title: NINJA connects the co-repressor TOPLESS to jasmonate signalling.
abstract: Jasmonoyl-isoleucine (JA-Ile) is a plant hormone that regulates a broad array of plant defence and developmental processes. JA-Ile-responsive gene expression is regulated by the transcriptional activator MYC2 that interacts physically with the jasmonate ZIM-domain (JAZ) repressor proteins. On perception of JA-Ile, JAZ proteins are degraded and JA-Ile-dependent gene expression is activated. The molecular mechanisms by which JAZ proteins repress gene expression remain unknown. Here we show that the Arabidopsis JAZ proteins recruit the Groucho/Tup1-type co-repressor TOPLESS (TPL) and TPL-related proteins (TPRs) through a previously uncharacterized adaptor protein, designated Novel Interactor of JAZ (NINJA). NINJA acts as a transcriptional repressor whose activity is mediated by a functional TPL-binding EAR repression motif. Accordingly, both NINJA and TPL proteins function as negative regulators of jasmonate responses. Our results point to TPL proteins as general co-repressors that affect multiple signalling pathways through the interaction with specific adaptor proteins. This new insight reveals how stress-related and growth-related signalling cascades use common molecular mechanisms to regulate gene expression in plants.
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Technologiepark 927, B-9052 Gent, Belgium.
authors.forename: Laurens
authors.initials: L
authors.lastname: Pauwels
authors.forename: Gemma Fernández
authors.initials: GF
authors.lastname: Barbero
authors.forename: Jan
authors.initials: J
authors.lastname: Geerinck
authors.forename: Sofie
authors.initials: S
authors.lastname: Tilleman
authors.forename: Wim
authors.initials: W
authors.lastname: Grunewald
authors.forename: Amparo Cuéllar
authors.initials: AC
authors.lastname: Pérez
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Chico
authors.forename: Robin Vanden
authors.initials: RV
authors.lastname: Bossche
authors.forename: Jared
authors.initials: J
authors.lastname: Sewell
authors.forename: Eduardo
authors.initials: E
authors.lastname: Gil
authors.forename: Gloria
authors.initials: G
authors.lastname: García-Casado
authors.forename: Erwin
authors.initials: E
authors.lastname: Witters
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
authors.forename: Jeff A
authors.initials: JA
authors.lastname: Long
authors.forename: Geert
authors.initials: G
authors.lastname: De Jaeger
authors.forename: Roberto
authors.initials: R
authors.lastname: Solano
authors.forename: Alain
authors.initials: A
authors.lastname: Goossens
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D008954:Models, Biological; D054883:Oxylipins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D030821:Plants, Genetically Modified; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D012097:Repressor Proteins; C549252:NINJA protein, Arabidopsis; C511291:At1g15750 protein, Arabidopsis; C011006:jasmonic acid