---
_id: '14253'
abstract:
- lang: eng
text: Junctions between the endoplasmic reticulum (ER) and the plasma membrane (PM)
are specialized membrane contacts ubiquitous in eukaryotic cells. Concentration
of intracellular signaling machinery near ER-PM junctions allows these domains
to serve critical roles in lipid and Ca2+ signaling and homeostasis. Subcellular
compartmentalization of protein kinase A (PKA) signaling also regulates essential
cellular functions, however, no specific association between PKA and ER-PM junctional
domains is known. Here, we show that in brain neurons type I PKA is directed to
Kv2.1 channel-dependent ER-PM junctional domains via SPHKAP, a type I PKA-specific
anchoring protein. SPHKAP association with type I PKA regulatory subunit RI and
ER-resident VAP proteins results in the concentration of type I PKA between stacked
ER cisternae associated with ER-PM junctions. This ER-associated PKA signalosome
enables reciprocal regulation between PKA and Ca2+ signaling machinery to support
Ca2+ influx and excitation-transcription coupling. These data reveal that neuronal
ER-PM junctions support a receptor-independent form of PKA signaling driven by
membrane depolarization and intracellular Ca2+, allowing conversion of information
encoded in electrical signals into biochemical changes universally recognized
throughout the cell.
acknowledgement: We thank Kayla Templeton and Peter Turcanu for technical assistance,
Michelle Salemi for assistance with LC-MS data acquisition and analysis, Dr. Belvin
Gong for advice on monoclonal antibody generation, Drs. Maria Casas Prat and Eamonn
Dickson for assistance with super-resolution TIRF microscopy, Dr. Oscar Cerda for
assistance with the design of TAT-FFAT peptides, Dr. Fernando Santana for helpful
discussions, and Dr. Jodi Nunnari for a careful reading of our manuscript. We also
thank Dr. Alan Howe, Dr. Sohum Mehta, and Dr. Jin Zhang for providing plasmids used
in this study. This project was funded by NIH Grants R01NS114210 and R21NS101648
(J.S.T.), and F32NS108519 (N.C.V.).
article_number: '5231'
article_processing_charge: Yes
article_type: original
author:
- first_name: Nicholas C.
full_name: Vierra, Nicholas C.
last_name: Vierra
- first_name: Luisa
full_name: Ribeiro-Silva, Luisa
last_name: Ribeiro-Silva
- first_name: Michael
full_name: Kirmiz, Michael
last_name: Kirmiz
- first_name: Deborah
full_name: Van Der List, Deborah
last_name: Van Der List
- first_name: Pradeep
full_name: Bhandari, Pradeep
id: 45EDD1BC-F248-11E8-B48F-1D18A9856A87
last_name: Bhandari
orcid: 0000-0003-0863-4481
- first_name: Olivia A.
full_name: Mack, Olivia A.
last_name: Mack
- first_name: James
full_name: Carroll, James
last_name: Carroll
- first_name: Elodie
full_name: Le Monnier, Elodie
id: 3B59276A-F248-11E8-B48F-1D18A9856A87
last_name: Le Monnier
- first_name: Sue A.
full_name: Aicher, Sue A.
last_name: Aicher
- first_name: Ryuichi
full_name: Shigemoto, Ryuichi
id: 499F3ABC-F248-11E8-B48F-1D18A9856A87
last_name: Shigemoto
orcid: 0000-0001-8761-9444
- first_name: James S.
full_name: Trimmer, James S.
last_name: Trimmer
citation:
ama: Vierra NC, Ribeiro-Silva L, Kirmiz M, et al. Neuronal ER-plasma membrane junctions
couple excitation to Ca2+-activated PKA signaling. Nature Communications.
