Kendrick, Mandy , Shockey, Jason A , Ding, Wenming , Chang, Caren .
An Ethylene Receptor Interacting Protein is a Negative Regulator of Ethylene Responses.
Ethylene is a gaseous plant hormone, having profound effects on many developmental processes. In Arabidopsis ethylene is perceived by a family of five receptors that share sequence similarity to prokaryotic two-component systems, which are comprised of histidine kinase and receiver domains. Acting downstream of the five receptors is CTR1, a putative MAPKKK. CTR1 physically interacts with ETR1 in both the yeast-two-hybrid (Y2H) and in vitro pull down assays.
To isolate additional components of this signaling pathway, we used the Y2H assay to screen for proteins that interacted with a truncated form of ETR1, containing the histidine kinase and receiver domains. Of the 29 clones (representing 27 genes) isolated from the screen, EIP1 (ETR-INTERACTING PROTEIN1) was of interest because it also interacted with the CTR1 N-terminal region in the Y2H. Both the EIP1-ETR1 and CTR1-ETR1 Y2H interactions are disrupted when a D659E mutation is created in a conserved Asp residue on the ETR1 receiver domain. (Based on sequence conservation, this Asp residue is the acceptor of phosphate transfer from the phosphorylated histidine, although this has not been shown to occur in the ethylene receptors.) Phenotypic analysis shows that Arabidopsis EIP1 t-DNA insertion lines are hypersensitive when grown in the presence of exogenous ethylene, and EIP1 overexpression lines are insensitive to ethylene, indicating that EIP1 is a negative regulator of ethylene responses. EIP1 encodes a novel 412 residue protein with no conserved motifs. It is predicted to have one transmembrane domain. We are currently carrying out further genetic analysis of EIP1 in order to elucidate its role in ethylene signaling.
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Caren Chang Lab, Protein Interactions
1 - University of Maryland, Dept. of Cell Biology and Molecular Genetics, H.J. Patterson Hall; Room 4102, College Park, MD, 20742, USA
2 - The George Washington University, Dept. of Biological Sciences
3 - University of Maryland
4 - University of Maryland, Cell Biology & Molecular Genetics
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM