Phosphatidylinositol (PI) 3-kinase is a cytoplasmic signaling molecule that is recruited to activated growth factor receptors after growth factor stimulation of cells. Activation of PI 3-kinase results in increased intracellular levels of 3' phosphorylated inositol phospholipids and the induction of signaling responses, including the activation of the protein kinase Akt, which is also known as RAC-PK or PKB. We tested the possibility that the phospholipid products of PI 3-kinase directly mediate the activation of Akt. We have previously described a constitutively active PI 3-kinase, p110, which can stimulate Akt activity. We used purified p110 protein to generate a series of 3' phosphorylated inositol phospholipids and tested whether any of these lipids could activate Akt in vitro. Phospholipid vesicles containing PI3,4 bisphosphate (P2) specifically activated Akt in vitro. By contrast, the presence of phospholipid vesicles containing PI3P or PI3,4,5P3 failed to increase the kinase activity of Akt. Akt could also be activated by synthetic dipalmitoylated PI3,4P2 or after enzymatic conversion of PI3,4,5P3 into PI3,4P2 with the signaling inositol polyphosphate 5' phosphatase SIP. We show that PI3,4P2-mediated activation is dependent on a functional pleckstrin homology domain in Akt, since a point mutation in the pleckstrin homology domain abrogated the response to PI3,4P2. Our findings show that a phospholipid product of PI 3-kinase can directly stimulate an enzyme known to be an important mediator of PI 3-kinase signaling.

The TNF family is involved in the regulation of the immune system, and its members have been implicated in a variety of biological events such as apoptosis, cell proliferation, differentiation and survival. Here we present a new member of the TNF family, tumor necrosis factor super family member 20 (TNFSF20) that we have identified from the expressed sequence tag (EST) database and characterized. The human protein is a 285 amino acid long type II transmembrane protein and is 19% homologous to TNF in its extra-cellular domain. TNFSF20 is expressed at the surface of antigen presenting cells such as cells of the macrophagemonocyte lineage and dendritic cells. After treatment with bacterial lipopolysaccharide (LPS), TNFSF20 expression is downregulated at the surface of the expresssing cells, suggesting that the membrane-bound protein gets cleaved, and that a soluble factor is released in the extra-cellular compartment. The soluble form of the recombinant TNFSF20 induces proliferation of resting peripheral blood monocytes (PBMC) and cell death of activated lymphocytes. TNFSF20 might therefore play a critical role in the regulation of cell-mediated immune responses.

The ISB Cancer Genomics Cloud (ISB-CGC) is one of three pilot projects funded by the National Cancer Institute to explore new approaches to computing on large cancer datasets in a cloud environment. With a focus on Data as a Service, the ISB-CGC offers multiple avenues for accessing and analyzing The Cancer Genome Atlas, TARGET, and other important references such as GENCODE and COSMIC using the Google Cloud Platform. The open approach allows researchers to choose approaches best suited to the task at hand: from analyzing terabytes of data using complex workflows to developing new analysis methods in common languages such as Python, R, and SQL; to using an interactive web application to create synthetic patient cohorts and to explore the wealth of available genomic data. Links to resources and documentation can be found at www.isb-cgc.org. Cancer Res; 77(21); e7–10. ©2017 AACR.