Proteasome-associated ubiquitin ligase relays target plant hormone-specific transcriptional activators.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36269824.
- Also identified by DOI 10.1126/sciadv.abn4466 and PMC identifier 9586472.
- Licence recorded as CC BY-NC.
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Abstract
The ubiquitin-proteasome system is vital to hormone-mediated developmental and stress responses in plants. Ubiquitin ligases target hormone-specific transcriptional activators (TAs) for degradation, but how TAs are processed by proteasomes remains unknown. We report that in <i>Arabidopsis</i>, the salicylic acid- and ethylene-responsive TAs, NPR1 and EIN3, are relayed from pathway-specific ubiquitin ligases to proteasome-associated HECT-type UPL3/4 ligases. Activity and stability of NPR1 were regulated by sequential action of three ubiquitin ligases, including UPL3/4, while proteasome processing of EIN3 required physical handover between ethylene-responsive SCF<sup>EBF2</sup> and UPL3/4 ligases. Consequently, UPL3/4 controlled extensive hormone-induced developmental and stress-responsive transcriptional programs. Thus, our findings identify unknown ubiquitin ligase relays that terminate with proteasome-associated HECT-type ligases, which may be a universal mechanism for processive degradation of proteasome-targeted TAs and other substrates.