Figure 3: Multiple surfaces of FBXL17 contribute to substrate binding.

a. Detailed view of the interface between FBXL17 (orange) and the BTB domain of KEAP1^F64A (blue). b. Combined mutation of FBXL17 residues in LRRs and CTH prevents recognition of ^HAKEAP1, as shown by FBXL17^FLAG affinity-purification and quantitative αHA-LiCor Western blotting. c. Combined mutations in FBXL17 interfere with proteasomal degradation of KEAP1, as monitored by quantitative Western blotting. d. Mutations in FBXL17 prevent recognition of endogenous BTB proteins, as determined by affinity-purification and mass spectrometry. The heat map shows total spectral counts normalized to FBXL17. e. Mutation of residues in ^HAKEAP1 inhibits binding to SCF^FBXL17, as seen upon FBXL17^FLAG affinity-purification and quantitative αHA-Western blotting. f. Combined mutations in KEAP1 inhibit SCF^FBXL17-dependent degradation, as monitored by quantitative Western blotting.