Equilibrium unfolding of the PDZ domain of β2-syntrophin

Autores
Torchio, Gabriela María; Ermácora, Mario Roberto; Sica, Mauricio Pablo
Año de publicación
2012
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
β2-syntrophin, a dystrophin-associated protein, plays a pivotal role in insulin secretion by pancreatic β-cells. It contains a PDZ domain (β2S-PDZ) that, in complex with protein-tyrosine phosphatase ICA512, anchors the dense insulin granules to actin filaments. The phosphorylation state of β2-syntrophin allosterically regulates the affinity of β2S-PDZ for ICA512, and the disruption of the complex triggers the mobilization of the insulin granule stores. Here, we investigate the thermal unfolding of β2S-PDZ at different pH and urea concentrations. Our results indicate that, unlike other PDZ domains, β2S-PDZ is marginally stable. Thermal denaturation experiments show broad transitions and cold denaturation, and a two-state model fit reveals a significant unfolded fraction under physiological conditions. Furthermore, Tm and Tmax denaturant-dependent shifts and noncoincidence of melting curves monitored at different wavelengths suggest that two-state and three-state models fail to explain the equilibrium data properly and are in better agreement with a downhill scenario. Its higher stability at pH > 9 and the results of molecular dynamics simulations indicate that this behavior of β2S-PDZ might be related to its charge distribution. All together, our results suggest a link between the conformational plasticity of the native ensemble of this PDZ domain and the regulation of insulin secretion.
Instituto Multidisciplinario de Biología Celular
Materia
Ciencias Exactas
β2-syntrophin
PDZ domain
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/87841
Acceder
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oai_identifier_str oai:sedici.unlp.edu.ar:10915/87841
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Equilibrium unfolding of the PDZ domain of β2-syntrophinTorchio, Gabriela MaríaErmácora, Mario RobertoSica, Mauricio PabloCiencias Exactasβ2-syntrophinPDZ domainβ2-syntrophin, a dystrophin-associated protein, plays a pivotal role in insulin secretion by pancreatic β-cells. It contains a PDZ domain (β2S-PDZ) that, in complex with protein-tyrosine phosphatase ICA512, anchors the dense insulin granules to actin filaments. The phosphorylation state of β2-syntrophin allosterically regulates the affinity of β2S-PDZ for ICA512, and the disruption of the complex triggers the mobilization of the insulin granule stores. Here, we investigate the thermal unfolding of β2S-PDZ at different pH and urea concentrations. Our results indicate that, unlike other PDZ domains, β2S-PDZ is marginally stable. Thermal denaturation experiments show broad transitions and cold denaturation, and a two-state model fit reveals a significant unfolded fraction under physiological conditions. Furthermore, T<sub>m</sub> and T<sub>max</sub> denaturant-dependent shifts and noncoincidence of melting curves monitored at different wavelengths suggest that two-state and three-state models fail to explain the equilibrium data properly and are in better agreement with a downhill scenario. Its higher stability at pH > 9 and the results of molecular dynamics simulations indicate that this behavior of β2S-PDZ might be related to its charge distribution. All together, our results suggest a link between the conformational plasticity of the native ensemble of this PDZ domain and the regulation of insulin secretion.Instituto Multidisciplinario de Biología Celular2012info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf2835-2844http://sedici.unlp.edu.ar/handle/10915/87841enginfo:eu-repo/semantics/altIdentifier/issn/0006-3495info:eu-repo/semantics/altIdentifier/doi/10.1016/j.bpj.2012.05.021info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-10-22T16:56:52Zoai:sedici.unlp.edu.ar:10915/87841Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-10-22 16:56:53.153SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Equilibrium unfolding of the PDZ domain of β2-syntrophin
title Equilibrium unfolding of the PDZ domain of β2-syntrophin
spellingShingle Equilibrium unfolding of the PDZ domain of β2-syntrophin
