RNA-binding proteins and ribonucleoproteins as determinants of immunity.

Infection triggers one of the most dramatic systemic responses in the body, and the coordinated activation and function of immune cells requires a dynamic regulation of transcriptomes and proteomes. This is achieved by RNA-binding proteins, which, together with RNA, form ribonucleoproteins. These proteins expand the information content of the genome and determine the lifespan, localization and function of RNA. Moreover, they control when, where and how much protein is produced. They can also mediate cell-autonomous immunity to foreign RNA and to misfolded self-RNAs and ensure the fidelity of the transcriptome by acting as RNA modifiers and chaperones to prevent RNA misfolding. These activities are integrated with gene expression programmes that are induced by the pathogen-sensing mechanisms of immune cells, which together activate, and later resolve, immune responses. Here, we review the activities of RNA-binding proteins in immune cells and discuss how perturbations of their function can result in immunodeficiency, autoimmunity and chronic inflammation.