Among the identified HDACs (HDAC1-4 and HDAC6-8), AP1 selectively degraded HDAC6 after 5 hours of incubation with 1 µM of AP1 (Figure ). In addition, degradation of the CRBN neosubstrates IKZF1 and ZFP1 was observed. In conclusion, MS-based whole proteome analysis, in combination with our western blot results verified that AP1 is a selective degrader of HDAC6/10.