EAST LANSING, Mich. The discovery of a hormone acting like molecular glue could hold a key to bolstering plant immune systems and understanding how plants cope with environmental stress.
The study, which is featured in the Oct. 6 issue of Nature, reveals how the plant hormone jasmonate binds two proteins together an emerging new concept in hormone biology and protein chemistry. The study also identifies the receptor's crystal structure to provide the first molecular view of how plants ward off attacks by insects and pathogens.
In short, the work explains how a highly dynamic form of plant immunity is triggered, said Gregg Howe, biochemistry and molecular biology professor, who worked with fellow MSU professor Sheng Yang He on the study. The study is a collaboration between the MSU-Department of Energy Plant Research Laboratory and the University of Washington.
"In many respects, this receptor is novel in how it binds its target hormone to switch on gene expression," Howe said. "Jasmonate appears to act as molecular glue that sticks two proteins together, which sets off a chain of events leading to the immune response. Determining the structure of the receptor solves a big missing piece of the puzzle."
Earlier research conducted by Howe and He helped to unveil the mechanism of action of jasmonate, the last major plant hormone to have its signaling pathway decoded. When a plant is attacked, the jasmonate signal causes direct interaction between a family of JAZ repressor proteins and the F-box protein COI1, which works to eliminate JAZ proteins so the plant can mount a defense.
Reconstructing the molecular mechanism of jasmonate perception revealed a multicomponent signaling hub. Instead of working as a single protein, which is typical of most receptors, this new receptor is actually a co-receptor complex that consists of COI1, JAZ and a newly discovered third component, inositol pentakisphosphate, Howe said.
|Contact: Layne Cameron|
Michigan State University