Torchio, Gabriela María
Ciencias Exactas
β2-syntrophin
PDZ domain
title_short Equilibrium unfolding of the PDZ domain of β2-syntrophin
title_full Equilibrium unfolding of the PDZ domain of β2-syntrophin
title_fullStr Equilibrium unfolding of the PDZ domain of β2-syntrophin
title_full_unstemmed Equilibrium unfolding of the PDZ domain of β2-syntrophin
title_sort Equilibrium unfolding of the PDZ domain of β2-syntrophin
dc.creator.none.fl_str_mv Torchio, Gabriela María
Ermácora, Mario Roberto
Sica, Mauricio Pablo
author Torchio, Gabriela María
author_facet Torchio, Gabriela María
Ermácora, Mario Roberto
Sica, Mauricio Pablo
author_role author
author2 Ermácora, Mario Roberto
Sica, Mauricio Pablo
author2_role author
author
dc.subject.none.fl_str_mv Ciencias Exactas
β2-syntrophin
PDZ domain
topic Ciencias Exactas
β2-syntrophin
PDZ domain
dc.description.none.fl_txt_mv β2-syntrophin, a dystrophin-associated protein, plays a pivotal role in insulin secretion by pancreatic β-cells. It contains a PDZ domain (β2S-PDZ) that, in complex with protein-tyrosine phosphatase ICA512, anchors the dense insulin granules to actin filaments. The phosphorylation state of β2-syntrophin allosterically regulates the affinity of β2S-PDZ for ICA512, and the disruption of the complex triggers the mobilization of the insulin granule stores. Here, we investigate the thermal unfolding of β2S-PDZ at different pH and urea concentrations. Our results indicate that, unlike other PDZ domains, β2S-PDZ is marginally stable. Thermal denaturation experiments show broad transitions and cold denaturation, and a two-state model fit reveals a significant unfolded fraction under physiological conditions. Furthermore, T<sub>m</sub> and T<sub>max</sub> denaturant-dependent shifts and noncoincidence of melting curves monitored at different wavelengths suggest that two-state and three-state models fail to explain the equilibrium data properly and are in better agreement with a downhill scenario. Its higher stability at pH > 9 and the results of molecular dynamics simulations indicate that this behavior of β2S-PDZ might be related to its charge distribution. All together, our results suggest a link between the conformational plasticity of the native ensemble of this PDZ domain and the regulation of insulin secretion.
Instituto Multidisciplinario de Biología Celular
description β2-syntrophin, a dystrophin-associated protein, plays a pivotal role in insulin secretion by pancreatic β-cells. It contains a PDZ domain (β2S-PDZ) that, in complex with protein-tyrosine phosphatase ICA512, anchors the dense insulin granules to actin filaments. The phosphorylation state of β2-syntrophin allosterically regulates the affinity of β2S-PDZ for ICA512, and the disruption of the complex triggers the mobilization of the insulin granule stores. Here, we investigate the thermal unfolding of β2S-PDZ at different pH and urea concentrations. Our results indicate that, unlike other PDZ domains, β2S-PDZ is marginally stable. Thermal denaturation experiments show broad transitions and cold denaturation, and a two-state model fit reveals a significant unfolded fraction under physiological conditions. Furthermore, T<sub>m</sub> and T<sub>max</sub> denaturant-dependent shifts and noncoincidence of melting curves monitored at different wavelengths suggest that two-state and three-state models fail to explain the equilibrium data properly and are in better agreement with a downhill scenario. Its higher stability at pH > 9 and the results of molecular dynamics simulations indicate that this behavior of β2S-PDZ might be related to its charge distribution. All together, our results suggest a link between the conformational plasticity of the native ensemble of this PDZ domain and the regulation of insulin secretion.
publishDate 2012
dc.date.none.fl_str_mv 2012
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/87841
url http://sedici.unlp.edu.ar/handle/10915/87841
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0006-3495
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.bpj.2012.05.021
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
2835-2844
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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