Table 1. Comparison of Available Cellular Target Engagement Methods for the Tubulin Deacetylases Sirt2 and HDAC6.

	method
	α-tubulin acetylation	CETSA	PROTAC	NanoBRET
principle	activity-based	thermal stability	proximity-based	proximity-based
secondary detection method	Western blot, fluorescence microscopy	Western blot	Western blot	not required
modified ligand (tracer)	not required	not required	required	required
modified protein	not required	not required	not required	required
assay protocol	heterogeneous	heterogeneous	heterogeneous	homogeneous