Heterotrimeric G proteins interact with defense-related receptor-like kinases in Arabidopsis

J Plant Physiol. 2015 Sep 1;188:44-8. doi: 10.1016/j.jplph.2015.09.005. Epub 2015 Sep 24.

Abstract

Heterotrimeric G proteins (G-proteins) are versatile signaling elements conserved in Eukaryotes. In animals G-proteins relay signals from 7-transmembrane spanning G protein-coupled receptors (GPCRs) to intracellular downstream effectors; however, the existence of GPCRs in plants is controversial. Contrastingly, a surplus of receptor-like kinases (RLKs) provides signal recognition at the plant cell surface. It is established that G proteins are involved in plant defense and suggested that they relay signals from defense-related RLKs. However, it is unclear how the signaling is conducted, as physical interaction between the RLKs and G proteins has not been demonstrated. Using yeast split-ubiquitin system and Bimolecular Fluorescence Complementation assays, we demonstrate physical interaction between the Gα, Gγ1 and Gγ2 subunits, and the defense-related RD-type receptor like kinases CERK1, BAK1 and BIR1. At the same time, no interaction was detected with the non-RD RLK FLS2. We hypothesize that G-proteins mediate signal transduction immediately downstream of the pathogenesis-related RLKs.

Keywords: Arabidopsis; Heterotrimeric G proteins; Plant defence; Protein–protein interaction; Receptor-like kinases (RLKs).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Gene Expression Regulation, Plant*
  • Heterotrimeric GTP-Binding Proteins / genetics*
  • Heterotrimeric GTP-Binding Proteins / metabolism
  • Protein-Serine-Threonine Kinases / genetics*
  • Protein-Serine-Threonine Kinases / metabolism
  • Signal Transduction*

Substances

  • Arabidopsis Proteins
  • Protein-Serine-Threonine Kinases
  • Heterotrimeric GTP-Binding Proteins