Rhes efficiently transports mHTT between striatal neuronal cells, and in primary striatal neurons via TNT-like Rhes tunnels. (A) Experimental design for B and C. (B) FACS plot and co-culture of striatal cells transfected with Rhes and HTT constructs as indicated. BFP cell population was gated and a total 20,000 cells recorded. (C–E) Bar graphs show data mean ± SEM; one-way ANOVA test (***, P < 0.001), n = 3. Quantification of BFP cells (%) positive for both GFP and mCherry fluorescence (C), only mCherry (D), or only GFP fluorescence (E). (F) Representative confocal and DIC images of primary striatal neurons cotransfected with GFP-Rhes and mCherry mHTT. Arrows (white) indicate TNT-like process from cell 1 connecting cell 2. Arrowheads indicate GFP-Rhes and mHTT vesicular puncta in neighboring cell 3. Red arrows indicate the colocalization of Rhes and mHTT puncta in cell 2.