NINJA connects the co-repressor TOPLESS to jasmonate signalling.
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.
Pauwels
Laurens
L
Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Technologiepark 927, B-9052 Gent, Belgium.
Barbero
Gemma Fernández
GF
Geerinck
Jan
J
Tilleman
Sofie
S
Grunewald
Wim
W
Pérez
Amparo Cuéllar
AC
Chico
José Manuel
JM
Bossche
Robin Vanden
RV
Sewell
Jared
J
Gil
Eduardo
E
García-Casado
Gloria
G
Witters
Erwin
E
Inzé
Dirk
D
Long
Jeff A
JA
De Jaeger
Geert
G
Solano
Roberto
R
Goossens
Alain
A
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
D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D012097:Repressor Proteins; C549252:NINJA protein, Arabidopsis; C511291:At1g15750 protein, Arabidopsis; C011006:jasmonic acid