HDAC6 functional domains. The only HDAC with two tandem catalytic domains, deacetylase domains (DD1 and DD2). Tubulin, Hsp90, and cortactin have been found to be HDAC6 substrates. The nuclear export signal (NES) prevents accumulation of the protein in the nucleus and the Ser-Glu-containing tetrapeptide (SE14) region ensures a stable anchorage of the enzyme in the cytoplasm. The linker between both DDs is able to bind dynein and the high affinity ubiquitin-binding zinc finger domain (ZnF-UBP).
