N-alpha-acetylation of Huntingtin protein increases its propensity to aggregate

Leah Gottlieb,Lin Guo,James Shorter,Ronen Marmorstein

doi:10.1016/j.jbc.2021.101363

Leah Gottlieb, Lin Guo + Show 2 more

Open Access

https://doi.org/10.1016/j.jbc.2021.101363

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Abstract

Huntington’s disease (HD) is a neurodegenerative disorder caused by a poly-CAG expansion in the first exon of the HTT gene, resulting in an extended poly-glutamine tract in the N-terminal domain of the Huntingtin (Htt) protein product. Proteolytic fragments of the poly-glutamine–containing N-terminal domain form intranuclear aggregates that are correlated with HD. Post-translational modification of Htt has been shown to alter its function and aggregation properties. However, the effect of N-terminal Htt acetylation has not yet been considered. Here, we developed a bacterial system to produce unmodified or N-terminally acetylated and aggregation-inducible Htt protein. We used this system together with biochemical, biophysical, and imaging studies to confirm that the Htt N-terminus is an in vitro substrate for the NatA N-terminal acetyltransferase and show that N-terminal acetylation promotes aggregation. These studies represent the first link between N-terminal acetylation and the promotion of a neurodegenerative disease and implicates NatA-mediated Htt acetylation as a new potential therapeutic target in HD.

Highlights

Expansions longer than 35 are penetrant terminal domain of the Huntingtin (Htt) with a direct relationship between protein product
Numerous involuntary movements, and psychiatric studies have been conducted using a disturbances, which is accompanied by minimal N-terminal fragment construct neuronal degeneration in the striatum containing the 17-residue N-terminal domain (N17), a polyQ repeat (Qn), and, seven N-terminal acetyltransferase (NAT) (NatA-F and H) have been in some cases, the C-terminal polyproline identified in humans, each consisting of a (PolyP) sequence to shed light on the catalytic subunit
To directly interrogate the involvement of the Huntingtin (Htt) Nterminus in Htt aggregation, we developed an aggregation-inducible recombinant N-terminal Htt protein system (Fig. 1A)

Summary

INTRODUCTION

Nucleus and, in the fatal autosomal neurodegenerative characteristic neuronal intranuclear disease caused by a poly-CAG inclusion bodies [17,18]. With ~80% of the human protein recently, it was confirmed both wild-type being N-terminally acetylated, this coand mutant Htt produced in HEK293 cells and post-translational modification has are N-terminally processed to yield an broad implications in the regulation of acetylated N-terminus: Ac-ATLEK-, cellular processes, human development which purified as a dimer and was able to and disease [48,49]. In mark has been demonstrated to addition, mouse brain has been reported influence protein-protein interactions, to have N-terminally acetylated Htt protein-membrane interactions, and protein [57] Based on these earlier studies, we (Reviewed in 50). Assess human NatA and NatA/HYPK terminal acetylation promotes Htt protein complex activity towards a series of aggregation, which has implications for synthetic peptides, including one with the adverse roles in neurodegenerative first 7 residues of Htt after methionine.

RESULTS

DISCUSSION

EXPERIMENTAL PROCEDURES