Proteomics Studies of Brassinosteroid Signal Transduction Using Prefractionation and Two-dimensional DIGE

• DOI: 10.1074/mcp.m700358-mcp200
• Publication Date: 2008-01-09T03:24:42Z
• Authors: Wenqiang Tang; Zhiping Deng; Juan A. Oses-Prieto; Nagi Suzuki; Shengwei Zhu; Xin Zhang; Alma L. Burlingame; Zhi-Yong Wang
• Keywords: Phosphoprotein; Brassinosteroid

Signal transduction involves posttranslational modifications and protein-protein interactions, which can be studied by proteomics. In Arabidopsis, the steroid hormone (brassinosteroid (BR)) binds to extracellular domain of a receptor kinase (BRI1) initiate phosphorylation/dephosphorylation cascade that controls gene expression plant growth. Here we detected early BR signaling events identified response proteins using prefractionation two-dimensional (2-D) DIGE. Proteomic changes induced rapidly treatments were in phosphoprotein plasma membrane (PM) fractions 2-D DIGE but not total protein extracts. LC-MS/MS analysis gel spots 19 BR-regulated PM six from fractions. These include BAK1 BZR1 transcription factor pathway. Both showed spot shifts consistent with phosphorylation. addition, vivo phosphorylation sites for BZR1, two tetratricopeptide repeat proteins, phosphoenolpyruvate carboxykinase (PCK1). Overexpression novel BR-induced (DREPP) partially suppressed phenotypes BR-deficient mutant, demonstrating its important function responses. Our study demonstrates coupled is powerful approach studying signal transduction.