Quantitative RNA interactome capture (qRIC) identifies phosphorylation sites with regulatory potential

ABSTRACT: RNA binding proteins (RBPs) are major regulators of gene expression at the post-transcriptional level. While many posttranslational modification sites in RBPs have been identified, less is known about how these modifications regulate RBP function. Here, we develop quantitative RNA-interactome capture (qRIC) to quantify the fraction of cellular RBPs pulled down with polyadenylated mRNAs. Applying qRIC to HEK293T cells quantified pulldown efficiencies of over 300 mRBPs. Combining qRIC with phosphoproteomics allowed us to systematically compare pulldown efficiencies of phosphorylated and non-phosphorylated forms of mRBPs. Over hundred phosphorylation sites show increased or decreased pull-down efficiency compared to their host RBPs and thus have regulatory potential. Our data captures known regulatory phosphorylation sites in ELAVL1, SF3B1 and UPF1 and identifies new potentially regulatory sites. Follow-up experiments on the cardiac splicing regulator RBM20 revealed that multiple phosphorylation sites in the C-terminal disordered region affect nucleo-cytoplasmic shuttling, association with cytosolic RNA granules and alternative splicing. Together, we show that qRIC is a scalable method to identify the function of posttranslational modifications in RBPs.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Permanent Cell Line Cell, Cell Culture

SUBMITTER: Carlos Henrique Vieira e Vieira  

LAB HEAD: Matthias Selbach

PROVIDER: PXD027137 | Pride | 2022-09-05

REPOSITORIES: Pride