The structure and function of YTHDF epitranscriptomic m6A readers

Specific RNA sequences modified by a methylated adenosine, N6-methyladenosine (m6A), contribute to the post-transcriptional regulation of gene expression. The quantity of m6A in RNA is orchestrated by enzymes that write and erase it, while its effects are mediated by proteins that bind to read this modification. Dysfunction of this post-transcriptional regulatory process has been linked to human disease. Although the initial focus has been on pharmacological targeting of the writer and eraser enzymes, interest in the reader proteins has been challenged by a lack of clear understanding of their functional roles and molecular mechanisms of action. Readers of m6A-modified RNA (m6A-RNA) – the YTH (YT521-B homology) domain-containing protein family paralogs 1–3 (YTHDF1–3, referred to here as DF1–DF3) – are emerging as therapeutic targets as their links to pathological processes such as cancer and inflammation and their roles in regulating m6A-RNA fate become clear. We provide an updated understanding of the modes of action of DF1–DF3 and review their structures to unlock insights into drug design approaches for DF paralog-selective inhibition.