Additional TurboID controls indicating that ARP3 TurboID activity is specific. (A) Representative immunoblot showing that ARP3 V5 TurboID and a cytoplasmic nonspecific TurboID are able to biotinylate endogenous COR1C. Blots show the same samples run twice to blot for either endogenous COR1C or V5. Performed in triplicate. (B) Quantification of blots in A showing the amount of COR1C signal in the elute normalized first to the relevant TurboID V5 signal in the input and then to the max value within each replicate. (C) Representative immunoblot showing that ARP3 V5 TurboID has uniquely specific biotinylation of COR1C as shown by its ability to biotinylate only COR1C-GFP and not COR1C ACT– ΔCC-GFP. In contrast, the Cyto V5 TurboID biotinylates proteins nonspecifically in the cytoplasm as shown by similar biotinylation profiles for both COR1C-GFP and COR1C ACT–-ΔCC-GFP. Performed in triplicate. (D) Quantification of blots in C, from three replicates. Graph shows the ratio of COR1C-GFP to COR1C ACT–ΔCC-GFP signal in the elution. Signals in ratio were normalized to both relevant GFP and V5 input signals and then to the minimum value in each replicate. Statistical analysis was performed via two-tailed Student’s t test; *, P < 0.05. X indicates mean, and line indicates median. Source data are available for this figure: SourceData FS3.