2023;14. doi:10.1038/s41467-023-40930-6
apa: Vierra, N. C., Ribeiro-Silva, L., Kirmiz, M., Van Der List, D., Bhandari, P.,
Mack, O. A., … Trimmer, J. S. (2023). Neuronal ER-plasma membrane junctions couple
excitation to Ca2+-activated PKA signaling. Nature Communications. Springer
Nature. https://doi.org/10.1038/s41467-023-40930-6
chicago: Vierra, Nicholas C., Luisa Ribeiro-Silva, Michael Kirmiz, Deborah Van Der
List, Pradeep Bhandari, Olivia A. Mack, James Carroll, et al. “Neuronal ER-Plasma
Membrane Junctions Couple Excitation to Ca2+-Activated PKA Signaling.” Nature
Communications. Springer Nature, 2023. https://doi.org/10.1038/s41467-023-40930-6.
ieee: N. C. Vierra et al., “Neuronal ER-plasma membrane junctions couple
excitation to Ca2+-activated PKA signaling,” Nature Communications, vol.
14. Springer Nature, 2023.
ista: Vierra NC, Ribeiro-Silva L, Kirmiz M, Van Der List D, Bhandari P, Mack OA,
Carroll J, Le Monnier E, Aicher SA, Shigemoto R, Trimmer JS. 2023. Neuronal ER-plasma
membrane junctions couple excitation to Ca2+-activated PKA signaling. Nature Communications.
14, 5231.
mla: Vierra, Nicholas C., et al. “Neuronal ER-Plasma Membrane Junctions Couple Excitation
to Ca2+-Activated PKA Signaling.” Nature Communications, vol. 14, 5231,
Springer Nature, 2023, doi:10.1038/s41467-023-40930-6.
short: N.C. Vierra, L. Ribeiro-Silva, M. Kirmiz, D. Van Der List, P. Bhandari, O.A.
Mack, J. Carroll, E. Le Monnier, S.A. Aicher, R. Shigemoto, J.S. Trimmer, Nature
Communications 14 (2023).
date_created: 2023-09-03T22:01:14Z
date_published: 2023-08-26T00:00:00Z
date_updated: 2023-09-06T06:53:32Z
day: '26'
ddc:
- '570'
department:
- _id: RySh
doi: 10.1038/s41467-023-40930-6
external_id:
pmid:
- '37633939'
file:
- access_level: open_access
checksum: 6ab8aab4e957f626a09a1c73db3388fb
content_type: application/pdf
creator: dernst
date_created: 2023-09-06T06:50:07Z
date_updated: 2023-09-06T06:50:07Z
file_id: '14270'
file_name: 2023_NatureComm_Vierra.pdf
file_size: 9412549
relation: main_file
success: 1
file_date_updated: 2023-09-06T06:50:07Z
has_accepted_license: '1'
intvolume: ' 14'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '08'
oa: 1
oa_version: Published Version
pmid: 1
publication: Nature Communications
publication_identifier:
eissn:
- 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Neuronal ER-plasma membrane junctions couple excitation to Ca2+-activated PKA
signaling
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 14
year: '2023'
...
---
_id: '9437'
abstract:
- lang: eng
text: The synaptic connection from medial habenula (MHb) to interpeduncular nucleus
(IPN) is critical for emotion-related behaviors and uniquely expresses R-type
Ca2+ channels (Cav2.3) and auxiliary GABAB receptor (GBR) subunits, the K+-channel
tetramerization domain-containing proteins (KCTDs). Activation of GBRs facilitates
or inhibits transmitter release from MHb terminals depending on the IPN subnucleus,
but the role of KCTDs is unknown. We therefore examined the localization and function
of Cav2.3, GBRs, and KCTDs in this pathway in mice. We show in heterologous cells
that KCTD8 and KCTD12b directly bind to Cav2.3 and that KCTD8 potentiates Cav2.3
currents in the absence of GBRs. In the rostral IPN, KCTD8, KCTD12b, and Cav2.3
co-localize at the presynaptic active zone. Genetic deletion indicated a bidirectional
modulation of Cav2.3-mediated release by these KCTDs with a compensatory increase
of KCTD8 in the active zone in KCTD12b-deficient mice. The interaction of Cav2.3
with KCTDs therefore scales synaptic strength independent of GBR activation.
