Abstract
Brassinosteroids regulate plant growth and development through a protein complex that includes the leucine-rich repeat receptor-like protein kinase (LRR-RLK) brassinosteroid-insensitive 1 (BRI1). Activation tagging was used to identify a dominant genetic suppressor of bri1, bak1-1D (bri1-associated receptor kinase 1-1Dominant), which encodes an LRR-RLK, distinct from BRI1. Overexpression of BAK1 results in elongated organ phenotypes, while a null allele of BAK1 displays a semidwarfed phenotype and has reduced sensitivity to brassinosteroids (BRs). BAK1 is a serine/threonine protein kinase, and BRI1 and BAK1 interact in vitro and in vivo. Expression of a dominant-negative mutant allele of BAK1 causes a severe dwarf phenotype, resembling the phenotype of null bri1 alleles. These results indicate BAK1 is a component of BR signaling.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Alleles
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Arabidopsis
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Arabidopsis Proteins / genetics*
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Arabidopsis Proteins / metabolism
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Brassinosteroids
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Cholestanols / pharmacology
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Enzyme Activation
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Gene Expression Regulation, Enzymologic
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Gene Expression Regulation, Plant
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Hydroxysteroids / metabolism*
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Phenotype
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Phosphorylation
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Protein Kinases / genetics
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Protein Kinases / metabolism*
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Protein Serine-Threonine Kinases / genetics*
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Protein Serine-Threonine Kinases / metabolism*
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Repressor Proteins / genetics
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Repressor Proteins / metabolism*
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Signal Transduction / physiology*
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Steroids, Heterocyclic / pharmacology
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Tissue Distribution
Substances
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Arabidopsis Proteins
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Brassinosteroids
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Cholestanols
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Hydroxysteroids
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Membrane Proteins
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Repressor Proteins
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Steroids, Heterocyclic
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Protein Kinases
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BAK1 protein, Arabidopsis
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BRI1 protein, Arabidopsis
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Protein Serine-Threonine Kinases
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brassinolide