Cover photograph (Copyright © 2000, American Society for Microbiology. All rights reserved.): Shc signals to the phophatidylinositol 3-kinase (PI-3K)/Akt pathway via a Grb2-Gab2 complex in cytokine receptor signaling, although Shc is known to promote Ras activation by recruiting the Grb2-Sos complex. Shown are routes from the interleukin-3 (IL-3)/granulocyte-macrophage colony-stimulating factor/IL-5 receptors, which utilize the  common chain (c), and the IL-2/IL-15 receptors, which signal via IL-2R. For c, tyrosyl-phosphorylated Shc provides the major route to the activation of the PI-3K/Akt pathway via the Grb2-Gab2 complex; tyrosyl-phosphorylated Shp-2 may provide an alternate route. In IL-2R signaling, Shc provides the only route to PI-3K/Akt via the Grb2-Gab2 complex. (See related article in October 2000, issue 19: vol. 20, p. 7109.)