Glycogen synthase kinase 3-mediated voltage-dependent anion channel phosphorylation controls outer mitochondrial membrane permeability during lipid accumulation. - Université Paris Cité Accéder directement au contenu
Article Dans Une Revue Hepatology Année : 2013

Glycogen synthase kinase 3-mediated voltage-dependent anion channel phosphorylation controls outer mitochondrial membrane permeability during lipid accumulation.

Résumé

UNLABELLED: Nonalcoholic steatosis is a liver pathology characterized by fat accumulation and severe metabolic alterations involving early mitochondrial impairment and late hepatocyte cell death. However, mitochondrial dysfunction mechanisms remain elusive. Using four models of nonalcoholic steatosis, i.e., livers from patients with fatty liver disease, ob/ob mice, mice fed a high-fat diet, and in vitro models of lipotoxicity, we show that outer mitochondrial membrane permeability is altered and identified a posttranslational modification of voltage-dependent anion channel (VDAC), a membrane channel and NADH oxidase, as a cause of early mitochondrial dysfunction. Thus, in nonalcoholic steatosis VDAC exhibits reduced threonine phosphorylation, which increases the influx of water and calcium into mitochondria, sensitizes the organelle to matrix swelling, depolarization, and cytochrome c release without inducing cell death. This also amplifies VDAC enzymatic and channel activities regulation by calcium and modifies its interaction with proteic partners. Moreover, lipid accumulation triggers a rapid lack of VDAC phosphorylation by glycogen synthase kinase 3 (GSK3). Pharmacological and genetic manipulations proved GSK3 to be responsible for VDAC phosphorylation in normal cells. Notably, VDAC phosphorylation level correlated with steatosis severity in patients. CONCLUSION: VDAC acts as an early sensor of lipid toxicity and its GSK3-mediated phosphorylation status controls outer mitochondrial membrane permeabilization in hepatosteatosis.
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Dates et versions

hal-00734262 , version 1 (21-09-2012)

Identifiants

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Cecile Martel, Maya Allouche, Davide Degli Esposti, Elena Fanelli, Céline Boursier, et al.. Glycogen synthase kinase 3-mediated voltage-dependent anion channel phosphorylation controls outer mitochondrial membrane permeability during lipid accumulation.. Hepatology, 2013, 57 (1), pp.93-102. ⟨10.1002/hep.25967⟩. ⟨hal-00734262⟩
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