IL-2-INDUCED CELLULAR EVENTS

In this review we discuss several molecules that are attractive candid ates as transducing molecules involved in signaling processes. IL-2 re ceptor signaling is a complex process involving a large number of mole cules: Ras, Rho, PI3 kinase, PKC, Akt, transcription factors NF-AT, an d NF-kappa B and some target genes such as bcl-2, c-myc, c-jun and c-S os. Ras and Rho have been defined as dual molecules because Ras-and Rh o-initiated signals can either promote or inhibit apoptosis. Several s tudies have contributed to the delineation of a signaling pathway stru ctured in three independent channels designated channels 1, 2, and 3. These three channels serve as major landmarks: Lck-c-fos/c-jun (channe l 1), Syk-myc (channel 2), and a pathway leading to actin organization /bcl-2 expression (channel 3). The detailed hierarchical organization of these three channels is presented throughout the review and the mod el is depicted in the figure.