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Human RNA‐binding motif 3 protein (RBM3) is a cold‐shock protein which functions in various aspects of global protein synthesis, cell proliferation and apoptosis by interacting with the components of basal translational machinery. RBM3 plays important roles in tumour progression and cancer metastasis, and also has been shown to be involved in neuroprotection and endoplasmic reticulum stress response. Here, we have solved the solution NMR structure of the N‐terminal 84 residue RNA recognition motif (RRM) of RBM3. The remaining residues are rich in RGG and YGG motifs and are disordered. The RRM domain adopts a βαββαβ topology, which is found in many RNA‐binding proteins. NMR‐monitored titration experiments and molecular dynamic simulations show that the beta‐sheet and two loops form the RNA‐binding interface. Hydrogen bond, pi–pi and pi–cation are the key interactions between the RNA and the RRM domain. NMR, size exclusion chromatography and chemical cross‐linking experiments show that RBM3 forms oligomers in solution, which is favoured by decrease in temperature, thus, potentially linking it to its function as a cold‐shock protein. Temperature‐dependent NMR studies revealed that oligomerization of the RRM domain occurs via nonspecific interactions. Overall, this study provides the detailed structural analysis of RRM domain of RBM3, its interaction with RNA and the molecular basis of its temperature‐dependent oligomerization. [ABSTRACT FROM AUTHOR]

Cell adhesion molecules such as nectins and cadherins play important role in the formation of adherens junction. While nectins interact through their extracellular domains in both homophilic and heterophilic manner among themselves, extracellular domains of cadherins participate only in homophilic fashion to mediate cell‐cell adhesion. It is well established that nectins recruit cadherins in the adhesion sites through an interplay of adaptor molecules in the cytoplasmic side thereby increasing the effective concentration of both the adhesion molecules on the cell surface. This study provides molecular and structural bases of the novel interaction between extracellular domains of nectin‐2 and N‐cadherin, by which nectins can also recruit cadherins at the site of adherens junction through an adaptor‐independent mechanism. Surface plasmon resonance study demonstrates that nectin‐2 can directly recognize N‐cadherin with a KD of 3.5 ± 0.6 μM which is physiologically relevant considering the affinities between other cell adhesion molecules including cadherin dimerization. Furthermore, structural analysis of currently available homodimeric structures of both nectin‐2 and N‐cadherin followed by molecular docking as well as complementary mutagenesis studies revealed the binding interface of this novel interaction. [ABSTRACT FROM AUTHOR]