scholarly journals Identification of Full-Length Wild-Type and Mutant Huntingtin Interacting Proteins by Crosslinking Immunoprecipitation in Mice Brain Cortex

2021 ◽  
pp. 1-13
Author(s):  
Karen A. Sap ◽  
Arzu Tugce Guler ◽  
Aleksandra Bury ◽  
Dick Dekkers ◽  
Jeroen A.A. Demmers ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Brain Cortex ◽  
Full Length ◽  
Biological Processes ◽  
Interacting Proteins ◽  
Mutant Huntingtin ◽  
Wild Type ◽  
Mutant Huntingtin Protein ◽  
Mice Brain

Background: Huntington’s disease is a neurodegenerative disorder caused by a CAG expansion in the huntingtin gene, resulting in a polyglutamine expansion in the ubiquitously expressed mutant huntingtin protein. Objective: Here we set out to identify proteins interacting with the full-length wild-type and mutant huntingtin protein in the mice cortex brain region to understand affected biological processes in Huntington’s disease pathology. Methods: Full-length huntingtin with 20 and 140 polyQ repeats were formaldehyde-crosslinked and isolated via their N-terminal Flag-tag from 2-month-old mice brain cortex. Interacting proteins were identified and quantified by label-free liquid chromatography-mass spectrometry (LC-MS/MS). Results: We identified 30 interactors specific for wild-type huntingtin, 14 interactors specific for mutant huntingtin and 14 shared interactors that interacted with both wild-type and mutant huntingtin, including known interactors such as F8a1/Hap40. Syt1, Ykt6, and Snap47, involved in vesicle transport and exocytosis, were among the proteins that interacted specifically with wild-type huntingtin. Various other proteins involved in energy metabolism and mitochondria were also found to associate predominantly with wild-type huntingtin, whereas mutant huntingtin interacted with proteins involved in translation including Mapk3, Eif3h and Eef1a2. Conclusion: Here we identified both shared and specific interactors of wild-type and mutant huntingtin, which are involved in different biological processes including exocytosis, vesicle transport, translation and metabolism. These findings contribute to the understanding of the roles that wild-type and mutant huntingtin play in a variety of cellular processes both in healthy conditions and Huntington’s disease pathology.

scholarly journals The pathobiology of perturbed mutant huntingtin protein–protein interactions in Huntington's disease

2019 ◽  
Vol 151 (4) ◽  
pp. 507-519 ◽  
Author(s):  
Erich E. Wanker ◽  
Anne Ast ◽  
Franziska Schindler ◽  
Philipp Trepte ◽  
Sigrid Schnoegl
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Protein Interactions ◽  
Mutant Huntingtin ◽  
Protein Protein Interactions ◽  
Huntingtin Protein ◽  
Mutant Huntingtin Protein

scholarly journals Conformational studies of pathogenic expanded polyglutamine protein deposits from Huntington’s disease

2019 ◽  
Vol 244 (17) ◽  
pp. 1584-1595 ◽  
Author(s):  
Irina Matlahov ◽  
Patrick CA van der Wel
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Structural Biology ◽  
Age Of Onset ◽  
Repeat Expansion ◽  
Cag Repeat ◽  
Mutant Huntingtin ◽  
Cag Repeat Expansion ◽  
Recent Developments ◽  
Mutant Huntingtin Protein

