Paper Title
CDK5 NUCLEOCYTOPLASMIC MIS LOCALIZATION UNDERLIES SEX DIFFERENCES IN STRESS RESPONSIVITY

Abstract
Cyclin-dependent kinase 5 (Cdk5) is a neuronal kinase critical for development and functioning of thenervous system, including cognition and stress responsivity. Using epigenetic editing, our lab has previously found a sexually dimorphic role for Cdk5 activation where fear memory loss and Tau hyperphosphorylation are observed only in the female mice brain.In addition, brain phosphoproteomic profiling under stress exposure shows a female-specific phosphorylation of Cdk5 protein at Threonine-17 (Thr17).Interestingly, Thr17 is crucial for Cdk5’s nuclear localization and, thus, necessary for Cdk5’s role in cell cycle suppression. Here, we test the hypothesis that Cdk5 Thr17 phosphorylation in female mice alters its nucleocytoplasmic localization. To gauge the scope of this effect, we used restriction cloning to assemble Cdk5 N-terminal truncated mutants lacking the first 17 amino acids and transfected them into primary cortical neurons. The samples were then subjected to protein compartmentalization and western blot analysis to quantify the nucleocytoplasmic protein levels. In this context, we find compartment-specific effects on Cdk5 expression. Next, we will generate phosphomimetic mutations to mimic constitutively phosphorylated Cdk5 at Thr17. These findings suggest a mechanism for Cdk5-mediated sex differences implicated in stress response pathways.