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

Citation
Zy. Wang et al., BRI1 is a critical component of a plasma-membrane receptor for plant steroids, NATURE, 410(6826), 2001, pp. 380-383
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary,Multidisciplinary,Multidisciplinary
Journal title
NATURE
ISSN journal
0028-0836 → ACNP
Volume
410
Issue
6826
Year of publication
2001
Pages
380 - 383
Database
ISI
SICI code
0028-0836(20010315)410:6826<380:BIACCO>2.0.ZU;2-7
Abstract
Most multicellular organisms use steroids as signalling molecules for physi ological and developmental regulation. Two different modes of steroid actio n have been described in animal systems: the well-studied gene regulation r esponse mediated by nuclear receptors(1,2), and the rapid non-genomic respo nses mediated by proposed membrane-bound receptors(3,4). Plant genomes do n ot seem to encode members of the nuclear receptor superfamily(5). However, a transmembrane receptor kinase, brassinosteroid-insensitive1 (BRI1), has b een implicated in brassinosteroid-responses(6,7). Here we show that BRI1 fu nctions as a receptor of brassinolide, the most active brassinosteroid. The number of brassinolide-binding sites and the degree of response to brassin olide depend on the level of BRI1 protein. The brassinolide-binding activit y co-immunoprecipitates with BRI1, and requires a functional BRI1 extracell ular domain. Moreover, treatment of Arabidopsis seedlings with brassinolide induces autophosphorylation of BRI1, which, together with our binding stud ies, shows that BRI1 is a receptor kinase that transduces steroid signals a cross the plasma membrane.