Phosphoserine-containing 14-3-3 binding motif (pS-632) in human Histone deacetylase 4 that mediates interaction with 14-3-3 protein beta and results in the sequestration of HDAC4 in the cytoplasm, wheras loss of this interaction allows HDAC4 to translocate to the nucleus, interact with HDAC3, and repress gene expression