(A, B) Schematic of AKT and RSK protein domains. (C, D) Imaging the interactions between HOTAIR domains and AKT domains/RSK domains/ERK, respectively, in live cells using the iRFP-TriFC system. The nucleus was stained with Hoechst 33342. Scale bars: 10 μm. (E) The expression of the recombinant AKT D1-iRN123, AKT D2-iRN123, AKT D3-iRN123, RSK D1-iRN123, RSK D2-iRN123, and RSK D3-iRN123 in the iRFP-TriFC system was examined by Western blotting. Fig S6 is related to Fig 4.