Fig. 2

MEX3A undergoes IDRs-dependent LLPS and physically interacts with PBs components. a Domain structure and the intrinsically disordered regions (IDRs) of MEX3A. The IUPred score greater than 0.5 indicates disordered, as determined by the online IUPred2A algorithm (http://iupred2a.elte.hu). b The schematic diagram representing the MEX3A full-length and IDRs truncated mutant plasmids. c Representative images of turbidity associated with droplet formation. Tubes contain either only buffer (−) or recombination proteins (+) at the indicated temperature. d Representative phase-contrast microscopy images of MEX3A-FL and MEX3A-IDRs droplets formed in buffers containing 150 mM NaCl and different concentrations of protein (left) or 100 μM protein and different concentrations of NaCl (right). Scale bar, 50 μm. e Immunofluorescence (IF) assay showing EGFP-MEX3A-FL, EGFP-MEX3A-IDRs, EGFP-MEX3A-IDRs△(green) formed cytoplasmic puncta in DLD-1 cells. Nuclei were stained with DAPI (blue). Scale bar, 10 μm. f Fluorescence recovery after photobleaching (FRAP) assay of the droplets formed by EGFP-MEX3A-FL and EGFP-MEX3A-IDRs in DLD-1 cells. Top, representative images. Scale bar, 500 nm. Bottom, quantification of fluorescence intensity recovery after photobleaching. g Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showing the proteins interacting with MEX3A involved in the RNA catabolic process, RNA nonsense-mediated decay, and translation. The size of the dot indicates the number of genes per pathway. h Western blotting of MEX3A-IP assay showing the binding between MEX3A and the PBs proteins in 293 T (left) and DLD-1 cells (right). i IF assay showing that MEX3A was colocalized with the PBs proteins MOV10, PABP1, and UPF1 in DLD-1 cells. Nuclei were stained with DAPI (blue). Scale bar, 10 μm