Hollmann, N.M., Jagtap, P.K.A., Masiewicz, P., Guitart, T., Simon, B., Provaznik, J., Stein, F., Haberkant, P., Sweetapple, L.J., Villacorta, L., Mooijman, D., Benes, V., Savitski, M.M., Gebauer, F., Hennig, J. (2020). Pseudo-RNA-Binding Domains Mediate RNA Structure Specificity in Upstream of N-Ras.  Cell Rep. 32(3): 107930.

FBrf0248824

Research paper

RNA-binding proteins (RBPs) commonly feature multiple RNA-binding domains (RBDs), which provide these proteins with a modular architecture. Accumulating evidence supports that RBP architectural modularity and adaptability define the specificity of their interactions with RNA. However, how multiple RBDs recognize their cognate single-stranded RNA (ssRNA) sequences in concert remains poorly understood. Here, we use Upstream of N-Ras (Unr) as a model system to address this question. Although reported to contain five ssRNA-binding cold-shock domains (CSDs), we demonstrate that Unr includes an additional four CSDs that do not bind RNA (pseudo-RBDs) but are involved in mediating RNA tertiary structure specificity by reducing the conformational heterogeneity of Unr. Disrupting the interactions between canonical and non-canonical CSDs impacts RNA binding, Unr-mediated translation regulation, and the Unr-dependent RNA interactome. Taken together, our studies reveal a new paradigm in protein-RNA recognition, where interactions between RBDs and pseudo-RBDs select RNA tertiary structures, influence RNP assembly, and define target specificity.

PMC7383231 (PMC) (EuropePMC)