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United States Department of Agriculture

Agricultural Research Service

Title: 14-3-3 Proteins Bind to the Brassinosteroid Receptor Kinase, BRI1 and are Positive Regulators of Brassinosteroid Signaling)

Author
item Oh, Man Ho
item Wang, Xiaofeng
item Clouse, Steven
item Huber, Steven

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2009
Publication Date: 7/18/2009
Citation: Oh, M., Wang, X., Clouse, S.D., Huber, S.C. 2009. 14-3-3 Proteins Bind to the Brassinosteroid Receptor Kinase, BRI1 and are Positive Regulators of Brassinosteroid Signaling [abstract]. American Society of Plant Biologists Annual Meeting. Paper No. P35029.

Interpretive Summary:

Technical Abstract: Multiple members of the 14-3-3 protein family have been found in all eukaryotes, the biological functions of which are to interact physically with specific client proteins and thereby effect a change in the client. Thus, 14-3-3s are involved in many processes. The plant brassinosteroid (BR) receptor, BRASSINOSTEROID INSENSITIVE 1 (BRI1), is a member of the large family of leucine-rich repeat receptor-like kinases (LRR-RLKs) that contain cytoplasmic protein kinase domains. At least two LRR-RLKs are involved in BR perception and signal transduction: BRI1 and BRI1-associated receptor kinase 1 (BAK1). Pharmacological and molecular genetic results suggested that 14-3-3s are positive regulators of BR signaling. 14-3-3 proteins CO-IP with BRI1-Flag and both BRI1 and BAK1 bind to 14-3-3 proteins in vitro. The binding of recombinant 14-3-3<omega> to the recombinant cytoplasmic domain of BRI1 and BAK1 in vitro is dependent on autophosphorylation of the receptor kinase and is strongly stimulated by Mg2+. Generally, 14-3-3 proteins bind to pSer/pThr sites of client proteins. We determined that 14-3-3<omega> binds to the juxtamembrane domain of BRI1-CD and mutagenesis analysis suggest that Ser-858 and Thr-872 are involved in 14-3-3 binding and are critical for plant growth and development in BR signaling. The potential for serine and threonine phosphorylation to be directly involved in 14-3-3 binding is established, and adds a new dimension to the functionality of these signaling proteins.

Last Modified: 8/24/2016
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