Interaction between NVL2UD and nucleolin. A, summary of the binding assays between NVL2UD and various nucleolin fragments. B, in vitro binding assay with nucleolin fragments. Either GST (G) or GST-NVL2UD(1–74) (74) was incubated with E. coli cell lysates expressing various nucleolin fragments (in). The bound proteins were pulled down and separated using 15% SDS-PAGE. The gel was stained with Coomassie Brilliant Blue. Asterisks denote the nucleolin fragments bound to NVL2UD(1–74). C, quantification of the nucleolin fragments bound to GST-NVL2UD(1–74). The signals corresponding to the nucleolin fragments in B were integrated and normalized by their molecular weights, using ImageJ. D, RNA is involved in the NVL2-nucleolin complex. An in vitro binding assay was conducted with nucleolin (R1234G) and wild-type or mutant NVL2UD(1–74) in the presence or absence of RNase A.