Purification of RNF43 interactors was performed with the following 4 different constructs: (i) empty vector (EV) as a control for background contaminants/non-specific protein binding; (ii) full-length RNF43 protein (RNF43 FL); (iii) deleted version of RNF43 harboring only the PA-TA domain (RNF43 Δ1); and (iv) deleted version of RNF43 harboring only the PA-TA-RING domain (RNF43 Δ3). HEK293T cells were transfected with pcDNA3-FLAG-HA- RNF43 (FL, Δ1 or Δ3).