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bioRxiv · 10.1101/2021.10.04.462757

Proteasome-associated ubiquitin ligase relays target plant hormone-specific transcriptional activators

Wang, Z.·Orosa-Puente, B.·Nomoto, M.·Grey, H.·Potuschak, T.·Matsuura, T.·Mori, I. C.·Tada, Y.·Genschik, P.·Spoel, S. H.
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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 Arabidopsis 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 was regulated by sequential action of three ubiquitin ligases, including UPL3/4, while proteasome processing of EIN3 required physical handover between ethylene-responsive SCFEBF2 and UPL3/4 ligases. Consequently, UPL3/4 controlled extensive hormone-induced developmental and stress-responsive transcriptional programmes. 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. One-Sentence SummaryTranscriptional activators are targeted by proteasomal ubiquitin ligase relays that control their activity and stability.

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Wang, Z., Orosa-Puente, B., Nomoto, M., Grey, H., Potuschak, T., Matsuura, T., Mori, I. C., Tada, Y., Genschik, P., Spoel, S. H.. 2021-10-05. Proteasome-associated ubiquitin ligase relays target plant hormone-specific transcriptional activators. https://doi.org/10.1101/2021.10.04.462757

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