Modulation of total Akt kinase by increased expression of a single isoform: requirement of the sphingosine-1-phosphate receptor, Edg3/S1P3, for the VEGF-dependent expression of Akt3 in primary endothelial cells
Abstract
Akt kinase is an important downstream effector of VEGF in primary endothelial cells (EC), promoting angiogenesis by increased cellular survival, motility and tubulogenesis. Akt1 is the founding member of a family of serine threonine kinases thought to have overlapping function. We sought to determine if other Akt family members were also regulated by VEGF in EC. We show that treatment of EC with the angiogenic inducers VEGF or sphingosine-1-phosphate (S1P) results in an increased stabilization of Akt3 mRNA, concurrent with a PI3 kinase-dependent, Akt1-independent increase in both the protein and its phosphorylation. Given the similarity of Akt3 regulation by VEGF and S1P, the sensitivity of VEGF stimulation to the Gi-protein uncoupling reagent, pertussis toxin was tested and shows that VEGF stimulation requires Gi-protein signaling. We show that the VEGF stimulates the expression of Edg3/S1P3 (S1P3) and that expression of this Gi-protein-coupled receptor is both sufficient and necessary for the expression of Akt3. Blockade of a single isoform does not overtly affect cellular function, whereas inhibition of both kinases results in an increase in apoptosis and a down-regulation of cyclin D3. These results suggest a model whereby ...Continue Reading
References
Citations
Cellular context-mediated Akt dynamics regulates MAP kinase signaling thresholds during angiogenesis
Related Concepts
Related Feeds
AKT Pathway
This feed focuses on the AKT serine/threonine kinase, which is an important signaling pathway involved in processes such as glucose metabolism and cell survival.
Arterial-Venous in Development & Disease
Arterial-venous development may play a crucial role in cardiovascular diseases. Here is the latest research.
Antisense Oligonucleotides: ND
This feed focuses on antisense oligonucleotide therapies such as Inotersen, Nusinursen, and Patisiran, in neurodegenerative diseases including amyotrophic lateral sclerosis.
Apoptosis
Apoptosis is a specific process that leads to programmed cell death through the activation of an evolutionary conserved intracellular pathway leading to pathognomic cellular changes distinct from cellular necrosis