| Furthermore , eIF 6 interacts in the cytoplasm with RACK 1 , a receptor for activated protein kinase C ( PKC ) . ^^^ Loading 60S subunits with eIF 6 caused a dose dependent translational block and impairment of 80S formation , which were reversed by expression of RACK 1 and stimulation of PKC in vivo and in vitro . ^^^ We propose that eIF 6 release regulates subunit joining , and that RACK 1 provides a physical and functional link between PKC signalling and ribosome activation . . ^^^ |