Localization and functional consequences of a direct interaction between TRIOBP-1 and hERG proteins in the heart.
J Cell Sci
; 131(6)2018 03 22.
Article
en En
| MEDLINE
| ID: mdl-29507111
ABSTRACT
Reduced levels of the cardiac human (h)ERG ion channel protein and the corresponding repolarizing current IKr can cause arrhythmia and sudden cardiac death, but the underlying cellular mechanisms controlling hERG surface expression are not well understood. Here, we identified TRIOBP-1, an F-actin-binding protein previously associated with actin polymerization, as a putative hERG-interacting protein in a yeast-two hybrid screen of a cardiac library. We corroborated this interaction by performing Förster resonance energy transfer (FRET) in HEK293 cells and co-immunoprecipitation in HEK293 cells and native cardiac tissue. TRIOBP-1 overexpression reduced hERG surface expression and current density, whereas reducing TRIOBP-1 expression via shRNA knockdown resulted in increased hERG protein levels. Immunolabeling in rat cardiomyocytes showed that native TRIOBP-1 colocalized predominantly with myosin-binding protein C and secondarily with rat ERG. In human stem cell-derived cardiomyocytes, TRIOBP-1 overexpression caused intracellular co-sequestration of hERG signal, reduced native IKr and disrupted action potential repolarization. Ca2+ currents were also somewhat reduced and cell capacitance was increased. These findings establish that TRIOBP-1 interacts directly with hERG and can affect protein levels, IKr magnitude and cardiac membrane excitability.
Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Miocitos Cardíacos
/
Proteínas de Microfilamentos
Tipo de estudio:
Prognostic_studies
Límite:
Animals
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Humans
/
Male
Idioma:
En
Revista:
J Cell Sci
Año:
2018
Tipo del documento:
Article
País de afiliación:
Estados Unidos