Endosomal signaling of the tomato leucine-rich repeat receptor-like protein LeEix2

Miya Sharfman, Maya Bar, Marcelo Ehrlich, Silvia Schuster, Shiri Melech-Bonfil, Ran Ezer, Guido Sessa, Adi Avni

Research output: Contribution to journalArticlepeer-review

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.

Original languageEnglish
Pages (from-to)413-423
Number of pages11
JournalPlant Journal
Volume68
Issue number3
DOIs
StatePublished - Nov 2011

Keywords

  • Endocytosis
  • Endosomal signaling
  • Ethylene-inducing xylanase
  • Reactive oxygen species
  • Signal transduction

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