P-017 - CLEAN-LORE – Controlled activation of LORE kinase signaling using receptor chimera

The Arabidopsis PRR LORE (LIPOOLIGOSACCHARIDE-SPECIFIC REDUCED ELICITATION) is an S-domain receptor kinase that plays a crucial role in triggering plant immune signaling by sensing medium chain 3-hydroxy fatty acids (mc-3-OH-FAs). Previously, LORE was shown to undergo homodimerization through its extracellular and transmembrane domain, which is essential for initiating immune signalling. Transient overexpression of full-length LORE in Nicotiana benthamiana showed a necrosis-associated phenotype, indicating ligand-independent dimerization and activation of LORE signalling. This constitutive activation poses a challenge to use heterologous systems for studying LORE phosphorylation and interactions with other proteins under controlled conditions. To overcome this limitation, this project aims to control homomerization-mediated autoactivation of LORE through an extracellular domain swap approach. The Leucine Rich Repeat (LRR)-type EF-Tu receptor, EFR, is a well characterized PRR. Unlike LORE, EFR recognizes elf18 and heterodimerizes with the co-receptor BAK1. Elf18 acts as a molecular glue and facilitates interactions between the extracellular domains of EFR and BAK1. Hence, EFR-LORE and BAK1-LORE chimeric receptors were generated to enable ligand-dependent activation via elf18-induced interactions. Looking ahead, we aim to leverage the CLEAN-LORE system to understand the effects of LORE intracellular domain phosphorylation and activation on interactions with other proteins.