title: Endosomal signaling of the tomato leucine-rich repeat receptor-like protein LeEix2.
abstract: Extracellular leucine-rich repeat (LRR) receptor-like proteins (RLPs) represent a unique class of cell-surface receptors, as they lack a functional cytoplasmic domain. Our knowledge of how RLPs that do not contain a kinase or Toll domain function is very limited. The tomato RLP receptor LeEix2 signals to induce defense responses mediated by the fungal protein ethylene-inducing xylanase (EIX). The movement of FYVE-positive endosomes before and after EIX application was examined using spinning disc confocal microscopy. We found that while FYVE-positive endosomes generally observe a random movement pattern, following EIX application a subpopulation of FYVE-positive endosomes follow a directional movement pattern. Further, cellular endosomes travel greater distances at higher speeds following EIX application. Time-course experiments conducted with specific inhibitors demonstrate the involvement of endosomal signaling in EIX-triggered defense responses. Abolishing the existence of endosomes or the endocytic event prevented EIX-induced signaling. Endocytosis/endosome inhibitors, such as Dynasore or 1-butanol, inhibit EIX-induced signaling. Moreover, treatment with Endosidin1, which inhibits an early step in plasma membrane/endosome trafficking, enhances the induction of defense responses by EIX. Our data indicate a distinct endosomal signaling mechanism for induction of defense responses in this RLP system.
authors: Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, Tel-Aviv, Israel.
authors: Miya
authors: M
authors: Sharfman
authors: Maya
authors: M
authors: Bar
authors: Marcelo
authors: M
authors: Ehrlich
authors: Silvia
authors: S
authors: Schuster
authors: Shiri
authors: S
authors: Melech-Bonfil
authors: Ran
authors: R
authors: Ezer
authors: Guido
authors: G
authors: Sessa
authors: Adi
authors: A
authors: Avni
mesh_terms: D016923:Cell Death; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism*; D000090263:Leucine-Rich Repeat Proteins; D036701:Limonins; D018551:Solanum lycopersicum / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D000090263:Leucine-Rich Repeat Proteins; D036701:Limonins; D010940:Plant Proteins; D011506:Proteins; C105838:prieurianin