Nanocores are relatively immobile within SGs and contain multiple binding sites. (A and B) Top view (left) and kymographic representation (right) of a typical single binding event of Halo-IMP1 on SNAP-G3BP1 background (A) and Halo-G3BP1 on SNAP-IMP1 background (B) demonstrating spatial restriction of nanocores within SGs. (C) Bar plots showing the jump distance distributions of G3BP1 and IMP1 in different combinations indicating the presence of multiple binding sites within a nanocore. 14–27 transition events for each protein per condition were analyzed and the jump distance distributions determined by calculating the pairwise distances of all linked cluster centers. The box represents 50% of the population, whiskers range from 5% to 95%, and the horizontal line shows the median value.