Histone deacetylase inhibitor (HDACi) upregulates activin A and activates the Smad signaling pathway in melanomas

Protein function is affected by post-translational modifications, including phosphorylation, methylation and acetylation [1]. Levels of protein acetylation are controlled by two enzymes: histone acetyltransferase (HAT) and histone deacetylase (HDAC) [2]. Although HAT is involved primarily in histone acetylation, it also acetylates non-histone proteins, including p53, STAT3 and microtubules [3–5]. Acetylation status, in turn, affects gene transcription.