Ethylene receptors function as components of high-molecular-mass protein complexes in Arabidopsis.
BACKGROUND
The gaseous plant hormone ethylene is perceived in Arabidopsis thaliana by a five-member receptor family composed of ETR1, ERS1, ETR2, ERS2, and EIN4.


RESULTS
Gel-filtration analysis of ethylene receptors solubilized from Arabidopsis membranes demonstrates that the receptors exist as components of high-molecular-mass protein complexes. The ERS1 protein complex exhibits an ethylene-induced change in size consistent with ligand-mediated nucleation of protein-protein interactions. Deletion analysis supports the participation of multiple domains from ETR1 in formation of the protein complex, and also demonstrates that targeting to and retention of ETR1 at the endoplasmic reticulum only requires the first 147 amino acids of the receptor. A role for disulfide bonds in stabilizing the ETR1 protein complex was demonstrated by use of reducing agents and mutation of Cys4 and Cys6 of ETR1. Expression and analysis of ETR1 in a transgenic yeast system demonstrates the importance of Cys4 and Cys6 of ETR1 in stabilizing the receptor for ethylene binding.


CONCLUSIONS
These data support the participation of ethylene receptors in obligate as well as ligand-dependent non-obligate protein interactions. These data also suggest that different protein complexes may allow for tailoring of the ethylene signal to specific cellular environments and responses.
Chen
Yi-Feng
YF
Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America.
Gao
Zhiyong
Z
Kerris
Robert J
RJ
Wang
Wuyi
W
Binder
Brad M
BM
Schaller
G Eric
GE
D017360:Arabidopsis / Q000378:metabolism*; D002850:Chromatography, Gel; D005030:Ethylenes / Q000378:metabolism*; D008970:Molecular Weight; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D005030:Ethylenes; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; C036216:ethylene