Quantitative Proteomics\nIdentifies Profilin‑1\nas a Pseudouridine-Binding Protein

Pseudouridine (Ψ) is the most abundant RNA modification\nin\nnature; however, not much is known about the biological functions\nof this modified nucleoside. Employing an unbiased quantitative proteomics\nmethod, we identified multiple candidate reader proteins of Ψ\nin RNA, including a cytoskeletal protein profilin-1 (PFN1). We demonstrated\nthat PFN1 binds directly and selectively to Ψ-containing RNA.\nAdditionally, we discovered approximately 4000 binding sites of PFN1\nin human cells, including a known dyskerin (DKC1)-installed Ψ\nsite in <i>TPI1</i> mRNA, which encodes triosephosphate\nisomerase. Moreover, we showed that PFN1 and DKC1 are crucial for\nregulating the stability and translation efficiency of <i>TPI1</i> mRNA through modulating PFN1-Ψ interaction. Together, we identified\nPFN1 as a reader protein of Ψ in RNA and illustrated a potential\nrole of PFN1-Ψ interaction in post-transcriptional regulation.\nThese findings provide new insights into the functions of Ψ\nin RNA biology and in modulating the expression of an important metabolic\nenzyme.