IMP1 KH1 and KH2 domains create a structural platform with unique RNA recognition and re-modelling properties
journal contributionposted on 2019-12-12, 17:34 authored by Robert Dagil, Neil J Ball, Roksana W Ogrodowicz, Fruzsina Hobor, Andrew G Purkiss, Geoff Kelly, Stephen R Martin, Ian A Taylor, Andres Ramos
IGF2 mRNA-binding protein 1 (IMP1) is a key regulator of messenger RNA (mRNA) metabolism and transport in organismal development and, in cancer, its mis-regulation is an important component of tumour metastasis. IMP1 function relies on the recognition of a diverse set of mRNA targets that is mediated by the combinatorial action of multiple RNA-binding domains. Here, we dissect the structure and RNA-binding properties of two key RNA-binding domains of IMP1, KH1 and KH2, and we build a kinetic model for the recognition of RNA targets. Our data and model explain how the two domains are organized as an intermolecular pseudo-dimer and that the important role they play in mRNA target recognition is underpinned by the high RNA-binding affinity and fast kinetics of this KH1KH2-RNA recognition unit. Importantly, the high-affinity RNA-binding by KH1KH2 is achieved by an inter-domain coupling 50-fold stronger than that existing in a second pseudo-dimer in the protein, KH3KH4. The presence of this strong coupling supports a role of RNA re-modelling in IMP1 recognition of known cancer targets.
Amino Acid SequenceBinding SitesCloning, MolecularCrystallography, X-RayEscherichia coliGene ExpressionGenetic VectorsHumansKineticsModels, MolecularProtein BindingProtein Conformation, alpha-HelicalProtein Conformation, beta-StrandProtein Interaction Domains and MotifsProto-Oncogene Proteins c-mycRNA, MessengerRNA-Binding ProteinsRecombinant ProteinsSequence AlignmentSequence Homology, Amino AcidTaylor, I FC001178Frenkiel FC001029NMRSBDevelopmental Biology05 Environmental Sciences06 Biological Sciences08 Information and Computing Sciences