Huntington’s disease, like other neurodegenerative diseases, continues to lack an effective cure. Current treatments that address early symptoms ultimately fail Huntington’s disease patients and their families, with the disease typically being fatal within 10–15 years from onset. Huntington’s disease is an inherited disorder with motor and mental impairment, and is associated with the genetic expansion of a CAG codon repeat encoding a polyglutamine-segment-containing protein called huntingtin. These Huntington’s disease mutations cause misfolding and aggregation of fragments of the mutant huntingtin protein, thereby likely contributing to disease toxicity through a combination of gain-of-toxic-function for the misfolded aggregates and a loss of function from sequestration of huntingtin and other proteins. As with other amyloid diseases, the mutant protein forms non-native fibrillar structures, which in Huntington’s disease are found within patients’ neurons. The intracellular deposits are associated with dysregulation of vital processes, and inter-neuronal transport of aggregates may contribute to disease progression. However, a molecular understanding of these aggregates and their detrimental effects has been frustrated by insufficient structural data on the misfolded protein state. In this review, we examine recent developments in the structural biology of polyglutamine-expanded huntingtin fragments, and especially the contributions enabled by advances in solid-state nuclear magnetic resonance spectroscopy. We summarize and discuss our current structural understanding of the huntingtin deposits and how this information furthers our understanding of the misfolding mechanism and disease toxicity mechanisms. Impact statement Many incurable neurodegenerative disorders are associated with, and potentially caused by, the amyloidogenic misfolding and aggregation of proteins. Usually, complex genetic and behavioral factors dictate disease risk and age of onset. Due to its principally mono-genic origin, which strongly predicts the age-of-onset by the extent of CAG repeat expansion, Huntington’s disease (HD) presents a unique opportunity to dissect the underlying disease-causing processes in molecular detail. Yet, until recently, the mutant huntingtin protein with its expanded polyglutamine domain has resisted structural study at the atomic level. We present here a review of recent developments in HD structural biology, facilitated by breakthrough data from solid-state NMR spectroscopy, electron microscopy, and complementary methods. The misfolded structures of the fibrillar proteins inform our mechanistic understanding of the disease-causing molecular processes in HD, other CAG repeat expansion disorders, and, more generally, protein deposition disease.

Huntington's disease: from pathology and genetics to potential therapies

2008 ◽  
Vol 412 (2) ◽  
pp. 191-209 ◽  
Author(s):  
Sara Imarisio ◽  
Jenny Carmichael ◽  
Viktor Korolchuk ◽  
Chien-Wen Chen ◽  
Shinji Saiki ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Trinucleotide Repeat ◽  
Mutant Protein ◽  
Mutant Huntingtin ◽  
Genetic Screens ◽  
Wild Type ◽  
Biological Studies ◽  
Polyglutamine Tract

Huntington's disease (HD) is a devastating autosomal dominant neurodegenerative disease caused by a CAG trinucleotide repeat expansion encoding an abnormally long polyglutamine tract in the huntingtin protein. Much has been learnt since the mutation was identified in 1993. We review the functions of wild-type huntingtin. Mutant huntingtin may cause toxicity via a range of different mechanisms. The primary consequence of the mutation is to confer a toxic gain of function on the mutant protein and this may be modified by certain normal activities that are impaired by the mutation. It is likely that the toxicity of mutant huntingtin is revealed after a series of cleavage events leading to the production of N-terminal huntingtin fragment(s) containing the expanded polyglutamine tract. Although aggregation of the mutant protein is a hallmark of the disease, the role of aggregation is complex and the arguments for protective roles of inclusions are discussed. Mutant huntingtin may mediate some of its toxicity in the nucleus by perturbing specific transcriptional pathways. HD may also inhibit mitochondrial function and proteasome activity. Importantly, not all of the effects of mutant huntingtin may be cell-autonomous, and it is possible that abnormalities in neighbouring neurons and glia may also have an impact on connected cells. It is likely that there is still much to learn about mutant huntingtin toxicity, and important insights have already come and may still come from chemical and genetic screens. Importantly, basic biological studies in HD have led to numerous potential therapeutic strategies.

scholarly journals A YAC Mouse Model for Huntington’s Disease with Full-Length Mutant Huntingtin, Cytoplasmic Toxicity, and Selective Striatal Neurodegeneration

Neuron ◽  
1999 ◽  
Vol 23 (1) ◽  
pp. 181-192 ◽  
Author(s):  
J.Graeme Hodgson ◽  
Nadia Agopyan ◽  
Claire-Anne Gutekunst ◽  
Blair R Leavitt ◽  
Fred LePiane ◽  
...  
Keyword(s):  
Mouse Model ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Full Length ◽  
Mutant Huntingtin

scholarly journals The huntingtin inclusion is a dynamic phase-separated compartment

