Abstract
Receptor tyrosine kinases control many critical processes in metazoans, but these enzymes appear to be absent in plants. Recently, two Arabidopsis receptor kinases--BRASSINOSTEROID INSENSITIVE 1 (BRI1) and BRI1-ASSOCIATED KINASE1 (BAK1), the receptor and coreceptor for brassinosteroids--were shown to autophosphorylate on tyrosines. However, the cellular roles for tyrosine phosphorylation in plants remain poorly understood. Here, we report that the BRI1 KINASE INHIBITOR 1 (BKI1) is tyrosine phosphorylated in response to brassinosteroid perception. Phosphorylation occurs within a reiterated [KR][KR] membrane targeting motif, releasing BKI1 into the cytosol and enabling formation of an active signaling complex. Our work reveals that tyrosine phosphorylation is a conserved mechanism controlling protein localization in all higher organisms.
Publication types
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Research Support, N.I.H., Extramural
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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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Amino Acid Motifs
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Amino Acid Sequence
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Arabidopsis / enzymology
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Arabidopsis / genetics
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Arabidopsis / metabolism*
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Arabidopsis Proteins / chemistry
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Cell Membrane / metabolism*
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Conserved Sequence
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Enzyme Activation*
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Models, Molecular
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Mutation
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Phosphorylation
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Protein Binding
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Protein Kinases / chemistry
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Protein Kinases / genetics
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Protein Kinases / metabolism*
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Protein Serine-Threonine Kinases / metabolism
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Protein Structure, Tertiary
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Protein Transport
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Sequence Alignment
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Tyrosine / metabolism*
Substances
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Arabidopsis Proteins
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BKI1 protein, Arabidopsis
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Tyrosine
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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