acknowledgement: We are grateful to Akari Hagiwara and Toshihisa Ohtsuka for CAST
antibody, and Masahiko Watanabe for neurexin antibody. We thank David Adams for
kindly providing the stable Cav2.3 cell line. Cav2.3 KO mice were kindly provided
by Tsutomu Tanabe. This project has received funding from the European Research
Council (ERC) and European Commission (EC), under the European Union’s Horizon 2020
research and innovation programme (ERC grant agreement no. 694539 to Ryuichi Shigemoto,
no. 692692 to Peter Jonas, and the Marie Skłodowska-Curie grant agreement no. 665385
to Cihan Önal), the Swiss National Science Foundation Grant 31003A-172881 to Bernhard
Bettler and Deutsche Forschungsgemeinschaft (For 2143) and BIOSS-2 to Akos Kulik.
article_number: e68274
article_processing_charge: No
article_type: original
author:
- first_name: Pradeep
full_name: Bhandari, Pradeep
id: 45EDD1BC-F248-11E8-B48F-1D18A9856A87
last_name: Bhandari
orcid: 0000-0003-0863-4481
- first_name: David H
full_name: Vandael, David H
id: 3AE48E0A-F248-11E8-B48F-1D18A9856A87
last_name: Vandael
orcid: 0000-0001-7577-1676
- first_name: Diego
full_name: Fernández-Fernández, Diego
last_name: Fernández-Fernández
- first_name: Thorsten
full_name: Fritzius, Thorsten
last_name: Fritzius
- first_name: David
full_name: Kleindienst, David
id: 42E121A4-F248-11E8-B48F-1D18A9856A87
last_name: Kleindienst
- first_name: Hüseyin C
full_name: Önal, Hüseyin C
id: 4659D740-F248-11E8-B48F-1D18A9856A87
last_name: Önal
orcid: 0000-0002-2771-2011
- first_name: Jacqueline-Claire
full_name: Montanaro-Punzengruber, Jacqueline-Claire
id: 3786AB44-F248-11E8-B48F-1D18A9856A87
last_name: Montanaro-Punzengruber
- first_name: Martin
full_name: Gassmann, Martin
last_name: Gassmann
- first_name: Peter M
full_name: Jonas, Peter M
id: 353C1B58-F248-11E8-B48F-1D18A9856A87
last_name: Jonas
orcid: 0000-0001-5001-4804
- first_name: Akos
full_name: Kulik, Akos
last_name: Kulik
- first_name: Bernhard
full_name: Bettler, Bernhard
last_name: Bettler
- first_name: Ryuichi
full_name: Shigemoto, Ryuichi
id: 499F3ABC-F248-11E8-B48F-1D18A9856A87
last_name: Shigemoto
orcid: 0000-0001-8761-9444
- first_name: Peter
full_name: Koppensteiner, Peter
id: 3B8B25A8-F248-11E8-B48F-1D18A9856A87
last_name: Koppensteiner
orcid: 0000-0002-3509-1948
citation:
ama: Bhandari P, Vandael DH, Fernández-Fernández D, et al. GABAB receptor auxiliary
subunits modulate Cav2.3-mediated release from medial habenula terminals. eLife.