2019 ◽  
Vol 2 (5) ◽  
pp. e201900489 ◽  
Author(s):  
Fahmida Aktar ◽  
Chakkapong Burudpakdee ◽  
Mercedes Polanco ◽  
Sen Pei ◽  
Theresa C Swayne ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Vacuolar Membrane ◽  
Mutant Huntingtin ◽  
Small Particles ◽  
Huntingtin Protein ◽  
Disordered Protein ◽  
Dynamic Phase ◽  
Mutant Huntingtin Protein ◽  
Polyglutamine Tract

Inclusions of disordered protein are a characteristic feature of most neurodegenerative diseases, including Huntington’s disease. Huntington’s disease is caused by expansion of a polyglutamine tract in the huntingtin protein; mutant huntingtin protein (mHtt) is unstable and accumulates in large intracellular inclusions both in affected individuals and when expressed in eukaryotic cells. Using mHtt-GFP expressed in Saccharomyces cerevisiae, we find that mHtt-GFP inclusions are dynamic, mobile, gel-like structures that concentrate mHtt together with the disaggregase Hsp104. Although inclusions may associate with the vacuolar membrane, the association is reversible and we find that inclusions of mHtt in S. cerevisiae are not taken up by the vacuole or other organelles. Instead, a pulse-chase study using photoconverted mHtt-mEos2 revealed that mHtt is directly and continuously removed from the inclusion body. In addition to mobile inclusions, we also imaged and tracked the movements of small particles of mHtt-GFP and determine that they move randomly. These observations suggest that inclusions may grow through the collision and coalescence of small aggregative particles.

scholarly journals Striatal Mutant Huntingtin Protein Levels Decline with Age in Homozygous Huntington’s Disease Knock-In Mouse Models

2018 ◽  
Vol 7 (2) ◽  
pp. 137-150 ◽  
Author(s):  
Nicholas R. Franich ◽  
Manuela Basso ◽  
Emily A. André ◽  
Joseph Ochaba ◽  
Amit Kumar ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Mouse Models ◽  
Mutant Huntingtin ◽  
Huntingtin Protein ◽  
Protein Levels ◽  
Mutant Huntingtin Protein

scholarly journals Treatment with JQ1, a BET bromodomain inhibitor, is selectively detrimental to R6/2 Huntington’s disease mice

2019 ◽  
Vol 29 (2) ◽  
pp. 202-215
Author(s):  
Amanda J Kedaigle ◽  
Jack C Reidling ◽  
Ryan G Lim ◽  
Miriam Adam ◽  
Jie Wu ◽  
...  
Keyword(s):  
Neurodegenerative Disease ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Motor Performance ◽  
Protein Translation ◽  
Epigenetic Alterations ◽  
Wild Type ◽  
Behavioral Phenotypes ◽  
High Molecular Weight Species ◽  
Mutant Huntingtin Protein

Abstract Transcriptional and epigenetic alterations occur early in Huntington’s disease (HD), and treatment with epigenetic modulators is beneficial in several HD animal models. The drug JQ1, which inhibits histone acetyl-lysine reader bromodomains, has shown promise for multiple cancers and neurodegenerative disease. We tested whether JQ1 could improve behavioral phenotypes in the R6/2 mouse model of HD and modulate HD-associated changes in transcription and epigenomics. R6/2 and non-transgenic (NT) mice were treated with JQ1 daily from 5 to 11 weeks of age and behavioral phenotypes evaluated over this period. Following the trial, cortex and striatum were isolated and subjected to mRNA-seq and ChIP-seq for the histone marks H3K4me3 and H3K27ac. Initially, JQ1 enhanced motor performance in NT mice. In R6/2 mice, however, JQ1 had no effect on rotarod or grip strength but exacerbated weight loss and worsened performance on the pole test. JQ1-induced gene expression changes in NT mice were distinct from those in R6/2 and primarily involved protein translation and bioenergetics pathways. Dysregulation of HD-related pathways in striatum was exacerbated by JQ1 in R6/2 mice, but not in NTs, and JQ1 caused a corresponding increase in the formation of a mutant huntingtin protein-dependent high molecular weight species associated with pathogenesis. This study suggests that drugs predicted to be beneficial based on their mode of action and effects in wild-type or in other neurodegenerative disease models may have an altered impact in the HD context. These observations have important implications in the development of epigenetic modulators as therapies for HD.

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