title: Plant G-Proteins Come of Age: Breaking the Bond with Animal Models.
abstract: G-proteins are universal signal transducers mediating many cellular responses. Plant G-protein signaling has been modeled on the well-established animal paradigm but accumulated experimental evidence indicates that G-protein-dependent signaling in plants has taken a very different evolutionary path. Here we review the differences between plant and animal G-proteins reported over past two decades. Most importantly, while in animal systems the G-protein signaling cycle is activated by seven transmembrane-spanning G-protein coupled receptors, the existence of these type of receptors in plants is highly controversial. Instead plant G-proteins have been proven to be functionally associated with atypical receptors such as the Arabidopsis RGS1 and a number of receptor-like kinases. We propose that, instead of the GTP/GDP cycle used in animals, plant G-proteins are activated/de-activated by phosphorylation/de-phosphorylation. We discuss the need of a fresh new look at these signaling molecules and provide a hypothetical model that departs from the accepted animal paradigm.
authors.affiliation: School of Agriculture and Food Sciences, University of Queensland Brisbane, QLD, Australia.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Trusov
authors.affiliation: School of Agriculture and Food Sciences, University of Queensland Brisbane, QLD, Australia.
authors.forename: José R
authors.initials: JR
authors.lastname: Botella
keywords: control of plant development; extra-large G-proteins; heterotrimeric G-proteins; plant defense; plant signaling; receptor-like kinases