2021;10. doi:10.7554/ELIFE.68274
apa: Bhandari, P., Vandael, D. H., Fernández-Fernández, D., Fritzius, T., Kleindienst,
D., Önal, H. C., … Koppensteiner, P. (2021). GABAB receptor auxiliary subunits
modulate Cav2.3-mediated release from medial habenula terminals. ELife.
eLife Sciences Publications. https://doi.org/10.7554/ELIFE.68274
chicago: Bhandari, Pradeep, David H Vandael, Diego Fernández-Fernández, Thorsten
Fritzius, David Kleindienst, Hüseyin C Önal, Jacqueline-Claire Montanaro-Punzengruber,
et al. “GABAB Receptor Auxiliary Subunits Modulate Cav2.3-Mediated Release from
Medial Habenula Terminals.” ELife. eLife Sciences Publications, 2021. https://doi.org/10.7554/ELIFE.68274.
ieee: P. Bhandari et al., “GABAB receptor auxiliary subunits modulate Cav2.3-mediated
release from medial habenula terminals,” eLife, vol. 10. eLife Sciences
Publications, 2021.
ista: Bhandari P, Vandael DH, Fernández-Fernández D, Fritzius T, Kleindienst D,
Önal HC, Montanaro-Punzengruber J-C, Gassmann M, Jonas PM, Kulik A, Bettler B,
Shigemoto R, Koppensteiner P. 2021. GABAB receptor auxiliary subunits modulate
Cav2.3-mediated release from medial habenula terminals. eLife. 10, e68274.
mla: Bhandari, Pradeep, et al. “GABAB Receptor Auxiliary Subunits Modulate Cav2.3-Mediated
Release from Medial Habenula Terminals.” ELife, vol. 10, e68274, eLife
Sciences Publications, 2021, doi:10.7554/ELIFE.68274.
short: P. Bhandari, D.H. Vandael, D. Fernández-Fernández, T. Fritzius, D. Kleindienst,
H.C. Önal, J.-C. Montanaro-Punzengruber, M. Gassmann, P.M. Jonas, A. Kulik, B.
Bettler, R. Shigemoto, P. Koppensteiner, ELife 10 (2021).
date_created: 2021-05-30T22:01:23Z
date_published: 2021-04-29T00:00:00Z
date_updated: 2024-03-25T23:30:16Z
day: '29'
ddc:
- '570'
department:
- _id: RySh
- _id: PeJo
doi: 10.7554/ELIFE.68274
ec_funded: 1
external_id:
isi:
- '000651761700001'
file:
- access_level: open_access
checksum: 6ebcb79999f889766f7cd79ee134ad28
content_type: application/pdf
creator: cziletti
date_created: 2021-05-31T09:43:09Z
date_updated: 2021-05-31T09:43:09Z
file_id: '9440'
file_name: 2021_eLife_Bhandari.pdf
file_size: 8174719
relation: main_file
success: 1
file_date_updated: 2021-05-31T09:43:09Z
has_accepted_license: '1'
intvolume: ' 10'
isi: 1
language:
- iso: eng
month: '04'
oa: 1
oa_version: Published Version
project:
- _id: 25CA28EA-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '694539'
name: 'In situ analysis of single channel subunit composition in neurons: physiological
implication in synaptic plasticity and behaviour'
- _id: 25B7EB9E-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '692692'
name: Biophysics and circuit function of a giant cortical glumatergic synapse
- _id: 2564DBCA-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '665385'
name: International IST Doctoral Program
publication: eLife
publication_identifier:
eissn:
- 2050-084X
publication_status: published
publisher: eLife Sciences Publications
quality_controlled: '1'
related_material:
link:
- relation: earlier_version
url: https://doi.org/10.1101/2020.04.16.045112
record:
- id: '9562'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: GABAB receptor auxiliary subunits modulate Cav2.3-mediated release from medial
habenula terminals
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 10
year: '2021'
...
---
_id: '8532'
abstract:
- lang: eng
text: The molecular anatomy of synapses defines their characteristics in transmission
and plasticity. Precise measurements of the number and distribution of synaptic
proteins are important for our understanding of synapse heterogeneity within and
between brain regions. Freeze–fracture replica immunogold electron microscopy
enables us to analyze them quantitatively on a two-dimensional membrane surface.
