Back to Search Start Over

SINAT E3 Ubiquitin Ligases Mediate FREE1 and VPS23A Degradation to Modulate Abscisic Acid Signaling.

Authors :
Xia FN
Zeng B
Liu HS
Qi H
Xie LJ
Yu LJ
Chen QF
Li JF
Chen YQ
Jiang L
Xiao S
Source :
The Plant cell [Plant Cell] 2020 Oct; Vol. 32 (10), pp. 3290-3310. Date of Electronic Publication: 2020 Aug 04.
Publication Year :
2020

Abstract

In plants, the ubiquitin-proteasome system, endosomal sorting, and autophagy are essential for protein degradation; however, their interplay remains poorly understood. Here, we show that four Arabidopsis ( Arabidopsis thaliana ) E3 ubiquitin ligases, SEVEN IN ABSENTIA OF ARABIDOPSIS THALIANA 1 (SINAT1), SINAT2, SINAT3, and SINAT4, regulate the stabilities of FYVE DOMAIN PROTEIN REQUIRED FOR ENDOSOMAL SORTING1 (FREE1) and VACUOLAR PROTEIN SORTING23A (VPS23A), key components of the endosomal sorting complex required for transport-I, to modulate abscisic acid (ABA) signaling. GFP-SINAT1, GFP-SINAT2, and GFP-SINAT4 primarily localized to the endosomal and autophagic vesicles. SINATs controlled FREE1 and VPS23A ubiquitination and proteasomal degradation. SINAT overexpressors showed increased ABA sensitivity, ABA-responsive gene expression, and PYRABACTIN RESISTANCE1-LIKE4 protein levels. Furthermore, the SINAT-FREE1/VPS23A proteins were codegraded by the vacuolar pathway. In particular, during recovery post-ABA exposure, SINATs formed homo- and hetero-oligomers in vivo, which were disrupted by the autophagy machinery. Taken together, our findings reveal a novel mechanism by which the proteasomal and vacuolar turnover systems regulate ABA signaling in plants.<br /> (© 2020 American Society of Plant Biologists. All rights reserved.)

Details

Language :
English
ISSN :
1532-298X
Volume :
32
Issue :
10
Database :
MEDLINE
Journal :
The Plant cell
Publication Type :
Academic Journal
Accession number :
32753431
Full Text :
https://doi.org/10.1105/tpc.20.00267