PXD039183

PXD039183 is an original dataset announced via ProteomeXchange.

Title	The autophagy receptor NBR1 directs the clearance of photodamaged chloroplasts
Description	The ubiquitin-binding NBR1 autophagy receptor plays a prominent role in recognizing ubiquitylated protein aggregates for vacuolar degradation during macroautophagy. Here, we show that upon exposing Arabidopsis plants to intense light, NBR1 associates with photodamaged chloroplasts independently of ATG7, a core component of the canonical autophagy machinery. NBR1 coats both the surface and interior of chloroplasts which is then followed by direct engulfment of the organelle into the central vacuole via a microautophagy-type process. The relocalization of NBR1 into chloroplasts does not require the chloroplast translocon complexes embedded in the envelope but is instead greatly enhanced by removing the self-oligomerization mPB1 domain of NBR1. The delivery of NBR1-decorated chloroplasts into vacuoles depends on the ubiquitin-binding UBA2 domain of NBR1 but is independent of the E3 ligases SP1 and PUB4, known to direct the ubiquitylation of chloroplast surface proteins. Compared to wild type plants, nbr1 mutants have altered levels of a subset of chloroplast proteins and display abnormal chloroplast density and sizes upon high light exposure. We postulate that, as photodamaged chloroplasts lose envelope integrity, cytosolic ligases reach the chloroplast interior to ubiquitylate thylakoid and stroma proteins which are then recognize by NBR1 for autophagic clearance. This study uncovers a new function of NBR1 in the degradation of damaged chloroplasts by microautophagy.
HostingRepository	PRIDE
AnnounceDate	2023-01-16
AnnouncementXML	Submission_2023-01-16_11:04:10.354.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Kuo-EnChen
SpeciesList	scientific name: Arabidopsis thaliana (Mouse-ear cress); NCBI TaxID: 3702;
ModificationList	carbamoylated residue; acetylated residue
Instrument	Q Exactive HF

Revision	Datetime	Status	ChangeLog Entry
0	2023-01-02 19:12:40	ID requested
⏵ 1	2023-01-16 11:04:10	announced

Dataset with its publication pending

submitter keyword: microautophagy, ubiquitin.,NBR1, chlorophagy

Richard D.Vierstra
contact affiliation	Biology department, Washington University in Saint Louis, Saint Louis, MO, USA
contact email	rdvierstra@wustl.edu
lab head
Kuo-EnChen
contact affiliation	Department of Biology, Washington University in St. Louis
contact email	kuo-en@wustl.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD039183
     1. Label: PRIDE project
     2. Name: The autophagy receptor NBR1 directs the clearance of photodamaged chloroplasts