Here, we introduce Darea software, which utilizes deep learning for analysis of
replica images and demonstrate its usefulness for quick measurements of the pre-
and postsynaptic areas, density and distribution of gold particles at synapses
in a reproducible manner. We used Darea for comparing glutamate receptor and calcium
channel distributions between hippocampal CA3-CA1 spine synapses on apical and
basal dendrites, which differ in signaling pathways involved in synaptic plasticity.
We found that apical synapses express a higher density of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic
acid (AMPA) receptors and a stronger increase of AMPA receptors with synaptic
size, while basal synapses show a larger increase in N-methyl-D-aspartate (NMDA)
receptors with size. Interestingly, AMPA and NMDA receptors are segregated within
postsynaptic sites and negatively correlated in density among both apical and
basal synapses. In the presynaptic sites, Cav2.1 voltage-gated calcium channels
show similar densities in apical and basal synapses with distributions consistent
with an exclusion zone model of calcium channel-release site topography.
acknowledgement: "This research was funded by Austrian Academy of Sciences, DOC fellowship
to D.K., European Research\r\nCouncil Advanced Grant 694539 and European Union Human
Brain Project (HBP) SGA2 785907 to R.S.\r\nWe acknowledge Elena Hollergschwandtner
for technical support."
article_number: '6737'
article_processing_charge: No
article_type: original
author:
- first_name: David
full_name: Kleindienst, David
id: 42E121A4-F248-11E8-B48F-1D18A9856A87
last_name: Kleindienst
- first_name: Jacqueline-Claire
full_name: Montanaro-Punzengruber, Jacqueline-Claire
id: 3786AB44-F248-11E8-B48F-1D18A9856A87
last_name: Montanaro-Punzengruber
- first_name: Pradeep
full_name: Bhandari, Pradeep
id: 45EDD1BC-F248-11E8-B48F-1D18A9856A87
last_name: Bhandari
orcid: 0000-0003-0863-4481
- first_name: Matthew J
full_name: Case, Matthew J
id: 44B7CA5A-F248-11E8-B48F-1D18A9856A87
last_name: Case
- first_name: Yugo
full_name: Fukazawa, Yugo
last_name: Fukazawa
- first_name: Ryuichi
full_name: Shigemoto, Ryuichi
id: 499F3ABC-F248-11E8-B48F-1D18A9856A87
last_name: Shigemoto
orcid: 0000-0001-8761-9444
citation:
ama: Kleindienst D, Montanaro-Punzengruber J-C, Bhandari P, Case MJ, Fukazawa Y,
Shigemoto R. Deep learning-assisted high-throughput analysis of freeze-fracture
replica images applied to glutamate receptors and calcium channels at hippocampal
synapses. International Journal of Molecular Sciences. 2020;21(18). doi:10.3390/ijms21186737
apa: Kleindienst, D., Montanaro-Punzengruber, J.-C., Bhandari, P., Case, M. J.,
Fukazawa, Y., & Shigemoto, R. (2020). Deep learning-assisted high-throughput
analysis of freeze-fracture replica images applied to glutamate receptors and
calcium channels at hippocampal synapses. International Journal of Molecular
Sciences. MDPI. https://doi.org/10.3390/ijms21186737
chicago: Kleindienst, David, Jacqueline-Claire Montanaro-Punzengruber, Pradeep Bhandari,
Matthew J Case, Yugo Fukazawa, and Ryuichi Shigemoto. “Deep Learning-Assisted
High-Throughput Analysis of Freeze-Fracture Replica Images Applied to Glutamate
Receptors and Calcium Channels at Hippocampal Synapses.” International Journal
of Molecular Sciences. MDPI, 2020. https://doi.org/10.3390/ijms21186737.
ieee: D. Kleindienst, J.-C. Montanaro-Punzengruber, P. Bhandari, M. J. Case, Y.
