Ras activation on the Golgi of T cells is mediated by the RasGRP1 guanine nucleotide exchange factor. Ras activation on the plasma membrane is kept in check by the GAP CAPRI. more detail
CD4+ splenocytes from a BALB/c mouse were transduced by nucleofection with CFP-H-Ras and YFP-RBD and stimulated (bottom) by cross-linking the T cell receptor. Accumulation of the YFP-RBD biosensor is seen only on the Golgi apparatus. more detail
We have discovered that the Golgi apparatus is the primary platform upon which RasGRP1 activates Ras in lymphocytes. We now seek to understand what are the biological advantages of endomembrane Ras signaling in immune cells and the role that Ras signaling plays in autoimmunity.