PXD035040

PXD035040 is an original dataset announced via ProteomeXchange.

Title	APEX2-proximity labelling of small heat shock protein condensates and aggregates
Description	Small heat shock proteins are chaperones that are essential in preserving the integrity of the cellular proteome during stress conditions. The human genome encodes ten small heat shock proteins (HspB1-HspB10), which often form polydisperse multimeric functional structures. Uniquely, HspB2 and HspB3 form a tetrameric complex with a well-defined 3:1 subunit ratio, suggesting that precise control of their expression is crucial for their function as chaperones. Indeed, disruption of the HspB2-HspB3 interaction and stoichiometry has been linked to myopathic disorders. To gain insight in the molecular mechanisms involved in such disorders, we studied the intracellular behavior of HspB2 and HspB3 at varying ratios. In this study, we show that expression of HspB2 alone results in the formation of liquid nuclear condensates, while co-expression of a small amount of HspB3 results in a diffuse distribution of HspB2 in the nucleus. In contrast, co-expression of HspB3 in equimolar amounts to HspB2 resulted in the formation of large aggregates in both the cytoplasm and the nucleus. The condensates as well as the aggregates can be dissolved by shifting the HspB2:HspB3 balance, indicating that these structures are reversible and able to dynamically exchange biomolecules with the environment. Both condensates and aggregates are expected to interact with, and potentially trap specific sets of proteins, which may be linked to associated pathologies. To identify these proteins and elucidate the composition of HspB2 condensates and aggregates, we performed proximity labelling using an engineered ascorbate peroxidase (APEX). We found a striking enrichment of disordered proteins in HspB2:HspB3 containing aggregates, as well as multiple autophagy factors, indicating that the cell is actively attempting to clear these aggregates. In contrast, very few proteins were specifically enriched in condensates, suggesting that most proteins interact only weakly and transiently with the liquid condensates.
HostingRepository	PRIDE
AnnounceDate	2022-09-20
AnnouncementXML	Submission_2022-09-20_00:22:35.595.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Pascal Jansen
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	acetylated residue; monohydroxylated residue; iodoacetamide derivatized residue
Instrument	Orbitrap Exploris 480

Revision	Datetime	Status	ChangeLog Entry
0	2022-06-30 07:29:47	ID requested
⏵ 1	2022-09-20 00:22:35	announced

Dataset with its publication pending

submitter keyword: Human, small heat shock protein, HspB2, HspB5, liquid-liquid phase separation, protein aggregation, APEX2, proximity labelling, HEK293T cells

Evan Spruijt
contact affiliation	Physical Organic Chemistry, Radboud University, Nijmegen, the Netherlands
contact email	evan.spruijt@ru.nl
lab head
Pascal Jansen
contact affiliation	Radboud University
contact email	p.jansen@science.ru.nl
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD035040
     1. Label: PRIDE project
     2. Name: APEX2-proximity labelling of small heat shock protein condensates and aggregates