Fig. 2: MRNIP undergoes liquid-liquid phase separation.

a FRAP of MRNIP-GFP puncta in cells. b FRAP of MRNIP-GFP puncta in ATP-depleted cells. For (a, b), data are presented as means ± SEM; n = 3 biological replicates. c Fusion of adjacent MRNIP-GFP droplets was observed in cells. d One MRNIP-GFP droplet fissured to form two smaller droplets. e, f MRNIP-GFP droplets were disrupted by 10% 1,6-hexanediol and recovered after removal of 1,6-hexanediol. For (a–f), HeLa cells were transfected with plasmid for 24 h before observation using confocal microscopy. g MRNIP solution was muddied in a temperature-independent manner, whereas the GFP solution remained clear. h MRNIP-GFP droplets that formed in buffers containing 150 mM NaCl were observed with confocal microscopy. i The impact of protein concentration and NaCl concentration on the formation of MRNIP-GFP droplets. The fluorescence intensity of droplets is presented as the area × mean intensity (A. × M.). j, k Characterization of the morphology of MRNIP droplets using AFM in tapping mode (j) or contact mode (k). l A region within the MRNIP-GFP droplets was photobleached, and fluorescence recovered rapidly. m Three in vitro-formed MRNIP-GFP droplets fused to form a larger droplet. n MRNIP-GFP droplets were disrupted by dilution and increasing NaCl concentrations. Droplets formed in buffer containing 10 μM MRNIP-GFP and 150 mM NaCl at pH 7.4 and mixed with equal volume of buffer containing 150 mM NaCl at pH 7.4; high salt, 300 mM NaCl. Data are presented as means ± SEM. n = 99 (Droplets), n = 23 (1/2 dilution), n = 40 ( + High salt). Two-tailed unpaired Student’s t test.