The basal flux of Akt in the mitochondria is mediated by heat shock protein 90
| Autor: | Gautam N. Bijur, Keri A. Barksdale |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Small interfering RNA
Lactams Macrocyclic Biology Mitochondrion Transfection Biochemistry Article Cell Line Mice Neuroblastoma Cellular and Molecular Neuroscience chemistry.chemical_compound Microscopy Electron Transmission Heat shock protein Benzoquinones Animals Humans Pyruvate Dehydrogenase (Lipoamide) HSP90 Heat-Shock Proteins Enzyme Inhibitors RNA Small Interfering Protein kinase B PI3K/AKT/mTOR pathway Injections Intraventricular Geldanamycin Hsp90 Mitochondria Cell biology Mice Inbred C57BL Oncogene Protein v-akt Cytosol chemistry biology.protein Intercellular Signaling Peptides and Proteins Novobiocin |
| Zdroj: | Journal of Neurochemistry. 108:1289-1299 |
| ISSN: | 1471-4159 0022-3042 |
| DOI: | 10.1111/j.1471-4159.2009.05878.x |
| Popis: | Akt is a known client protein of heat shock protein 90 (HSP90). We have found that HSP90 is responsible for Akt accumulation in the mitochondria in unstimulated cells. Treatment of SH-SY5Y neuroblastoma cells and human embryonic kidney cells with the HSP90 inhibitors novobiocin and geldanamycin caused substantial decreases in the level of Akt in the mitochondria without affecting the level of Akt in the cytosol. Moreover, intracerebroventricular injection of novobiocin into mice brains decreased Akt levels in cortical mitochondria. Knockdown of HSP90 expression with short interfering RNA also caused a significant decrease in Akt levels in the mitochondria without affecting total Akt levels. Using a mitochondrial import assay it was found that Akt is transported into the mitochondria. Furthermore, it was found that the mitochondrial import of Akt was independent of Akt activation as both an unmodified Akt and constitutively active mutant Akt; both readily accumulated in the mitochondria in an HSP90-dependent manner. Interestingly, incubation of isolated mitochondria with constitutively active Akt caused visible alterations in mitochondrial morphology, including pronounced remodeling of the mitochondrial matrix. This effect was blocked when Akt was mostly excluded from the mitochondria with novobiocin treatment. These results indicate that the level of Akt in the mitochondria is dependent on HSP90 chaperoning activity and that Akt import can cause dynamic changes in mitochondrial configuration. |
| Databáze: | OpenAIRE |
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