A glaucoma- and ALS-associated mutant of OPTN induces neuronal cell death dependent on Tbk1 activity, autophagy and ER stress
| Autor: | Priyanka Tare, Zuberwasim Sayyad, Ghanshyam Swarup, Swetha Medchalmi |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
Programmed cell death Mutant ATG5 Apoptosis Cell Cycle Proteins CHOP Protein Serine-Threonine Kinases Biochemistry Autophagy-Related Protein 5 03 medical and health sciences 0302 clinical medicine Autophagy Humans Molecular Biology Optineurin Neurons Chemistry Amyotrophic Lateral Sclerosis Membrane Transport Proteins Glaucoma Cell Biology Endoplasmic Reticulum Stress Cell biology 030104 developmental biology HEK293 Cells Cytoplasm 030220 oncology & carcinogenesis Mutation Unfolded protein response Microtubule-Associated Proteins Transcription Factor CHOP Protein Binding |
| Zdroj: | The FEBS journalReferences. 288(15) |
| ISSN: | 1742-4658 |
| Popis: | Mutations in OPTN are associated with glaucoma, an eye disease, and also with amyotrophic lateral sclerosis (ALS), a motor neuron disease. A 2-bp insertion in OPTN (691_692insAG or 2bpIns-OPTN) is associated with both glaucoma and ALS. This mutation results in frame shift after 127 amino acids, giving rise to a protein with C-terminal aberrant sequence. We have explored the mechanism of induction of cell death by this mutant in a motor neuron cell line, NSC-34, and also in a retinal cell line, 661W. Compared to wild-type OPTN, this mutant induced more cell death in NSC-34 and 661W cells. This mutant localizes predominantly in the nucleus whereas normal OPTN localizes in the cytoplasm. Deletion analysis of 2bpIns-OPTN showed that the aberrant sequence was not essential for cell death induction. This mutant interacts with TANK-binding kinase 1 (Tbk1) but not with OPTN and activates Tbk1. This mutant induced ER stress in NSC-34 cells as seen by induction of C/EBP homologous protein (CHOP) and some other genes. Induction of CHOP, autophagosomal protein LC3-II and cell death by this mutant were abrogated by Tbk1 knockdown and also by 4-phenylbutyric acid, that inhibits ER stress. Induction of CHOP and cell death by 2bpIns-OPTN was autophagy dependent as shown by the effect of Atg5 knockdown. This mutant caused increased formation of LC3-positive aggregates. Treatment of cells with autophagy inducer rapamycin reduced LC3-positive aggregates, CHOP and cell death induced by 2bpIns-OPTN. These results suggest that constitutive activation of Tbk1 by 2bpIns-OPTN leads to impaired autophagy that results in ER stress and cell death. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|