Neurogranin Regulates Metaplasticity

Long-term potentiation (LTP) and long-term depression (LTD) are two major forms of synaptic plasticity that are widely accepted as cellular mechanisms involved in learning and memory. Metaplasticity is a process whereby modifications in synaptic processes shift the threshold for subsequent plasticit...

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Main Authors: Ling Zhong, Nashaat Z. Gerges
Format: Article
Language:English
Published: Frontiers Media S.A. 2020-01-01
Series:Frontiers in Molecular Neuroscience
Subjects:
Online Access:https://www.frontiersin.org/article/10.3389/fnmol.2019.00322/full
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author Ling Zhong
Nashaat Z. Gerges
author_facet Ling Zhong
Nashaat Z. Gerges
author_sort Ling Zhong
collection DOAJ
description Long-term potentiation (LTP) and long-term depression (LTD) are two major forms of synaptic plasticity that are widely accepted as cellular mechanisms involved in learning and memory. Metaplasticity is a process whereby modifications in synaptic processes shift the threshold for subsequent plasticity. While metaplasticity has been functionally observed, its molecular basis is not well understood. Here, we report that neurogranin (Ng) regulates metaplasticity by shifting the threshold toward potentiation, i.e., increasing Ng in hippocampal neurons lowers the threshold for LTP and augments the threshold for LTD. We also show that Ng does not change the ultrastructural localization of calmodulin (CaM)-dependent protein Kinase II (CaMKII) or calcineurin, critical enzymes for the induction of LTP and LTD, respectively. Interestingly, while CaMKII concentrates close to the plasma membrane, calcineurin concentrates away from the plasma membrane. These data, along with the previous observation showing Ng targets CaM closer to the plasma membrane, suggesting that shifting the localization of CaM within the dendritic spines and closer to the plasma membrane, where there is more CaMKII, may be favoring the activation of CaMKII vs. that of calcineurin. Thus, the regulation of CaM localization/targeting within dendritic spines by Ng may provide a mechanistic basis for the regulation of metaplasticity.
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spelling doaj.art-0927477260a84b2bac7c0ceba35329922022-12-22T01:28:24ZengFrontiers Media S.A.Frontiers in Molecular Neuroscience1662-50992020-01-011210.3389/fnmol.2019.00322497217Neurogranin Regulates MetaplasticityLing ZhongNashaat Z. GergesLong-term potentiation (LTP) and long-term depression (LTD) are two major forms of synaptic plasticity that are widely accepted as cellular mechanisms involved in learning and memory. Metaplasticity is a process whereby modifications in synaptic processes shift the threshold for subsequent plasticity. While metaplasticity has been functionally observed, its molecular basis is not well understood. Here, we report that neurogranin (Ng) regulates metaplasticity by shifting the threshold toward potentiation, i.e., increasing Ng in hippocampal neurons lowers the threshold for LTP and augments the threshold for LTD. We also show that Ng does not change the ultrastructural localization of calmodulin (CaM)-dependent protein Kinase II (CaMKII) or calcineurin, critical enzymes for the induction of LTP and LTD, respectively. Interestingly, while CaMKII concentrates close to the plasma membrane, calcineurin concentrates away from the plasma membrane. These data, along with the previous observation showing Ng targets CaM closer to the plasma membrane, suggesting that shifting the localization of CaM within the dendritic spines and closer to the plasma membrane, where there is more CaMKII, may be favoring the activation of CaMKII vs. that of calcineurin. Thus, the regulation of CaM localization/targeting within dendritic spines by Ng may provide a mechanistic basis for the regulation of metaplasticity.https://www.frontiersin.org/article/10.3389/fnmol.2019.00322/fullLTPLTDsynaptic plasticitycalmodulinneurograninCaMKII
spellingShingle Ling Zhong
Nashaat Z. Gerges
Neurogranin Regulates Metaplasticity
Frontiers in Molecular Neuroscience
LTP
LTD
synaptic plasticity
calmodulin
neurogranin
CaMKII
title Neurogranin Regulates Metaplasticity
title_full Neurogranin Regulates Metaplasticity
title_fullStr Neurogranin Regulates Metaplasticity
title_full_unstemmed Neurogranin Regulates Metaplasticity
title_short Neurogranin Regulates Metaplasticity
title_sort neurogranin regulates metaplasticity
topic LTP
LTD
synaptic plasticity
calmodulin
neurogranin
CaMKII
url https://www.frontiersin.org/article/10.3389/fnmol.2019.00322/full
work_keys_str_mv AT lingzhong neurograninregulatesmetaplasticity
AT nashaatzgerges neurograninregulatesmetaplasticity