GAMMA-CHAIN-ASSOCIATED CYTOKINE RECEPTORS SIGNAL THROUGH DISTINCT TRANSDUCING FACTORS

The IL-2, IL-4, and IL-7 signaling pathways have been shown to utilize shared components. The receptors for these cytokines are composed of ligand-specific binding chains that associate with a shared signaling subunit, the common gamma (gamma(c)) chain. In addition, IL-2, IL-4, a nd IL-7 induce activation of a common set of nonreceptor tyrosine kina ses, Jak-1 and Jak-3. We have further investigated the signaling event s induced by these cytokines and find that the gamma(c)-associated rec eptors activate distinct signal transducing factors (STFs). In additio n, we show that a 94-kDa STAT-related protein (p94) is activated in re sponse to IL-2 and IL-7, but not IL-4. These data indicate that IL-2, IL-4, and IL-7 activate distinct signaling molecules which might be di fferentially recruited to the receptor complex by the ligand-specific units of the IL-2, IL-4, and IL-7 receptors.