The RNA-Binding and RNA-Melting Activities of the Multifunctional Protein Nucleobindin 1

Nucleobindin 1 (NUCB1) is a ubiquitous multidomain protein that belongs to the EF-hand Ca²⁺-binding superfamily. NUCB1 interacts with Galpha_i3 protein, cyclooxygenase, amyloid precursor protein, and lipids. It is involved in stress response and human diseases. In addition, this protein is a transcription factor that binds to the DNA E-box motif. Using surface plasmon resonance and molecular beacon approaches, we first showed the RNA binding and RNA melting activities of NUCB1. We suggest that NUCB1 could induce local changes in structured RNAs via binding to the GGAUAU loop sequence. Our results demonstrate the importance of the multidomain structure of NUCB1 for its RNA-chaperone activity in vitro.