Fig. 5.

CP61 disrupts CtBP dimerization in cells. (a) Subcellular localization of YFP–CtBP2 in COS-7 transfected with a plasmid encoding YFP–CtBP2. (b) Subcellular localization of CFP–CtBP1 in COS-7 transfected with a plasmid encoding CFP–CtBP1. (c) Subcellular localization of YFP–CtBP2 and CFP–CtBP1 in COS-7 cells transfected with plasmids encoding both proteins. (d and e) Cells transfected as in (c) were pre-treated with 100 μM TAT (d) or 100 μM CP61–TAT (e) to assess the effect of the peptides on inhibiting the CFP–CtBP2-dependent relocalisation of YFP–CtBP1 out of the cytoplasm and into nucleus. Right hand images shows rainbow lookup table applied to CFP image (middle panel) to demonstrate fluorescence intensity. (f and g) Line analysis (along red line) of the YFP and rainbow lookup images in (d) and (e) respectively. Overlapping peaks demonstrate co-localization in the nucleus. Arrows in (e) and (g) show cytoplasmic CFP–CtBP1 due to CP61–TAT-induced loss of its colocalization with YFP–CtBP2 in the nucleus. (h) Results of line analysis of cells treated with 100 μM TAT or 100 μM CP61–TAT, scored for presence of cytoplasmic CFP–CtBP1. Number of cells analyzed in brackets. * = statistical difference from TAT-treated cells (P = 0.0011 Fishers exact contingency table).