Zorc, StephenMunoz-Tello, PaolaO’Leary, TimothyYu, XiaoyuGiridhar, Mithun Nag KaradiHansel-Harris, AltheaForli, StefanoGriffin, Patrick R.Kojetin, Douglas J.Roy, Raktim N.Janiszewska, Michalina2024-06-122024-06-122024-02-17Zorc S, Munoz-Tello P, O'Leary T, et al. Structural insights into IMP2 dimerization and RNA binding. Preprint. bioRxiv. 2024;2024.02.16.580656. Published 2024 Feb 17. doi:10.1101/2024.02.16.580656https://hdl.handle.net/1805/41495IGF2BP2 (IMP2) is an RNA-binding protein that contributes to cancer tumorigenesis and metabolic disorders. Structural studies focused on individual IMP2 domains have provided important mechanistic insights into IMP2 function; however, structural information on full-length IMP2 is lacking but necessary to understand how to target IMP2 activity in drug discovery. In this study, we investigated the behavior of full-length IMP2 and the influence of RNA binding using biophysical and structural methods including mass photometry, hydrogen-deuterium exchange coupled to mass spectrometry (HDX-MS), and small angle x-ray scattering (SAXS). We found that full-length IMP2 forms multiple oligomeric states but predominantly adopts a dimeric conformation. Molecular models derived from SAXS data suggest the dimer is formed in a head-to-tail orientation by the KH34 and RRM1 domains. Upon RNA binding, IMP2 forms a pseudo-symmetric dimer different from its apo/RNA-free state, with the KH12 domains of each IMP2 molecule forming the dimer interface. We also found that the formation of IMP2 oligomeric species, which includes dimers and higher-order oligomers, is sensitive to ionic strength and RNA binding. Our findings provide the first insight into the structural properties of full-length IMP2, which may lead to novel opportunities for disrupting its function with more effective IMP2 inhibitors.en-USAttribution-NonCommercial-NoDerivatives 4.0 InternationalHDX-MSIGF2BP2IMP2RNA binding protein (RBP)SAXSArticle