Protein misfolding is a central feature of most neurodegenerative diseases. Molecular chaperones can modulate the toxicity associated with protein misfolding, but it remains elusive which molecular chaperones and co-chaperones interact with specific misfolded proteins. TDP-43 misfolding and inclusion formation are a hallmark of amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases. Using yeast and mammalian neuronal cells we find that Hsp90 and its co-chaperone Sti1 have the capacity to alter TDP-43 misfolding, inclusion formation, aggregation, and cellular toxicity. Our data also demonstrate that impaired Hsp90 function sensitizes cells to TDP-43 toxicity and that Sti1 specifically interacts with and strongly modulates TDP-43 toxicity in a dose-dependent manner. Our study thus uncovers a previously unrecognized tie between Hsp90, Sti1, TDP-43 misfolding, and cellular toxicity.
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http://dx.doi.org/10.1096/fj.202002645R | DOI Listing |
Eur J Neurosci
January 2025
Department of Genetics and Evolution and Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland.
The misfolding and aggregation of TAR DNA binding protein-43 (TDP-43), leading to the formation of cytoplasmic inclusions, emerge as a key pathological feature in a spectrum of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar dementia (FTLD). TDP-43 shuttles between the nucleus and cytoplasm but forms nuclear bodies (NBs) in response to stress. These NBs partially colocalise with nuclear speckles and paraspeckles that sequester RNAs and proteins, thereby regulating many cellular functions.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.
Changes in water-protein interactions are crucial for proteins to achieve functional and nonfunctional conformations during structural transitions by modulating local stability. Amyloid-like protein aggregates in deteriorating neurons are hallmarks of neurodegenerative disorders. These aggregates form through significant structural changes, transitioning from functional native conformations to supramolecular cross-β-sheet structures via misfolded and oligomeric intermediates in a multistep process.
View Article and Find Full Text PDFTDP-43 is linked to human diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). Expression of TDP-43 in yeast is known to be toxic, cause cells to elongate, form liquid-like aggregates, and inhibit autophagy and TOROID formation. Here, we used the yeast model of disorders of inborn errors of metabolism, previously shown to lead to intracellular adenine accumulation and adenine amyloid-like fiber formation, to explore interactions with TDP-43.
View Article and Find Full Text PDFPathology
November 2024
Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, ON, Canada; Laboratory Medicine Program and Krembil Brain Institute, University Health Network, Toronto, ON, Canada; Dementia Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia; Edmond J. Safra Program in Parkinson's Disease, Rossy PSP Centre and the Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology and Department of Medicine, University of Toronto, Toronto, ON, Canada. Electronic address:
Neurodegenerative diseases are a pathologically, clinically and genetically diverse group of diseases characterised by selective dysfunction, loss of synaptic connectivity and neurodegeneration, and are associated with the deposition of misfolded proteins in neurons and/or glia. Molecular studies have highlighted the role of conformationally altered proteins in the pathogenesis of neurodegenerative diseases and have paved the way for developing disease-specific biomarkers that capture and differentiate the main type/s of protein abnormality responsible for neurodegenerative diseases, some of which are currently used in clinical practice. These proteins follow sequential patterns of anatomical involvement and disease spread in the brain and may also be detected in peripheral organs.
View Article and Find Full Text PDFBrain Commun
December 2024
Laboratory for Neuropathology, Department of Imaging and Pathology, KU Leuven, Leuven 3000, Belgium.
Misfolded α-synuclein protein accumulates in 43-63% of individuals with symptomatic Alzheimer's disease. Two main patterns of comorbid α-synuclein pathology have been identified: caudo-rostral and amygdala-predominant. α-Synuclein aggregates have been shown to interact with the transactive response DNA-binding protein 43 (TDP-43) and abnormally phosphorylated tau protein.
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