Tubacin (Tubulin acetylation inducer) is a highly potent, selective, reversible, and cell-permeable inhibitor of histone deacetylase 6 (HDAC6, IC₅₀ = 4 nM). Displays 1000-fold more selectivity for HDAC6 over other HDACs. It inhibits α-tubulin deacetylation in mammalian cells. Unlike trichostatin A (TSA), which is a broad spectrum HDAC inhibitor, tubacin is specific for the tubulin deacetylase activity of HDAC6. Tubacin causes increased acetylation of α-tubulin, accumulation of polyubiquitinated proteins, and apoptosis. It does not affect global histone deacetylation, gene-expression profiling, or cell cycle progression mediated α-tubulin deacetylation in mammalian cells.