Fukazawa, and R. Shigemoto, “Deep learning-assisted high-throughput analysis of
freeze-fracture replica images applied to glutamate receptors and calcium channels
at hippocampal synapses,” International Journal of Molecular Sciences,
vol. 21, no. 18. MDPI, 2020.
ista: Kleindienst D, Montanaro-Punzengruber J-C, Bhandari P, Case MJ, Fukazawa Y,
Shigemoto R. 2020. Deep learning-assisted high-throughput analysis of freeze-fracture
replica images applied to glutamate receptors and calcium channels at hippocampal
synapses. International Journal of Molecular Sciences. 21(18), 6737.
mla: Kleindienst, David, et al. “Deep Learning-Assisted High-Throughput Analysis
of Freeze-Fracture Replica Images Applied to Glutamate Receptors and Calcium Channels
at Hippocampal Synapses.” International Journal of Molecular Sciences,
vol. 21, no. 18, 6737, MDPI, 2020, doi:10.3390/ijms21186737.
short: D. Kleindienst, J.-C. Montanaro-Punzengruber, P. Bhandari, M.J. Case, Y.
Fukazawa, R. Shigemoto, International Journal of Molecular Sciences 21 (2020).
date_created: 2020-09-20T22:01:35Z
date_published: 2020-09-14T00:00:00Z
date_updated: 2024-03-25T23:30:16Z
day: '14'
ddc:
- '570'
department:
- _id: RySh
doi: 10.3390/ijms21186737
ec_funded: 1
external_id:
isi:
- '000579945300001'
file:
- access_level: open_access
checksum: 2e4f62f3cfe945b7391fc3070e5a289f
content_type: application/pdf
creator: dernst
date_created: 2020-09-21T14:08:58Z
date_updated: 2020-09-21T14:08:58Z
file_id: '8551'
file_name: 2020_JournMolecSciences_Kleindienst.pdf
file_size: 5748456
relation: main_file
success: 1
file_date_updated: 2020-09-21T14:08:58Z
has_accepted_license: '1'
intvolume: ' 21'
isi: 1
issue: '18'
language:
- iso: eng
month: '09'
oa: 1
oa_version: Published Version
project:
- _id: 25CA28EA-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '694539'
name: 'In situ analysis of single channel subunit composition in neurons: physiological
implication in synaptic plasticity and behaviour'
- _id: 25D32BC0-B435-11E9-9278-68D0E5697425
name: Mechanism of formation and maintenance of input side-dependent asymmetry in
the hippocampus
- _id: 26436750-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '785907'
name: Human Brain Project Specific Grant Agreement 2 (HBP SGA 2)
publication: International Journal of Molecular Sciences
publication_identifier:
eissn:
- '14220067'
issn:
- '16616596'
publication_status: published
publisher: MDPI
quality_controlled: '1'
related_material:
record:
- id: '9562'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: Deep learning-assisted high-throughput analysis of freeze-fracture replica
images applied to glutamate receptors and calcium channels at hippocampal synapses
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 21
year: '2020'
...
---
_id: '7525'
abstract:
- lang: eng
text: "The medial habenula (MHb) is an evolutionary conserved epithalamic structure
important for the modulation of emotional memory. It is involved in regulation
of anxiety, compulsive behavior, addiction (nicotinic and opioid), sexual and
feeding behavior. MHb receives inputs from septal regions and projects exclusively
to the interpeduncular nucleus (IPN). Distinct sub-regions of the septum project
to different subnuclei of MHb: the bed nucleus of anterior commissure projects
to dorsal MHb and the triangular septum projects to ventral MHb. Furthermore,
the dorsal and ventral MHb project to the lateral and rostral/central IPN, respectively.
Importantly, these projections have unique features of prominent co-release of
different neurotransmitters and requirement of a peculiar type of calcium channel
for release. In general, synaptic neurotransmission requires an activity-dependent
influx of Ca2+ into the presynaptic terminal through voltage-gated calcium channels.
