PXD053954-2

PXD053954 is an original dataset announced via ProteomeXchange.

Title	Huntingtin contains a ubiquitin-binding domain and regulates lysosomal targeting of mitochondrial and RNA-binding proteins
Description	Understanding the normal function of the Huntingtin (HTT) protein is of significance in the design and implementation of therapeutic strategies for Huntington’s disease (HD). Expansion of the CAG repeat in the HTT gene, encoding an expanded polyglutamine (polyQ) repeat within the HTT protein, causes HD and may compromise HTT’s normal activity contributing to HD pathology. Here, we investigated the previously defined role of HTT in autophagy specifically through studying HTT’s association with ubiquitin. We find that HTT interacts directly with ubiquitin in vitro. Tandem affinity purification was used to identify ubiquitinated and ubiquitin-associated proteins that co-purify with a HTT N-terminal fragment under basal conditions. Co-purification is enhanced by HTT polyQ expansion and reduced by mimicking HTT serine 421 phosphorylation. The identified HTT-interacting proteins include RNA-binding proteins (RBPs) involved in mRNA translation, proteins enriched in stress granules, the nuclear proteome, the defective ribosomal products (DRiPs) proteome and the brain-derived autophagosomal proteome. To determine whether the proteins interacting with HTT are autophagic targets, HTT knockout (KO) cells and immunoprecipitation of lysosomes were used to investigate autophagy in the absence of HTT. HTT KO was associated with reduced abundance of mitochondrial proteins in the lysosome, indicating a potential compromise in basal mitophagy, and increased lysosomal abundance of RBPs which may result from compensatory upregulation of starvation-induced macroautophagy. We suggest HTT is critical for appropriate basal clearance of mitochondrial proteins and RBPs, hence reduced HTT proteostatic function with mutation may contribute to the neuropathology of HD.
HostingRepository	PRIDE
AnnounceDate	2024-10-22
AnnouncementXML	Submission_2024-10-22_06:51:51.492.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Joao Paulo
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	TMT6plex-126 reporter+balance reagent acylated residue
Instrument	Orbitrap Fusion

Revision	Datetime	Status	ChangeLog Entry
0	2024-07-15 09:28:44	ID requested
1	2024-07-30 10:17:10	announced
⏵ 2	2024-10-22 06:51:51	announced	2024-10-22: Updated project metadata.

10.1073/PNAS.2319091121;

submitter keyword: mitophagy,Huntington’s Disease, selective autophagy, RNA-binding proteins, Huntingtin, Ubiquitin-binding domain

Joan S. Steffan
contact affiliation	Department of Psychiatry and Human Behavior University of California Irvine 4056 Gross Hall/ Stem Cell Research Center 845 Health Sciences Road Irvine, CA 92697-1705
contact email	jssteffa@uci.edu
lab head
Joao Paulo
contact affiliation	Harvard Medical School
contact email	joao_paulo@post.harvard.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD053954
     1. Label: PRIDE project
     2. Name: Huntingtin contains a ubiquitin-binding domain and regulates lysosomal targeting of mitochondrial and RNA-binding proteins