title: CaMKII regulates proteasome phosphorylation and activity and promotes memory destabilization following retrieval.
abstract: Numerous studies have suggested that memories "destabilize" and require de novo protein synthesis in order to reconsolidate following retrieval, but very little is known about how this destabilization process is regulated. Recently, ubiquitin-proteasome mediated protein degradation has been identified as a critical regulator of memory trace destabilization following retrieval, though the specific mechanisms controlling retrieval-induced changes in ubiquitin-proteasome activity remain equivocal. Here, we found that proteasome activity is increased in the amygdala in a CaMKII-dependent manner following the retrieval of a contextual fear memory. We show that in vitro inhibition of CaMKII reversed retrieval-induced increases in proteasome activity. Additionally, in vivo pharmacological blockade of CaMKII abolished increases in proteolytic activity and activity related regulatory phosphorylation in the amygdala following retrieval, suggesting that CaMKII was "upstream" of protein degradation during the memory reconsolidation process. Consistent with this, while inhibiting CaMKII in the amygdala did not impair memory following retrieval, it completely attenuated the memory impairments that resulted from post-retrieval protein synthesis blockade. Collectively, these results suggest that CaMKII controls the initiation of the memory reconsolidation process through regulation of the proteasome.
authors.affiliation: Department of Psychology, University of Wisconsin-Milwaukee, United States.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Jarome
authors.affiliation: Department of Psychology, University of Wisconsin-Milwaukee, United States.
authors.forename: Nicole C
authors.initials: NC
authors.lastname: Ferrara
authors.affiliation: Department of Psychology, University of Wisconsin-Milwaukee, United States.
authors.forename: Janine L
authors.initials: JL
authors.lastname: Kwapis
authors.affiliation: Department of Psychology, University of Wisconsin-Milwaukee, United States. Electronic address: fjh@uwm.edu.
authors.forename: Fred J
authors.initials: FJ
authors.lastname: Helmstetter
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000679:Amygdala / Q000378:metabolism*; D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism*; D003214:Conditioning, Classical; D005239:Fear / Q000502:physiology*; D008297:Male; D000069077:Memory Consolidation / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology*; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D020318:Rats, Long-Evans
chemical_list: C491454:Psmc5 protein, rat; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D046988:Proteasome Endopeptidase Complex; D000074183:ATPases Associated with Diverse Cellular Activities
keywords: Amygdala; CaMKII; Proteasome; Reconsolidation; Ubiquitin