The calcium channel family most commonly involved in neurotransmitter release
comprises three members, P/Q-, N- and R-type with Cav2.1, Cav2.2 and Cav2.3 subunits,
respectively. In contrast to most CNS synapses that mainly express Cav2.1 and/or
Cav2.2, MHb terminals in the IPN exclusively express Cav2.3. In other parts of
the brain, such as the hippocampus, Cav2.3 is mostly located to postsynaptic elements.
This unusual presynaptic location of Cav2.3 in the MHb-IPN pathway implies unique
mechanisms of glutamate release in this pathway. One potential example of such
uniqueness is the facilitation of release by GABAB receptor (GBR) activation.
Presynaptic GBRs usually inhibit the release of neurotransmitters by inhibiting
presynaptic calcium channels. MHb shows the highest expression levels of GBR in
the brain. GBRs comprise two subunits, GABAB1 (GB1) and GABAB2 (GB2), and are
associated with auxiliary subunits, called potassium channel tetramerization domain
containing proteins (KCTD) 8, 12, 12b and 16. Among these four subunits, KCTD12b
is exclusively expressed in ventral MHb, and KCTD8 shows the strongest expression
in the whole MHb among other brain regions, indicating that KCTD8 and KCTD12b
may be involved in the unique mechanisms of neurotransmitter release mediated
by Cav2.3 and regulated by GBRs in this pathway. \r\nIn the present study, we
first verified that neurotransmission in both dorsal and ventral MHb-IPN pathways
is mainly mediated by Cav2.3 using a selective blocker of R-type channels, SNX-482.
We next found that baclofen, a GBR agonist, has facilitatory effects on release
from ventral MHb terminal in rostral IPN, whereas it has inhibitory effects on
release from dorsal MHb terminals in lateral IPN, indicating that KCTD12b expressed
exclusively in ventral MHb may have a role in the facilitatory effects of GBR
activation. In a heterologous expression system using HEK cells, we found that
KCTD8 and KCTD12b but not KCTD12 directly bind with Cav2.3. Pre-embedding immunogold
electron microscopy data show that Cav2.3 and KCTD12b are distributed most densely
in presynaptic active zone in IPN with KCTD12b being present only in rostral/central
but not lateral IPN, whereas GABAB, KCTD8 and KCTD12 are distributed most densely
in perisynaptic sites with KCTD12 present more frequently in postsynaptic elements
and only in rostral/central IPN. In freeze-fracture replica labelling, Cav2.3,
KCTD8 and KCTD12b are co-localized with each other in the same active zone indicating
that they may form complexes regulating vesicle release in rostral IPN. \r\nOn
electrophysiological studies of wild type (WT) mice, we found that paired-pulse
ratio in rostral IPN of KCTD12b knock-out (KO) mice is lower than those of WT
and KCTD8 KO mice. Consistent with this finding, in mean variance analysis, release
probability in rostral IPN of KCTD12b KO mice is higher than that of WT and KCTD8
KO mice. Although paired-pulse ratios are not different between WT and KCTD8 KO
mice, the mean variance analysis revealed significantly lower release probability
in rostral IPN of KCTD8 KO than WT mice. These results demonstrate bidirectional
regulation of Cav2.3-mediated release by KCTD8 and KCTD12b without GBR activation
in rostral IPN. Finally, we examined the baclofen effects in rostral IPN of KCTD8
and KCTD12b KO mice, and found the facilitation of release remained in both KO
mice, indicating that the peculiar effects of the GBR activation in this pathway
do not depend on the selective expression of these KCTD subunits in ventral MHb.
