Biology subjects

Feraru, E.

Publications and source records attributed to Feraru, E..

5 recordsLinked to original sources

bioRxiv2025

ERAD machinery controls the conditional turnover of PIN-LIKES in plants

Auxin is a crucial phytohormone that regulates plant development and facilitates dynamic responses to environmental changes through subcellular control mechanisms. PIN-LIKES (PILS) are auxin transport facilitators at the endoplasmic reticulum (ER) that mediate nuclear auxin abundance and signalling. While the posttranslational regulation of PILS is important for acclimating growth responses, the molecular mechanisms involved remain largely unknown. This study demonstrates that components of the ER-associated degradation (ERAD) machinery regulate the proteasome-dependent degradation of functional PILS proteins under non-stressed conditions. We further reveal that both internal and external signals utilise the ERAD complex to differentially modulate the turnover rates of PILS proteins. Our findings uncover an additional physiological role of the ERAD complex in regulating PILS protein turnover. This finding uncovers the interplay between protein homeostasis at the ER and growth regulation, opening new molecular avenues into how plants acclimate to internal and external cues.

plant biology↗

bioRxiv2023

Endoplasmic-Reticulum stress controls PIN-LIKES abundance and thereby growth adaptation

Extreme environmental conditions eventually limit plant growth (1, 2). Here we reveal an unprecedented mechanism that enables multiple external cues to get integrated into auxin-dependent growth programs in Arabidopsis thaliana. Our forward genetics approach on dark grown hypocotyls uncovered that an imbalance in membrane lipids enhances the protein abundance of PIN-LIKES (PILS) (3-5) auxin transport facilitators at the endoplasmic reticulum (ER), which thereby limits nuclear auxin signaling and growth rates. We show that this subcellular response relates to ER stress signaling, which directly impacts on PILS protein turnover in a tissue-dependent manner. This mechanism allows PILS proteins to integrate environmental input with phytohormone auxin signaling, contributing to stress-induced growth adaptation in plants.

plant biology↗

bioRxiv2022

PILS proteins provide a homeostatic feedback on auxin signaling output

Auxin is a crucial regulator of plant growth and development. Multiple internal and external signals converge at the regulation of auxin metabolism, intercellular transport, and signaling (Pernisova and Vernoux, 2021; Anfang and Shani, 2021). Considering this complexity, it remains largely unknown how plant cells monitor and ensure the homeostasis of auxin responses. PIN-LIKES (PILS) intracellular auxin transport facilitators at the endoplasmic reticulum (ER) are suitable candidates to buffer cellular auxin responses, because they limit nuclear abundance and signaling of auxin (Barbez et al., 2012; Beziat et al., 2017; Feraru et al., 2019; Sun et al., 2020). We used forward genetics to identify mechanisms that define the PILS6 protein abundance and thereby auxin signaling outputs. We screened for gloomy and shiny pils (gasp) mutants that define the levels of PILS6-GFP under a constitutive promoter. In this study, we show that GASP1 encodes for an uncharacterized RING/U-box superfamily protein and impacts on auxin signaling output. We conclude that the low auxin signaling in gasp1 mutants correlates with reduced abundance of PILS proteins, such as PILS5 and PILS6, which consequently balances auxin-related phenotypes. In agreement, we show that high and low auxin conditions increase and reduce PILS6 protein levels, respectively. Accordingly, non-optimum auxin concentrations are buffered by alterations in PILS6 abundance, consequently leading to homeostatic auxin output regulation. We envision that this feedback mechanism provides robustness to auxin-dependent plant development.

plant biology↗

bioRxiv2019

Brassinosteroid signaling controls PILS-dependent nuclear auxin input in Arabidopsis thaliana

Auxin and brassinosteroids (BR) are crucial growth regulators and display overlapping functions during plant development. Here, we reveal an alternative phytohormone crosstalk mechanism, revealing that brassinosteroid signaling controls nuclear abundance of auxin. We performed a forward genetic screen for imperial pils (imp) mutants that enhance the overexpression phenotypes of PIN-LIKES (PILS) putative intracellular auxin transport facilitator. Here we report that the imp1 mutant is defective in the brassinosteroid-receptor BRI1. Our data reveals that BR signaling transcriptionally and posttranslationally represses accumulation of PILS proteins at the endoplasmic reticulum, thereby increasing nuclear abundance and signaling of auxin. We demonstrate that this alternative phytohormonal crosstalk mechanism integrates BR signaling into auxin-dependent organ growth rates and likely has widespread importance for plant development.

plant biology↗

bioRxiv2018

PILS6 is a temperature-sensitive regulator of nuclear auxin input and organ growth in Arabidopsis thaliana

Global warming is threatening plant productivity, because plant growth is highly sensitive to elevated temperatures. High temperature (HT) triggers the auxin biosynthesis-dependent growth in aerial tissues. On the other hand, the contribution of auxin to HT-induced root growth is currently under debate. Here we show that the putative intracellular auxin carrier PIN-LIKES 6 (PILS6) is a negative regulator of organ growth and that its abundance is highly sensitive to HT. PILS6 localises to the endoplasmic reticulum (ER) and limits the nuclear availability of auxin, consequently reducing the auxin signalling output. HT represses the transcription and protein abundance of PILS6 specifically in the root tip, which impacts on PILS6-dependent root organ growth rates. Accordingly, we hypothesize that PILS6 is part of a novel mechanism, linking HT to auxin responses in roots.

plant biology↗