Social Network: JAZ Protein Interactions Expand Our Knowledge of Jasmonate Signaling

Amanda Wager,John Browse

doi:10.3389/fpls.2012.00041

Abstract

Members of the family of JASMONATE ZIM-DOMAIN (JAZ) proteins are key regulators of the jasmonate (JA) hormonal response. The 12-member family is characterized by three conserved domains, an N-terminal domain, a TIFY-containing ZINC-FINGER EXPRESSED IN INFLORESCENCE MERISTEM domain, and a C-terminal Jas domain. JAZ proteins regulate JA-responsive gene transcription by inhibiting DNA-binding transcription factors in the absence of JA. JAZ proteins interact in a hormone-dependent manner with CORONATINE INSENSITIVE 1 (COI1), the recognition component of the E3 ubiquitin ligase, SCFCOI1, resulting in the ubiquitination and subsequent degradation of JAZs via the 26S proteasome pathway. Since their discovery in 2007, JAZ proteins have been implicated in protein–protein interactions with multiple transcription factors. These studies have shed light on the mechanism by which JAZs repress transcription, are targeted for degradation, modulate the JA signaling response, and participate in crosstalk with other hormone signaling pathways. In this review, we will take a close look at the recent discoveries made possible by the characterization JAZ protein–protein interactions.

Highlights

Ellis Marsalis, primum mobile of the diverse and influential jazz family, knows that the interactions and connections made by family members provide insight into the operation and purpose of an extended social network
This work showed that degradation of JASMONATE ZINC-FINGER EXPRESSED IN INFLORESCENCE MERISTEM (ZIM)-DOMAIN (JAZ) proteins is essential for induction of JA-mediated responses, an action that is dependent on the F-box protein CORONATINE INSENSITIVE 1 (COI1) and the 26S proteasome (Mandaokar et al, 2006; Chini et al, 2007; Thines et al, 2007; Yan et al, 2007). These findings provided the basis for the current model for JA signaling in which JA–Ile serves as a signal that activates transcription of JA responsive genes by enhancing interaction between JAZ repressor proteins and COI1, the recognition component of the SCFCOI1 E3 ligase (Devoto et al, 2002; Staswick et al, 2002; Melotto et al, 2008)
Additional yeast-two-hybrid assays using truncated JAZ1 identified a C-terminally truncated JAZ1 peptide capable of HISTONE DEACETYLASE 6 (HDA6) interaction and an N-terminally truncated peptide that is not. These results indicate that interaction with HDA6 is likely mediated by residues within the NT or ZIM domain of JAZ1, but additional experiments will be required to identify precise regions of JAZ proteins that are important for interaction with HDA6 (Zhu et al, 2011)

Summary

Amanda Wager and John Browse*

JAZ proteins interact in a hormone-dependent manner with CORONATINE INSENSITIVE 1 (COI1), the recognition component of the E3 ubiquitin ligase, SCFCOI1, resulting in the ubiquitination and subsequent degradation of JAZs via the 26S proteasome pathway. Since their discovery in 2007, JAZ proteins have been implicated in protein–protein interactions with multiple transcription factors. These studies have shed light on the mechanism by which JAZs repress transcription, are targeted for degradation, modulate the JA signaling response, and participate in crosstalk with other hormone signaling pathways.

INTRODUCTION

Wager and Browse

In vivo relevance