Traffic control for receptors at the host-microbe interface

PL-1.4 - Host membranes respond to microbial perception and different membrane domains enable host cells to perform the functions they require in mediating immunity. Focusing on how the membrane trafficking network responds to microbial attack, we have dissected the spatio - temporal redistribution of membranes cargoes such as the pattern recognition receptors (PRRs). FLS2 is a known plasma membrane-resident receptor kinase PRR that enters two distinct endosomal trafficking routes depending on its activation status. To this end, ligand - induced late endosomal trafficking of FLS2 requires an active receptor complex. FLS2 endocytosis mediated by clathrin and involves sorting by the ESCRT machinery. Ligand-induced endocytosis is conserved across different PRR protein families as well as across different plant species. By studying the EFR and PEPR1/2 receptor kinases, we identified a common endosomal pathway, which regulates the removal of activated PRRs from the plasma membrane. This expands into the family of receptor-like protein type PRRs, of which the Cf-4-SOBIR1 constitutive complex forms a tripartite interaction with BAK1/SERK3 upon Avr4 perception, required to induce the endocytosis of the complex. Our findings show that the mechanism of endocytosis is employed in regulating the spatio-temporal dynamics of PRRs, which can facilitate the uptake of microbial molecules as observed for lagellin, and is involved in specific immun e responses such as the closure of stomata.