Date Published: January 8, 2010
Publisher: Public Library of Science
Author(s): Yi-Feng Chen, Zhiyong Gao, Robert J. Kerris, Wuyi Wang, Brad M. Binder, G. Eric Schaller, Karin Schumacher. http://doi.org/10.1371/journal.pone.0008640
Abstract: The gaseous plant hormone ethylene is perceived in Arabidopsis thaliana by a five-member receptor family composed of ETR1, ERS1, ETR2, ERS2, and EIN4.
Partial Text: The gaseous plant hormone ethylene (C2H4) regulates a broad spectrum of developmental and physiological processes including germination, growth, senescence, ripening, and responses to biotic and abiotic stress , . In Arabidopsis, ethylene is perceived by a receptor family composed of ETR1, ERS1, ETR2, ERS2, and EIN4 , , . The ethylene receptors have a similar overall modular structure, each containing three conserved transmembrane domains near the N-terminus, followed by a GAF domain of unknown function, and then signal output motifs in the C-terminal half. Although similar, the ethylene receptors can be divided into two subfamilies based on phylogenetic analysis and some shared structural features, subfamily 1 being composed of ETR1 and ERS1, subfamily 2 being composed of ETR2, ERS2, and EIN4 , , .
Signal transduction involves protein-protein interactions and thus receptors typically function as multicomponent complexes or protein complexes , . We find that all five ethylene receptors of Arabidopsis are solubilized from membranes as high-molecular-mass protein complexes, consistent with a protein complex being the functional unit for ethylene perception and signal transduction. Among the types of protein-protein interactions possible in a complex are homo- and hetero-oligomeric interactions, non-obligate and obligate interactions, and transient and permanent interactions . Characterization of the ethylene receptors indicates that multiple types of interactions play roles in formation of the protein complex.