Although the mechanisms of generation of signals that control transcriptional activation of
Type III IFN (IFNλ)-regulated genes have been identified, very little is known about the
mechanisms by which the IFNλ receptor generates signals for mRNA translation of IFNλ-
activated genes. We provide evidence that IFNλ activates the p90 ribosomal protein S6
kinase 1 (RSK1) and its downstream effector, initiation factor eIF4B. Prior to its engagement
by the IFNλ receptor, the non-active form of RSK1 is present in a complex with the …