Transcriptional regulation of the Ras-related protein TC21/R-Ras2 in endothelial cells.

Applying an RNA display strategy to identify genes of autocrine activated endothelial cells, we identified among others the Ras-related protein TC21/R-Ras2 as a differentially expressed gene of bovine aortic endothelial cells (BAEC). Migrating BAEC express prominently upregulated steady state levels of TC21/R-Ras2 mRNA (Northern blot, in situ hybridization) and protein (Western blot). Growth factor stimulation identified TC21/R-Ras2 as aFGF, bFGF, and EGF inducible molecule of BAEC. Exposure to actinomycin D revealed a half life time of TC21/R-Ras2 mRNA of > 2 h. These results strongly suggest that transcriptional regulation of Ras molecules contributes to their signal transduction capacity and a possible role of TC21/R-Ras2 in the signal transduction of autocrine activated endothelial cells.