C, D HEK293 cells were transiently transfected with constructs expressing the indicated wild‐type or mutant GFP-USP45 [1-62] fragment (C) or GFP full‐length USP45 (D) or empty GFP (C and D) as a control and processed as described in (A). LICOR-Odyssey quantitation of results shown in (C) is shown in Supplementary Fig S4. 