As such, these proteins may represent critical intrinsic mechanisms for counteracting the maladaptive changes in reward circuit function, and understanding these negative feedback processes may reveal new avenues Cyclopamine order for the treatment of drug addiction. Taken together, our findings reveal that cocaine regulates the transient

nuclear accumulation of HDAC5, and this likely occurs through a molecular mechanism involving PP2A phosphatase-dependent dephosphorylation of HDAC5 at three critical phosphoserines: S259, S279, and S498. The removal of phosphate from these sites likely increases the NLS function and decreases binding to 14-3-3 proteins, and promotes the repression of HDAC5 target genes in the nucleus. Importantly, our findings reveal that dephosphorylation of S279 HDAC5 is critical for its ability to limit the development of cocaine reward-related behavioral adaptations, but not natural reward behavior. Because cocaine-experienced HDAC5 KO mice have enhanced place preference

to cocaine, and this effect is rescued by NAc expression of WT HDAC5 (Renthal et al., 2007), our combined findings suggest that HDAC5 provides a delayed braking mechanism on gene expression selleckchem programs that support the development, but not expression, of cocaine reward behaviors. As such, deficits in this process may contribute to the development of maladaptive behaviors Phosphoprotein phosphatase associated with addiction following repeated drug use in humans. Herpes simplex virus (HSV)-flag-human HDAC5 plasmid was provided by Dr. Eric Nestler, and using PCR, we generated a nontagged version

of HDAC5 for subcloning. The PCR fragment was subcloned into Bluescript vector, and the insert region was confirmed by DNA sequencing. The nontagged HDAC5 was then digested with XbaI and subcloned into HSV vector. Serine to alanine (S259A, S279A, S498A) and serine to glutamate (S279E) mutants of HDAC5 were generated by QuickChange Site-Directed Mutagenesis Kit. All C57BL/6 mice (Charles River) used in this study were adult males tested between 10 and 12 weeks old. They were housed on a 12 hr light-dark cycle with access to food and water ad libitum. All procedures were in accordance with the Institutional Animal Care and Use (IACUC) guidelines. Rabbits were injected with a synthesized P-HDAC5 encompassing HDAC5 amino acids 274–285, where position S279 was phosphorylated (Covance). The injected peptide was conjugated to Keyhole Limpet Hemocyanin via an N-terminal cysteine residue. Anti-P-S279 antibodies were affinity purified with peptide-conjugated Sepharose beads (SulfoLink; Pierce). Embryonic striatal neurons (E18/19) were cultured from Long-Evans rats (Charles River) as described previously (Cowan et al., 2005 and Pulipparacharuvil et al., 2008). Details can be found in the Supplemental Experimental Procedures section.