However, we found that presynaptic potentiation of evoked EPSC amplitude by baclofen
falls to baseline after washout faster in KCTD12b KO mice than WT, KCTD8 KO and
KCTD8/12b double KO mice. This result indicates that KCTD12b is involved in sustained
potentiation of vesicle release by GBR activation, whereas KCTD8 is involved in
its termination in the absence of KCTD12b. Consistent with these functional findings,
replica labelling revealed an increase in density of KCTD8, but not Cav2.3 or
GBR at active zone in rostral IPN of KCTD12b KO mice compared with that of WT
mice, suggesting that increased association of KCTD8 with Cav2.3 facilitates the
release probability and termination of the GBR effect in the absence of KCTD12b.\r\nIn
summary, our study provided new insights into the physiological roles of presynaptic
Cav2.3, GBRs and their auxiliary subunits KCTDs at an evolutionary conserved neuronal
circuit. Future studies will be required to identify the exact molecular mechanism
underlying the GBR-mediated presynaptic potentiation on ventral MHb terminals.
It remains to be determined whether the prominent presence of presynaptic KCTDs
at active zone could exert similar neuromodulatory functions in different pathways
of the brain.\r\n"
acknowledged_ssus:
- _id: EM-Fac
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Pradeep
full_name: Bhandari, Pradeep
id: 45EDD1BC-F248-11E8-B48F-1D18A9856A87
last_name: Bhandari
orcid: 0000-0003-0863-4481
citation:
ama: Bhandari P. Localization and functional role of Cav2.3 in the medial habenula
to interpeduncular nucleus pathway. 2020. doi:10.15479/AT:ISTA:7525
apa: Bhandari, P. (2020). Localization and functional role of Cav2.3 in the medial
habenula to interpeduncular nucleus pathway. Institute of Science and Technology
Austria. https://doi.org/10.15479/AT:ISTA:7525
chicago: Bhandari, Pradeep. “Localization and Functional Role of Cav2.3 in the Medial
Habenula to Interpeduncular Nucleus Pathway.” Institute of Science and Technology
Austria, 2020. https://doi.org/10.15479/AT:ISTA:7525.
ieee: P. Bhandari, “Localization and functional role of Cav2.3 in the medial habenula
to interpeduncular nucleus pathway,” Institute of Science and Technology Austria,
2020.
ista: Bhandari P. 2020. Localization and functional role of Cav2.3 in the medial
habenula to interpeduncular nucleus pathway. Institute of Science and Technology
Austria.
mla: Bhandari, Pradeep. Localization and Functional Role of Cav2.3 in the Medial
Habenula to Interpeduncular Nucleus Pathway. Institute of Science and Technology
Austria, 2020, doi:10.15479/AT:ISTA:7525.
short: P. Bhandari, Localization and Functional Role of Cav2.3 in the Medial Habenula
to Interpeduncular Nucleus Pathway, Institute of Science and Technology Austria,
2020.
date_created: 2020-02-26T10:56:37Z
date_published: 2020-02-28T00:00:00Z
date_updated: 2023-09-07T13:20:03Z
day: '28'
ddc:
- '570'
degree_awarded: PhD
department:
- _id: RySh
doi: 10.15479/AT:ISTA:7525
file:
- access_level: open_access
checksum: 4589234fdb12b4ad72273b311723a7b4
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creator: pbhandari
date_created: 2020-02-28T08:37:53Z
date_updated: 2021-03-01T23:30:04Z
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title: Localization and functional role of Cav2.3 in the medial habenula to interpeduncular
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content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document
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date_created: 2020-02-28T08:47:14Z
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title: Localization and functional role of Cav2.3 in the medial habenula to interpeduncular
nucleus pathway
file_date_updated: 2021-03-01T23:30:04Z
has_accepted_license: '1'
keyword:
- Cav2.3
- medial habenula (MHb)
- interpeduncular nucleus (IPN)
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
page: '79'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
status: public
supervisor:
- first_name: Ryuichi
full_name: Shigemoto, Ryuichi
id: 499F3ABC-F248-11E8-B48F-1D18A9856A87
last_name: Shigemoto
orcid: 0000-0001-8761-9444
title: Localization and functional role of Cav2.3 in the medial habenula to interpeduncular
nucleus pathway
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2020'
...