Fig. 2: TFIP11 interacts with coilin via its disordered N-terminal region.

a HeLa cells were mock-transfected (No siRNA) or transfected with coilin siRNA (siCoilin) or control siRNA (siCtr) for 48 h. Co-staining of SMN (in red) and TFIP11 (in green) was performed. Merged channels with nuclear staining (in blue) and magnification of boxed regions are shown. Scale bar = 5 µm. b Immunoprecipitation (IP) of endogenous TFIP11 from HeLa cells followed by western blotting (WB) for the indicated proteins. c Immunoprecipitation (IP) of endogenous coilin from HeLa cells followed by western blotting (WB) for the indicated proteins. d Representative image of the interaction (in red) of endogenous TFIP11 and coilin assessed by in situ proximity ligation assay (iPLA). Nucleus was counterstained in blue. Scale bar = 5 µm. e Quantification of TFIP11/coilin interaction detected by iPLA in HeLa cells transfected with control siRNA (siCtr n = 90) or TFIP11 siRNA (siTFIP11 #1 n = 70) for 48 h. p-value calculated using unpaired two-tailed t-test (p = 0.0020). Box limits = 25th to 75th percentiles; line = median; whiskers = min to max. f Immunoprecipitation (IP) of endogenous TFIP11 from HeLa cell extracts pre-treated or not with RNAse A followed by western blotting (WB) for the indicated proteins. g Schematic representation of the TFIP11-FLAG constructs used in co-immunoprecipitation experiments. h HeLa cells were co-transfected with RFP-coilin and the TFIP11-FLAG constructs schematized in g and immunoprecipitation (IP) was performed with anti-FLAG antibodies followed by western blotting (WB) for the indicated proteins. (*) endogenous coilin. (**) exogenous RFP-coilin. i Disorder prediction along the TFIP11 sequence by three algorithms: MFDp2 (Biomine), PrDOS and DISOPRED. The threshold score for disorder is 0.5 (solid black line). j Occurrence of OPR (order-promoting residues), DPR (disorder-promoting residues) and NPR (non-promoting disorder/order residues) in the sequence of well-ordered proteins (lysozyme C, BSA), known IDPs (Osteopontin, α-Synuclein, Emerin) and TFIP11. k Charge-Hydropathy plot using the PONDR algorithm. The solid black line represents the border between ordered and disordered phases. Source data are provided as a Source Data file.