Differential contribution of Arabidopsis chitin receptor complex components to defense signaling and ubiquitination-dependent endocytotic removal from the plasma membrane.

In Arabidopsis, the enzymatically active lysin motif-containing receptor-like kinase (LysM-RLK) CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) and the pseudokinases LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE 5 (LYK5) and LYK4 are the core components of the canonical chitin receptor complex. CERK1 dimerizes and autophosphorylates upon chitin binding, resulting in activation of chitin signaling. In this study, we clarified and further elucidated the individual contributions of LYK4 and LYK5 to chitin-dependent signaling using mutant (combination)s and stably transformed Arabidopsis plants expressing fluorescence-tagged LYK5 and LYK4 variants from their endogenous promoters.

Signal Peptide Peptidase and PI4Kβ1/2 play opposite roles in plant ER stress response and immunity.

The Arabidopsis pi4kβ1,2 mutant is mutated in the phosphatidylinositol 4-kinase (PI4K) β1 and PI4Kβ2 enzymes which are involved in the biosynthesis of phosphatidylinositol 4-phosphate (PI4P), a minor membrane lipid with important signaling roles. pi4kβ1,2 plants display autoimmunity and shorter roots. Though the pi4kβ1,2 mutant has been extensively characterized, the source of its autoimmunity remains largely unknown.

A novel fluorescent protein pair facilitates FLIM-FRET analysis of plant immune receptor interaction under native conditions.

Elucidating protein-protein interactions is crucial for our understanding of molecular processes within living organisms. Microscopy-based techniques can detect protein-protein interactions in vivo at the single-cell level and provide information on their subcellular location. Fluorescence lifetime imaging microscopy (FLIM)-Förster resonance energy transfer (FRET) is one of the most robust imaging approaches, but it is still very challenging to apply this method to proteins which are expressed under native conditions.