A hippocampal Cdk5 pathway regulates extinction of contextual fear

Farahnaz Sananbenesi, Andre Fischer, Xinyu Wang, Christina Schrick, Rachael Neve, Jelena Radulovic, Li Huei Tsai

Research output: Contribution to journalArticlepeer-review

123 Scopus citations


Treatment of emotional disorders involves the promotion of extinction processes, which are defined as the learned reduction of fear. The molecular mechanisms underlying extinction have only begun to be elucidated. By employing genetic and pharmacological approaches in mice, we show here that extinction requires downregulation of Rac-1 and cyclin-dependent kinase 5 (Cdk5), and upregulation of p21 activated kinase-1 (PAK-1) activity. This is physiologically achieved by a Rac-1-dependent relocation of the Cdk5 activator p35 from the membrane to the cytosol and dissociation of p35 from PAK-1. Moreover, our data suggest that Cdk5/p35 activity prevents extinction in part by inhibition of PAK-1 activity in a Rac-1-dependent manner. We propose that extinction of contextual fear is regulated by counteracting components of a molecular pathway involving Rac-1, Cdk5 and PAK-1. Our data suggest that this pathway could provide a suitable target for therapeutic treatment of emotional disorders.

Original languageEnglish (US)
Pages (from-to)1012-1019
Number of pages8
JournalNature Neuroscience
Issue number8
StatePublished - Aug 2007
Externally publishedYes

ASJC Scopus subject areas

  • Neuroscience(all)


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