Abstract
Lines of evidence suggest that a considerable amount of cell-to-cell interaction in plants is mediated by small secreted peptides. A sulfated peptide, PSK, is one of such example. PSK positively regulates cellular potential for growth via binding to surface LRR receptor kinase PSKR1. We also identified a novel tyrosine-sulfated glycopeptide in Arabidopsis based on exhaustive LC-MS analysis targeting tyrosine-sulfated peptides. This peptide, which we have named PSY1, significantly promotes cellular proliferation in a similar manner to that of PSK. Perception of PSY1 is dependent on LRR-RK whose two paralogs are involved in perception of PSK. Triple mutations in these LRR-RKs resulted in dwarfism due to decreases in cell number and cell size. We have also established a strategy for functional immobilization of plant RLKs on microbeads. Our RLK microbeads can be used for receptor array construction and receptor-based ligand fishing.
