Assessing the role of intrinsic disorder in RNA-binding protein function: hnRNP K as a case study

RNA-binding proteins (RBPs) typically bind to RNA in a sequence-specific manner, resulting in post-transcriptional gene regulation. While the various classes of RNA-binding domains are largely structured, flexible linkers are frequently observed between them. Emerging evidence suggests that these unstructured regions may help spatially position the RNA-binding domains allowing for RNA binding and/or may contribute directly to RNA association via certain sequence motifs contained within them. The importance of these unstructured regions is widely appreciated; however, understanding their contribution to RNA binding, protein stability, and function has been difficult to ascertain. Thus, it is crucial to have a set of rapid and economical assays that do not require specialized instrumentation to study their impact on RBP function. Herein, we discuss the use of plate-based and cell-based thermal shift assays to study the impact of the intrinsically disordered region on the function of a highly conserved RBP, hnRNP K.