Author: Panagiotis Moschou

New breakthrough paper from our group

by Panagiotis Moschou

https://www.embopress.org/doi/full/10.15252/embj.2022111885

An actin remodeling role for Arabidopsis processing bodies revealed by their proximity interactome

Abstract

Cellular condensates can comprise membrane-less ribonucleoprotein assemblies with liquid-like properties. These cellular condensates influence various biological outcomes, but their liquidity hampers their isolation and characterization. Here, we investigated the composition of the condensates known as processing bodies (PBs) in the model plant Arabidopsis thaliana through a proximity-biotinylation proteomics approach. Using in situprotein–protein interaction approaches, genetics and high-resolution dynamic imaging, we show that processing bodies comprise networks that interface with membranes. Surprisingly, the conserved component of PBs, DECAPPING PROTEIN 1 (DCP1), can localize to unique plasma membrane subdomains including cell edges and vertices. We characterized these plasma membrane interfaces and discovered a developmental module that can control cell shape. This module is regulated by DCP1, independently from its role in decapping, and the actin-nucleating SCAR–WAVE complex, whereby the DCP1–SCAR–WAVE interaction confines and enhances actin nucleation. This study reveals an unexpected function for a conserved condensate at unique membrane interfaces.

Processing body (PB) composition remains incompletely characterized. Here, proximity interactome profiling of Arabidopsis PBs describes their dynamic nature and identifies the role of PB components in actin-dependent regulation of tissue growth.

  • The protein composition and proximity-dependent interactome (“proxitome”) of plant processing bodies are determined by proximity biotinylation approaches.
  • Plant processing bodies are dynamic and include proteins linked to membrane remodeling and actin dynamics.
  • Processing body component DCP1 associates with the plasma membrane and the actin-nucleating complex SCAR/WAVE at cell vertices.
  • DCP1 phosphorylation status regulates its localization and root growth.