Fig. 1: Engineering intrabodies to enable their optogenetic control.

a Schematic representation of light-induced recruitment of QPAS1-mCherry to the target protein bound to membrane, where interaction with membrane-bound mVenus occurs via intrabody (iB) fused to BphP1. b Relocalization of QPAS1-mCherry to plasma membrane under 740 nm illumination. Epifluorescence microscopy; scale bar, 10 µm. c Schematic representation of genomically expressed EGFP-PAC relocalization from cytoplasm to the cell nucleus upon illumination. d EGFP-PAC relocalization in cells expressing BphP1-iB(GFP) and NES-mCherry-QPAS1-NLS. In darkness, the QPAS1 fusion is shuttling between nucleus and cytoplasm, driven by strong NLS and weak NES. Upon 740 nm illumination, it interacts with BphP1 and recruits EGFP-PAC into the nucleus. Epifluorescence microscopy; scale bar, 10 µm. e Schematic representation of nucleus-to-cytoplasm relocalization of genomically expressed GFP-fusion using NIR light-controlled intrabody. f Cells expressing genomically EGFP-PAC and transiently BphP1-NES and iB(GFP)-NES-mCherry-QPAS1-NLS. Under 740 nm illumination, EGFP-PAC accumulates in the cytoplasm. Epifluorescence microscopy; scale bar, 10 μm. Fluorescence intensity profiles corresponding the dashed lines in b, d, and f are shown in Supplementary Fig. 1.