardation and increased apoptosis in mice with homozygous disruption of the akt1 gene