Cross-regulatory mechanisms in hormone signaling

Kuppusamy, Kavitha T.; Walcher, Cristina L.; Nemhauser, Jennifer L.

doi:10.1007/s11103-008-9389-2

Cited by 69 publications

(45 citation statements)

References 55 publications

(75 reference statements)

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“…This is likely to be the result of effects on brassinosteroid biosynthesis, as the brx phenotype and impaired DR5::GUS expression can be significantly rescued by exogenous application of this class of phytohormones . These findings are part of accumulating evidence for a rate-limiting role of the brassinosteroid pathway in the auxin response (Hardtke, 2007;Kuppusamy et al, 2008;Nemhauser et al, 2004;Vert et al, 2008). Interestingly, expression of BRX is itself strongly induced by auxin .…”

Section: Introductionmentioning

confidence: 68%

Dynamic, auxin-responsive plasma membrane-to-nucleus movement ofArabidopsisBRX

et al. 2009

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In Arabidopsis, interplay between nuclear auxin perception and trans-cellular polar auxin transport determines the transcriptional auxin response. In brevis radix (brx) mutants, this response is impaired, probably indirectly because of disturbed crosstalk between the auxin and brassinosteroid pathways. Here we provide evidence that BRX protein is plasma membrane-associated, but translocates to the nucleus upon auxin treatment to modulate cellular growth, possibly in conjunction with NGATHA class B3 domain-type transcription factors. Application of the polar auxin transport inhibitor naphthalene phthalamic acid (NPA) resulted in increased BRX abundance at the plasma membrane. Thus, nuclear translocation of BRX could depend on cellular auxin concentration or on auxin flux. Supporting this idea, NPA treatment of wild-type roots phenocopied the brx root meristem phenotype. Moreover, BRX is constitutively turned over by the proteasome pathway in the nucleus. However, a stabilized C-terminal BRX fragment significantly rescued the brx root growth phenotype and triggered a hypocotyl gain-of-function phenotype, similar to strong overexpressors of full length BRX. Therefore, although BRX activity is required in the nucleus, excess activity interferes with normal development. Finally, similar to the PIN-FORMED 1 (PIN1) auxin efflux carrier, BRX is polarly localized in vascular cells and subject to endocytic recycling. Expression of BRX under control of the PIN1 promoter fully rescued the brx short root phenotype, suggesting that the two genes act in the same tissues. Collectively, our results suggest that BRX might provide a contextual readout to synchronize cellular growth with the auxin concentration gradient across the root tip.

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Section: Introductionmentioning

confidence: 68%

Dynamic, auxin-responsive plasma membrane-to-nucleus movement ofArabidopsisBRX

et al. 2009

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“…19 Notably, many of the phytohormones are coordinated with other phytohormones in their effects on plant development, and have multiple cross-talk junctions between them, forming a complex network of coordinated effects (reviewed in ref. 66). .…”

Section: Other Phytohormones and Plant Responses To Environmental Cuesmentioning

confidence: 99%

Strigolactones as mediators of plant growth responses to environmental conditions

Koltai¹,

Kapulnik²

2011

psb

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“…Ultimately, through crosstalk with other hormonal pathways, such as of auxins, gibberellins (GAs), abscisic acid (ABA), ethylene (ET), and salicylic acid, JAs are (in)directly involved in the fine-tuning of a myriad of plant cellular processes. This multifaceted role of JAs has been covered by excellent reviews (Wasternack, 2007;Balbi and Devoto, 2008;Kazan and Manners, 2008;Bari and Jones, 2009;Browse, 2009a;Grant and Jones, 2009;Kuppusamy et al, 2009;Pauwels et al, 2009;Reinbothe et al, 2009;Hoffmann et al, 2011;Robert-Seilaniantz et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

The JAZ Proteins: A Crucial Interface in the Jasmonate Signaling Cascade

2011

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Jasmonates are phytohormones that regulate many aspects of plant growth, development, and defense. Within the signaling cascades that are triggered by jasmonates, the JASMONATE-ZIM DOMAIN (JAZ) repressor proteins play a central role. The endogenous bioactive JA-Ile conjugate mediates the binding of JAZ proteins to the F-box protein CORONATINE INSENSITIVE1 (COI1), part of the Skp1/Cullin/F-box SCF COI1 ubiquitin E3 ligase complex. Upon the subsequent destruction of the JAZ proteins by the 26S proteasome, multiple transcription factors are relieved from JAZ-mediated repression, allowing them to activate their respective downstream responses. However, many questions remain regarding the targets, specificity, function, and regulation of the different JAZ proteins. Here, we review recent studies on the model plant Arabidopsis thaliana that provided essential and novel insights. JAZ proteins have been demonstrated to interact with a broad array of transcription factors that each control specific downstream processes. Recruitment of the corepressor TOPLESS unveiled a mechanism for JAZ-mediated gene repression. Finally, the presence of JAZ proteins was also found to be regulated by alternative splicing and interactions with proteins from other hormonal signaling pathways. Overall, these contemporary findings underscore the value of protein-protein interaction studies to acquire fundamental insight into molecular signaling pathways.

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Cross-regulatory mechanisms in hormone signaling

Cited by 69 publications

References 55 publications

Dynamic, auxin-responsive plasma membrane-to-nucleus movement ofArabidopsisBRX

Dynamic, auxin-responsive plasma membrane-to-nucleus movement ofArabidopsisBRX

Strigolactones as mediators of plant growth responses to environmental conditions

The JAZ Proteins: A Crucial Interface in the Jasmonate Signaling Cascade

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