Functional Expression of the Ectodomain of Plant Receptor Kinases in Plant Suspension Culture

Extracellular signals are usually perceived by membrane-localized receptors that transduce intercellular signals to activate various pathways. In plants, single transmembrane receptor kinases act as receptors for extracellular signals. Endogenous secreted peptide hormones have been recognized as novel signaling molecules, functioning through the formation of ligand-receptor pairs in plants. Recently, research on plant peptide hormone-receptor interactions based on the structural biology approach has greatly improved; however, the dissociation constant of recombinant receptor molecules expressed in insect cells using the baculovirus expression system is relatively low. We introduce here a method for creating a stable and functional homogeneous expression system for plant receptor kinases using tobacco BY-2 cells while maintaining conventional ligand-binding activity. This strategy will help improve our understanding of plant endogenous peptide ligand-receptor interactions.