Related Experiment Video
Updated: Feb 21, 2026
Fractionation for Resolution of Soluble and Insoluble Huntingtin Species
Published on: February 27, 2018
Post-translational modifications clustering within proteolytic domains decrease mutant huntingtin toxicity
Nicolas Arbez1, Tamara Ratovitski2, Elaine Roby2
1From the Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, narbez1@jhmi.edu.
Insights
Altering specific phosphorylation and acetylation sites on the huntingtin (Htt) protein can block neuronal toxicity and mitochondrial dysfunction in Huntington
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Huntington's disease (HD) is a neurodegenerative disorder primarily caused by polyglutamine expansion in the huntingtin (Htt) protein.
- Post-translational modifications (PTMs) significantly influence protein function and cellular pathways; their role in mutant Htt pathogenesis is critical.
- Previous studies suggest that modifying PTMs on Htt fragments can alter its cellular localization and toxicity.
Purpose of the Study:
- To systematically investigate the impact of altering individual phosphorylation and acetylation sites on full-length Htt.
- To assess how these PTM alterations affect neuronal toxicity and mitochondrial viability in the context of Huntington's disease.
- To identify specific PTMs that modulate mutant Htt's pathogenic effects.
Main Methods:
- Site-directed mutagenesis was used to alter individual phosphorylation and acetylation sites in full-length Htt constructs.
- Functional assays, including a nuclear condensation assay, were employed to measure cell toxicity.
- Mitochondrial viability was assessed by measuring mitochondrial membrane potential and size in primary neurons.
Main Results:
- Alterations in specific PTM sites on Htt significantly reduced neuronal toxicity.
- Modifying certain PTMs prevented mitochondrial dysfunction, including loss of potential and swelling, caused by mutant Htt.
- Key PTM sites, including previously known (Serine 116) and newly identified (Serine 2652) sites, were found to be critical modulators of Htt toxicity and are clustered in protease-sensitive domains.
Conclusions:
- Specific PTMs on the huntingtin protein play a crucial role in modulating Huntington's disease pathogenesis.
- Targeting these identified PTMs offers a potential therapeutic strategy for Huntington's disease.
- This research deepens the understanding of the Htt PTM code and its implications for neurodegenerative disease.
Abstract:
Huntington's disease (HD) is caused in large part by a polyglutamine expansion within the huntingtin (Htt) protein. Post-translational modifications (PTMs) control and regulate many protein functions and cellular pathways, and PTMs of mutant Htt are likely important modulators of HD pathogenesis. Alterations of selected numbers of PTMs of Htt fragments have been shown to modulate Htt cellular localization and toxicity. In this study, we systematically introduced site-directed alterations in individual phosphorylation and acetylation sites in full-length Htt constructs. The effects of each of these PTM alteration constructs were tested on cell toxicity using our nuclear condensation assay and on mitochondrial viability by measuring mitochondrial potential and size. Using these functional assays in primary neurons, we identified several PTMs whose alteration can block neuronal toxicity and prevent potential loss and swelling of the mitochondria caused by mutant Htt. These PTMs included previously described sites such as serine 116 and newly found sites such as serine 2652 throughout the protein. We found that these functionally relevant sites are clustered in protease-sensitive domains throughout full-length Htt. These findings advance our understanding of the Htt PTM code and its role in HD pathogenesis. Because PTMs are catalyzed by enzymes, the toxicity-modulating Htt PTMs identified here may be promising therapeutic targets for managing HD.
More Related Videos
10:52Efficient and Scalable Production of Full-length Human Huntingtin Variants in Mammalian Cells using a Transient Expression System
Published on: December 10, 2021
11:22Generation of Native, Untagged Huntingtin Exon1 Monomer and Fibrils Using a SUMO Fusion Strategy
Published on: June 27, 2018
