A combined NMR and EPR investigation on the effect of the disordered RGG regions in the structure and the activity of the RRM domain of FUS
Alessio Bonucci, Maria Grazia Murrali, Lucia Banci, Roberta Pierattelli
Abstract
Structural disorder represents a key feature in the mechanism of action of RNA-binding proteins (RBPs). Recent insights revealed that intrinsically disordered regions (IDRs) linking globular domains modulate their capability to interact with various sequences of RNA, but also regulate aggregation processes, stress-granules formation, and binding to other proteins. The FET protein family, which includes FUS (Fused in Sarcoma), EWG (Ewing Sarcoma) and TAF15 (TATA binding association factor 15) proteins, is a group of RBPs containing three different long IDRs characterized by the presence of RGG motifs. In this study, we present the characterization of a fragment of FUS comprising two RGG regions flanking the RNA Recognition Motif (RRM) alone and in the presence of a stem-loop RNA. From a combination of EPR and NMR spectroscopies, we established that the two RGG regions transiently interact with the RRM itself. These interactions may play a role in the recognition of stem-loop RNA, without a disorder-to-order transition but retaining high dynamics.