Fig. 4

Targeted recruitment and enrichment of cargo proteins in RGG-based compartments. a Schematic of cargo recruitment into RGG-RGG liquid droplets. b Three strategies for recruitment of model cargo, RFP, that is normally excluded from RGG-RGG droplets: (i) recruitment via a single RGG domain, (ii) recruitment via two RGG domains, and (iii) recruitment via a high-affinity SYNZIP (SZ)-binding pair, in which SZ1 is attached to phase-separating RGG-RGG and its binding partner SZ2 is attached to RFP. Domain schematics and fluorescence micrographs of cargo enrichment are shown. Cargo protein concentration: 1 μM. RGG-RGG or SZ1-RGG-RGG concentration: 6 μM. c Quantification of cargo enrichment. Fluorescence intensity line scans of representative droplets show weak recruitment with a single RGG domain, vs. strong and uniform recruitment by two RGG domains or by SZ1/SZ2 binding. d Simultaneous recruitment of multiple cargo proteins, GFP-SZ2 and RFP-SZ2, into SZ1-RGG-RGG droplets. Merged image shows co-recruitment (yellow). Scale bars: 10 µm