BRI1 is a critical component of a plasma-membrane receptor for plant steroids

Wang, Wenfei; Seto, Hideharu; Fujioka, Shozo; Yoshida, Shigeo; Chory, Joanne

doi:10.1038/35066597

Cited by 741 publications

(607 citation statements)

References 23 publications

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“…Overexpression of JAW1, which is involved in the regulation of jasmonate biosynthesis (Palatnik et al, 2003;Schommer et al, 2008), leads to the enlargement of only the first rosette leaves, and these have a characteristic uneven shape. Leaf enlargement is also restricted to the first few rosette leaves in lines overexpressing GRF5 and BRI1, a brassinosteroid receptor (Wang et al, 2001;Horiguchi et al, 2005), whereas overexpression of GA20OX1, an enzyme involved in GA synthesis (Huang et al, 1998), yields enlarged young but not older leaves.…”

Section: Discussionmentioning

confidence: 99%

The Sink-Specific Plastidic Phosphate Transporter PHT4;2 Influences Starch Accumulation and Leaf Size in Arabidopsis

et al. 2011

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Nonphotosynthetic plastids are important sites for the biosynthesis of starch, fatty acids, and amino acids. The uptake and subsequent use of cytosolic ATP to fuel these and other anabolic processes would lead to the accumulation of inorganic phosphate (Pi) if not balanced by a Pi export activity. However, the identity of the transporter(s) responsible for Pi export is unclear. The plastid-localized Pi transporter PHT4;2 of Arabidopsis (Arabidopsis thaliana) is expressed in multiple sink organs but is nearly restricted to roots during vegetative growth. We identified and used pht4;2 null mutants to confirm that PHT4;2 contributes to Pi transport in isolated root plastids. Starch accumulation was limited in pht4;2 roots, which is consistent with the inhibition of starch synthesis by excess Pi as a result of a defect in Pi export. Reduced starch accumulation in leaves and altered expression patterns for starch synthesis genes and other plastid transporter genes suggest metabolic adaptation to the defect in roots. Moreover, pht4;2 rosettes, but not roots, were significantly larger than those of the wild type, with 40% greater leaf area and twice the biomass when plants were grown with a short (8-h) photoperiod. Increased cell proliferation accounted for the larger leaf size and biomass, as no changes were detected in mature cell size, specific leaf area, or relative photosynthetic electron transport activity. These data suggest novel signaling between roots and leaves that contributes to the regulation of leaf size.

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Section: Discussionmentioning

confidence: 99%

The Sink-Specific Plastidic Phosphate Transporter PHT4;2 Influences Starch Accumulation and Leaf Size in Arabidopsis

et al. 2011

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“…First, when the extracellular LRR and transmembrane domains of BRI1 were fused to the serine/threonine kinase domain of Xa21, a rice LRR receptor kinase for disease resistance, the chimeric receptor was able to elicit defense responses in rice cells upon treatment with BL [14]. Secondly, BRI1 was co-immunoprecipitated with the BR-binding activity and BR treatment was shown to induce BRI1 autophosphorylation, which indicates that BR interacts with BRI1 and activates its kinase activity [15]. However, these studies failed to demonstrate direct binding of BR to BRI1.…”

Section: Steroid Signaling In Plants 428mentioning

confidence: 99%

“…BR binding activates the BRI1 kinase and causes autophosphorylation of BRI1, as demonstrated by both mobility shift of BRI1 in SDS-PAGE and by increased signal detected by anti-phospho-serine/threonine antibodies in BR treated samples [15,21]. Many phosphorylation sites of BRI1 have recently been identified by mass spectrometry analysis of recombinant BRI1 expressed in E. coli or BRI1 immunoprecipitated from plant extracts [21,22].…”

Section: Br Activation Of Bri1 and Bak1 Receptor Kinasesmentioning

confidence: 99%

The brassinosteroid signal transduction pathway

Wang

Chong

et al. 2006

Cell Res

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Steroids function as signaling molecules in both animals and plants. While animal steroid hormones are perceived by nuclear receptor family of transcription factors, brassinosteroids (BR) in plants are perceived by a cell surface receptor kinase, BRI1. Recent studies have demonstrated that BR binding to the extracellular domain of BRI1 induces kinase activation and dimerization with another receptor kinase, BAK1. Activated BRI1 or BAK1 then regulate, possibly indirectly, the activities of BIN2 kinase and/or BSU1 phosphatase, which directly regulate the phosphorylation status and nuclear accumulation of two homologous transcription factors, BZR1 and BES1. BZR1 and BES1 directly bind to promoters of BR responsive genes to regulate their expression. The BR signaling pathway has become a paradigm for both receptor kinase signaling in plants and steroid signaling by cell surface receptors in general.

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“…Up to now, several key components of the BR signaling pathway have been identified through molecular and genetics studies. In Arabidopsis, BR signal is perceived by the extracellular domain of the transmembrane receptor BRI1 [7][8][9][10]. BAK1, a BRI1 co-receptor, has a similar expression pattern and subcellular localization with BRI1, and serves as a signal transducer after the BR signal is recognized by BRI1.…”

Section: Introductionmentioning

confidence: 99%

Membrane steroid-binding protein 1 (MSBP1) negatively regulates brassinosteroid signaling by enhancing the endocytosis of BAK1

et al. 2009

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Brassinosteroids (BRs) are perceived by transmembrane receptors and play vital roles in plant growth and development, as well as cell in responses to environmental stimuli. The transmembrane receptor BRI1 can directly bind to brassinolide (BL), and BAK1 interacts with BRI1 to enhance the BRI1-mediated BR signaling. Our previous studies indicated that a membrane steroid-binding protein 1 (MSBP1) could bind to BL in vitro and is negatively involved in BR signaling. To further elucidate the underlying mechanism, we here show that MSBP1 specifically interacts with the extracellular domain of BAK1 in vivo in a BL-independent manner. Suppressed cell expansion and BR responses by increased expression of MSBP1 can be recovered by overexpressing BAK1 or its intracellular kinase domain, suggesting that MSBP1 may suppress BR signaling through interacting with BAK1. Subcellular localization studies revealed that both MSBP1 and BAK1 are localized to plasma membrane and endocytic vesicles and MSBP1 accelerates BAK1 endocytosis, which results in suppressed BR signaling by shifting the equilibrium of BAK1 toward endosomes. Indeed, enhanced MSBP1 expression reduces the interaction between BRI1 and BAK1 in vivo, demonstrating that MSBP1 acts as a negative factor at an early step of the BR signaling pathway.

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BRI1 is a critical component of a plasma-membrane receptor for plant steroids

Cited by 741 publications

References 23 publications

The Sink-Specific Plastidic Phosphate Transporter PHT4;2 Influences Starch Accumulation and Leaf Size in Arabidopsis

The Sink-Specific Plastidic Phosphate Transporter PHT4;2 Influences Starch Accumulation and Leaf Size in Arabidopsis

The brassinosteroid signal transduction pathway

Membrane steroid-binding protein 1 (MSBP1) negatively regulates brassinosteroid signaling by enhancing the endocytosis of BAK1

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