Regulation of Endoplasmic Reticulum-Mitochondria Tethering and Ca2+ Fluxes by TDP-43 via GSK3ß.
Int J Mol Sci
; 22(21)2021 Nov 01.
Article
em En
| MEDLINE
| ID: mdl-34769284
ABSTRACT
Mitochondria-ER contacts (MERCs), tightly regulated by numerous tethering proteins that act as molecular and functional connections between the two organelles, are essential to maintain a variety of cellular functions. Such contacts are often compromised in the early stages of many neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). TDP-43, a nuclear protein mainly involved in RNA metabolism, has been repeatedly associated with ALS pathogenesis and other neurodegenerative diseases. Although TDP-43 neuropathological mechanisms are still unclear, the accumulation of the protein in cytoplasmic inclusions may underlie a protein loss-of-function effect. Accordingly, we investigated the impact of siRNA-mediated TDP-43 silencing on MERCs and the related cellular parameters in HeLa cells using GFP-based probes for MERCs quantification and aequorin-based probes for local Ca2+ measurements, combined with targeted protein and mRNA profiling. Our results demonstrated that TDP-43 down-regulation decreases MERCs density, thereby remarkably reducing mitochondria Ca2+ uptake after ER Ca2+ release. Thorough mRNA and protein analyses did not highlight altered expression of proteins involved in MERCs assembly or Ca2+-mediated ER-mitochondria cross-talk, nor alterations of mitochondrial density and morphology were observed by confocal microscopy. Further mechanistic inspections, however, suggested that the observed cellular alterations are correlated to increased expression/activity of GSK3ß, previously associated with MERCs disruption.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cálcio
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Proteínas de Ligação a DNA
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Glicogênio Sintase Quinase 3 beta
Limite:
Humans
Idioma:
En
Revista:
Int J Mol Sci
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Itália