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

Abstract

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.

• Authors: Karen A Sap, Arzu Tugce Guler, Aleksandra Bury, Dick Dekkers, Jeroen A A Demmers, Eric A Reits
• Journal: Journal of Huntington's disease (J Huntingtons Dis) Vol. 10 Issue 3 Pg. 335-347 ( 2021) ISSN: 1879-6400 [Electronic] Netherlands
• PMID: 34151850 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Htt protein, mouse
• Huntingtin Protein
• Mutant Proteins
• Nerve Tissue Proteins
• Synaptotagmin I
• Syt1 protein, mouse

Topics

• Animals
• Brain (metabolism)
• Chromatography, Liquid
• Huntingtin Protein (genetics, metabolism)
• Huntington Disease (genetics)
• Immunoprecipitation
• Mice
• Mutant Proteins (metabolism)
• Nerve Tissue Proteins (genetics, metabolism)
• Synaptotagmin I
• Tandem Mass Spectrometry