Genetic removal of eIF 2α kinase PERK in mice enables hippocampal L‐ LTP independent of mTORC 1 activity
Abstract Characterization of the molecular signaling pathways underlying protein synthesis‐dependent forms of synaptic plasticity, such as late long‐term potentiation (L‐ LTP ), can provide insights not only into memory expression/maintenance under physiological conditions but also potential mechani...
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Published in | Journal of neurochemistry Vol. 146; no. 2; pp. 133 - 144 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
01.07.2018
|
Online Access | Get full text |
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Summary: | Abstract
Characterization of the molecular signaling pathways underlying protein synthesis‐dependent forms of synaptic plasticity, such as late long‐term potentiation (L‐
LTP
), can provide insights not only into memory expression/maintenance under physiological conditions but also potential mechanisms associated with the pathogenesis of memory disorders. Here, we report in mice that L‐
LTP
failure induced by the mammalian (mechanistic) target of rapamycin complex 1 (
mTORC
1) inhibitor rapamycin is reversed by brain‐specific genetic deletion of
PKR
‐like
ER
kinase,
PERK
(
PERK KO
), a kinase for eukaryotic initiation factor 2α (
eIF
2α). In contrast, genetic removal of general control non‐derepressible‐2,
GCN
2 (
GCN
2
KO
), another
eIF
2α kinase, or treatment of hippocampal slices with the
PERK
inhibitor
GSK
2606414, does not rescue rapamycin‐induced L‐
LTP
failure, suggesting mechanisms independent of
eIF
2α phosphorylation. Moreover, we demonstrate that phosphorylation of eukaryotic elongation factor 2 (
eEF
2) is significantly decreased in
PERK KO
mice but unaltered in
GCN
2
KO
mice or slices treated with the
PERK
inhibitor. Reduction in
eEF
2 phosphorylation results in increased general protein synthesis, and thus could contribute to the
mTORC
1‐independent L‐
LTP
in
PERK KO
mice. We further performed experiments on mutant mice with genetic removal of
eEF
2K (
eEF
2K
KO
), the only known kinase for
eEF
2, and found that L‐
LTP
in
eEF
2K
KO
mice is insensitive to rapamycin. These data, for the first time, connect reduction in
PERK
activity with the regulation of translation elongation in enabling L‐
LTP
independent of
mTORC
1. Thus, our findings indicate previously unrecognized levels of complexity in the regulation of protein synthesis‐dependent synaptic plasticity.
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Cover Image for this issue: doi:
10.1111/jnc.14185
. |
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ISSN: | 0022-3042 1471-4159 |
DOI: | 10.1111/jnc.14306 |