Tyrosine phosphorylation controls brassinosteroid receptor activation by triggering membrane release of its kinase inhibitor
- Yvon Jaillais1,2,4,
- Michael Hothorn1,4,
- Youssef Belkhadir1,2,5,
- Tsegaye Dabi1,2,
- Zachary L. Nimchuk3,
- Elliot M. Meyerowitz3 and
- Joanne Chory1,2,6
- 1Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA;
- 2Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, California 92037, USA;
- 3Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125, USA
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↵4 These authors contributed equally to this work.
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.
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Footnotes
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↵6 Corresponding author.
E-MAIL chory{at}salk.edu; FAX (858) 558-6379.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.2001911.
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Supplemental material is available for this article.
- Received October 11, 2010.
- Accepted December 20, 2010.
- Copyright © 2011 by Cold Spring Harbor Laboratory Press
