HDAC1 and post-traumatic stress disorder: SUMOylation of proteins such as cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), ETS Like-1 protein (Elk-1), p53 protein, and histone deacetylase 1 (HDAC1) is crucial for cognitive and emotional processes in PTSD.