P-stalk ribosomes act as master regulators of cytokine-mediated processes

Inflammatory cytokines are pivotal to immune responses. Upon cytokine exposure, cells enter an "alert state" that enhances their visibility to the immune system. Here, we identified an alert-state subpopulation of ribosomes defined by the presence of the P-stalk. We show that P-stalk ribosomes (PSRs) are formed in response to cytokines linked to tumor immunity, and this is at least partially mediated by P-stalk phosphorylation. PSRs are involved in the preferential translation of mRNAs vital for the cytokine response via the more efficient translation of transmembrane domains of receptor molecules involved in cytokine-mediated processes. Importantly, loss of the PSR inhibits CD8+ T cell recognition and killing, and inhibitory cytokines like transforming growth factor β (TGF-β) hinder PSR formation, suggesting that the PSR is a central regulatory hub upon which multiple signals converge. Thus, the PSR is an essential mediator of the cellular rewiring that occurs following cytokine exposure via the translational regulation of this process.