Figure 3.

JAZ proteins repress JA signaling. (A) JAZ proteins interact with bHLH-type TFs, such as MYC2/3/4, mediated by direct binding between the Jas and JAZ-interacting domain (JID) domains, respectively. The ZIM domain of most JAZ proteins can interact with the adapter protein Novel Interactor of JAZ (NINJA). Through an ERF-associated amphiphilic repression (EAR) motif, NINJA is capable of recruiting the co-repressor TOPLESS (TPL) to the complex. (B) The ZIM domains of some JAZ proteins, such as JAZ8 and JAZ13, are unable to bind NINJA, but these JAZ proteins contain an EAR motif themselves. (C) Alternative splicing of certain JAZ transcripts leads to truncated JAZ proteins lacking part of the Jas domain. In the case of JAZ10.4, an N-terminal cryptic MYC2-binding domain (CMID) mediates interaction with bHLH-type TFs such as MYC2/3/4. Both JAZ8/13 and JAZ10.4 have deviating Jas domains and do not associate with SCF^COI1 in a JA-Ile dependent way. (D) The interaction of JAZ proteins with MYC2 is mediated by both the JID and the transcriptional activation domain (TAD). This interaction competes with the binding of this surface with the co-activating mediator subunit MED25. Figure partially adapted from Pauwels and Goossens [60].