PT  - JOURNAL ARTICLE
AU  - Chao Luo
AU  - Xiao-Teng Cai
AU  - Jin Du
AU  - Tao-Lan Zhao
AU  - Peng-Fei Wang
AU  - Ping-Xia Zhao
AU  - Rui Liu
AU  - Qi Xie
AU  - Xiao-Feng Cao
AU  - Cheng-Bin Xiang
TI  - PARAQUAT TOLERANCE3 is an E3 ligase and acts as a negative regulator of oxidative stress response
AID  - 10.1101/040543
DP  - 2016 Jan 01
TA  - bioRxiv
PG  - 040543
4099  - http://biorxiv.org/content/early/2016/02/22/040543.short
4100  - http://biorxiv.org/content/early/2016/02/22/040543.full
AB  - Oxidative damage could be caused in plant cells when biotic and abiotic stresses are imposed. While the response to oxidative stress is well studied, little is known about how the activated response is switched off when oxidative stress is diminished. By studying Arabidopsis mutant paraquat tolerance3, we identified the genetic locus PARAQUAT TOLERANCE3 (PQT3) as a major negative regulator of oxidative stress tolerance. PQT3, encoding an E3 ligase, is rapidly down-regulated by oxidative stress. PQT3 has E3 ubiquitin ligase activity in ubiquitination assay. Subsequently, we identified PRMT4b as a PQT3-interacting protein. By histone methylation, PRMT4b may regulate the expression of APX1 and GPX1, encoding two key enzymes against oxidative stress. Moreover, PQT3 is able to recognize PRMT4b for targeted degradation via 26S proteasome. Therefore, we have identified PQT3 as an E3 ligase that acts as a negative regulator of activated response to oxidative stress.