Interaction of “readthrough” acetylcholinesterase with RACK1 and PKCβII correlates with intensified fear-induced conflict behavior

Abstract

Behavioral reactions to stress are altered in numerous psychiatric and neurodegenerative syndromes, but the corresponding molecular processes and signal transduction pathways are yet unknown. Here, we report that, in mice, the stress-induced splice variant of acetylcholinesterase, AChE-R, interacts intraneuronally with the scaffold protein RACK1 and through it, with its target, protein kinase C␤II (PKC␤II), which is known to be involved in fear conditioning. In stress-responsive brain regions of normal FVB͞N mice, the mild stress of i.p. injection increased AChE and PKC␤II levels in a manner suppressible by antisense prevention of AChE-R accumulation. Injection stress also prolonged conflict between escape and hiding in the emergence into an open field test. Moreover, transgenic FVB͞N mice overexpressing AChE-R displayed prolonged delay to emerge into another field (fear-induced behavioral inhibition), associated with chronically intensified neuronal colabeling of RACK1 and PKC␤II in stress-responsive brain regions. These findings are consistent with the hypothesis that stressassociated changes in cholinergic gene expression regulate neuronal PKC␤II functioning, promoting fear-induced conflict behavior after stress.

Differential localization of acetylcholinesterase in neuronal and non‐neuronal cells

“…Anti-huAChE was diluted 1:1,500 in blocking buffer (5% non-fat dehydrated milk in PBS/0.3% Tween-20) and secondary anti-mouse IgG conjugated to HRP (Cell Signaling Technology, Beverly, MA) was diluted 1:1,000 in blocking buffer. Primary anti-AChE core polyclonal antibody (N19; Santa Cruz Biotechnologies, Inc., Santa Cruz, CA) has previously been used to detect AChE in immunoprecipitation and immunoblot assays [Birikh et al, 2003;Darreh-Shori et al, 2004;Meshorer et al, 2004]. N19 was diluted 1:500 in blocking buffer, and secondary anti-goat IgG conjugated to HRP (Vector Laboratories, Inc., Burlingame, CA) was diluted 1:2,000 in blocking buffer.…”

Quantitative and evolutionary biology of alternative splicing: how changing the mix of alternative transcripts affects phenotypic plasticity and reaction norms

“…AChE-R has been shown (Birikh et al, 2003) to interact in neurons with the scaffold protein RACK1, and through it with protein kinase CII, a signaling molecule involved in fear conditioning. Mice exposed to mild stress, and transgenic mice overexpressing AChE-R, show fearful behavioral traits such as delayed willingness to emerge from a box into an open field.…”

Involvement of the PRKCB1 gene in autistic disorder: significant genetic association and reduced neocortical gene expression

“…In particular, brain PRKCB1 is expressed in hippocampus, striatum, suprachiasmatic nucleus and cerebellar granule cells, where PKCbI influences circadian rhythms, learning and memory, whereas PKCbII is involved in fear conditioning. [15][16][17][18][19] In the immune system, PKCb isoenzymes play a critical role in B-cell receptor-mediated responses, T-cell migration and cytokine secretion, dendritic cell differentiation and monocyte and macrophage functioning. [20][21][22][23][24][25] In the gut, PKCbI and bII are expressed by epithelial cells, where they regulate intestinal permeability and cell proliferation, respectively.…”