In cortical neurons HDAC3 activity suppresses RD4-dependent SMRT export.

The transcriptional corepressor SMRT controls neuronal responsiveness of several transcription factors and can regulate neuroprotective and neurogenic pathways. SMRT is a multi-domain protein that complexes with HDAC3 as well as being capable of interactions with HDACs 1, 4, 5 and 7. We previously s...

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Main Authors: Francesc X Soriano, Giles E Hardingham
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2011-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0021056&type=printable
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author Francesc X Soriano
Giles E Hardingham
author_facet Francesc X Soriano
Giles E Hardingham
author_sort Francesc X Soriano
collection DOAJ
description The transcriptional corepressor SMRT controls neuronal responsiveness of several transcription factors and can regulate neuroprotective and neurogenic pathways. SMRT is a multi-domain protein that complexes with HDAC3 as well as being capable of interactions with HDACs 1, 4, 5 and 7. We previously showed that in rat cortical neurons, nuclear localisation of SMRT requires histone deacetylase activity: Inhibition of class I/II HDACs by treatment with trichostatin A (TSA) causes redistribution of SMRT to the cytoplasm, and potentiates the activation of SMRT-repressed nuclear receptors. Here we have sought to identify the HDAC(s) and region(s) of SMRT responsible for anchoring it in the nucleus under normal circumstances and for mediating nuclear export following HDAC inhibition. We show that in rat cortical neurons SMRT export can be triggered by treatment with the class I-preferring HDAC inhibitor valproate and the HDAC2/3-selective inhibitor apicidin, and by HDAC3 knockdown, implicating HDAC3 activity as being required to maintain SMRT in the nucleus. HDAC3 interaction with SMRT's deacetylation activation domain (DAD) is known to be important for activation of HDAC3 deacetylase function. Consistent with a role for HDAC3 activity in promoting SMRT nuclear localization, we found that inactivation of SMRT's DAD by deletion or point mutation triggered partial redistribution of SMRT to the cytoplasm. We also investigated whether other regions of SMRT were involved in mediating nuclear export following HDAC inhibition. TSA- and valproate-induced SMRT export was strongly impaired by deletion of its repression domain-4 (RD4). Furthermore, over-expression of a region of SMRT containing the RD4 region suppressed TSA-induced export of full-length SMRT. Collectively these data support a model whereby SMRT's RD4 region can recruit factors capable of mediating nuclear export of SMRT, but whose function and/or recruitment is suppressed by HDAC3 activity. Furthermore, they underline the fact that HDAC inhibitors can cause reorganization and redistribution of corepressor complexes.
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spelling doaj-art-85d06b8d7db549799a2b5a1f01c6121f2025-08-20T03:25:12ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-0166e2105610.1371/journal.pone.0021056In cortical neurons HDAC3 activity suppresses RD4-dependent SMRT export.Francesc X SorianoGiles E HardinghamThe transcriptional corepressor SMRT controls neuronal responsiveness of several transcription factors and can regulate neuroprotective and neurogenic pathways. SMRT is a multi-domain protein that complexes with HDAC3 as well as being capable of interactions with HDACs 1, 4, 5 and 7. We previously showed that in rat cortical neurons, nuclear localisation of SMRT requires histone deacetylase activity: Inhibition of class I/II HDACs by treatment with trichostatin A (TSA) causes redistribution of SMRT to the cytoplasm, and potentiates the activation of SMRT-repressed nuclear receptors. Here we have sought to identify the HDAC(s) and region(s) of SMRT responsible for anchoring it in the nucleus under normal circumstances and for mediating nuclear export following HDAC inhibition. We show that in rat cortical neurons SMRT export can be triggered by treatment with the class I-preferring HDAC inhibitor valproate and the HDAC2/3-selective inhibitor apicidin, and by HDAC3 knockdown, implicating HDAC3 activity as being required to maintain SMRT in the nucleus. HDAC3 interaction with SMRT's deacetylation activation domain (DAD) is known to be important for activation of HDAC3 deacetylase function. Consistent with a role for HDAC3 activity in promoting SMRT nuclear localization, we found that inactivation of SMRT's DAD by deletion or point mutation triggered partial redistribution of SMRT to the cytoplasm. We also investigated whether other regions of SMRT were involved in mediating nuclear export following HDAC inhibition. TSA- and valproate-induced SMRT export was strongly impaired by deletion of its repression domain-4 (RD4). Furthermore, over-expression of a region of SMRT containing the RD4 region suppressed TSA-induced export of full-length SMRT. Collectively these data support a model whereby SMRT's RD4 region can recruit factors capable of mediating nuclear export of SMRT, but whose function and/or recruitment is suppressed by HDAC3 activity. Furthermore, they underline the fact that HDAC inhibitors can cause reorganization and redistribution of corepressor complexes.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0021056&type=printable
spellingShingle Francesc X Soriano
Giles E Hardingham
In cortical neurons HDAC3 activity suppresses RD4-dependent SMRT export.
PLoS ONE
title In cortical neurons HDAC3 activity suppresses RD4-dependent SMRT export.
title_full In cortical neurons HDAC3 activity suppresses RD4-dependent SMRT export.
title_fullStr In cortical neurons HDAC3 activity suppresses RD4-dependent SMRT export.
title_full_unstemmed In cortical neurons HDAC3 activity suppresses RD4-dependent SMRT export.
title_short In cortical neurons HDAC3 activity suppresses RD4-dependent SMRT export.
title_sort in cortical neurons hdac3 activity suppresses rd4 dependent smrt export
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0021056&type=printable
work_keys_str_mv AT francescxsoriano incorticalneuronshdac3activitysuppressesrd4dependentsmrtexport
AT gilesehardingham incorticalneuronshdac3activitysuppressesrd4dependentsmrtexport