PXD018717-1

PXD018717 is an original dataset announced via ProteomeXchange.

Title	An evolutionarily distinct chaperone is required for 20S proteasome α-ring assembly in Arabidopsis
Description	26S proteasomes direct the degradation of many short-lived regulatory proteins and dysfunctional polypeptides, and thus are essential effectors of eukaryotic proteostasis. Proteolysis by this multi-subunit complex occurs inside a barrel-shaped 20S core protease (CP) whose quaternary structure is conserved across all domains of life, and comprises four co-axially stacked heptameric rings formed by structurally related α- and β-subunits in an αββα configuration. CP biogenesis typically begins with the assembly of the α-rings, which then serve as templates for β-subunit integration, three of which present a peptidase active site within the central β-ring chamber. In eukaryotes, α-ring assembly is partially mediated by two hetero-dimeric chaperones, termed Pba1-Pba2 and Pba3-Pba4 in yeast (or PAC1-PAC2 and PAC3-PAC4 in mammals). Pba1-Pba2 initially promotes orderly recruitment of the α-subunits through interactions between their C-terminal HbYX/HbF motifs and shallow pockets at the α5-α6 and α6-α7 interfaces. Here, we identify PBAC5 as a fifth α-ring assembly chaperone in Arabidopsis that directly associates with the Pba1 homolog PBAC1 to form a trimeric PBAC5-PBAC1-PBAC2 complex that can functionally replace the yeast Pba1-Pba2 pair. PBAC5 contains a HbYX motif that likely docks with the pocket formed between the α4 and α5 subunits during α-ring formation. Arabidopsis missing PBAC5, PBAC1, and/or PBAC2 are hypersensitive to proteotoxic, salt and osmotic stress, and display proteasome assembly defects, consistent with a role in CP assembly. Remarkably, while PBAC5 is evolutionarily conserved in plants, it is also present in other kingdoms, with homologs evident in a limited array of fungal, metazoan, and oomycete species.
HostingRepository	PRIDE
AnnounceDate	2020-05-18
AnnouncementXML	Submission_2020-05-18_05:24:12.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Fionn McLoughlin
SpeciesList	scientific name: Arabidopsis thaliana (Mouse-ear cress); NCBI TaxID: 3702;
ModificationList	acetylated residue; monohydroxylated residue; iodoacetamide derivatized residue
Instrument	Q Exactive

Revision	Datetime	Status	ChangeLog Entry
0	2020-04-21 09:05:29	ID requested
⏵ 1	2020-05-18 05:24:12	announced

Dataset with its publication pending

submitter keyword: Proteasome assembly, Arabidopsis

Richard David Vierstra
contact affiliation	Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
contact email	rdvierstra@wustl.edu
lab head
Fionn McLoughlin
contact affiliation	Washington University in Saint Louis
contact email	fmcloughlin@wustl.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD018717
     1. Label: PRIDE project
     2. Name: An evolutionarily distinct chaperone is required for 20S proteasome α-ring assembly in Arabidopsis