Control of PILS Turnover for Developmental Acclimation in Plants

• Applicant: Professor Dr. Jürgen Kleine-Vehn
• Subject Area: Plant Cell and Developmental Biology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 559042842

Auxin, a pivotal phytohormone, orchestrates plant growth and development by integrating internal signals and environmental cues. Here we aim to advance our understanding of growth acclimation to the environment. PIN-LIKES (PILS) are putative auxin carriers, residing at the endoplasmic reticulum (ER), and have emerged as critical regulators of intracellular auxin signalling. They play essential roles in plant adaptation to environmental fluctuations such as light, temperature, and ER stress. Environmental control of PILS turnover is an important mechanism for organ growth acclimation, but the molecular mechanisms controlling PILS protein turnover and stability remain largely unexplored. This project aims to unravel the regulatory pathways governing PILS protein turnover, focusing on the role of the Endoplasmic Reticulum-Associated Degradation (ERAD) pathway. We hypothesize that ERAD-mediated regulation of PILS stability is a key mechanism by which plants modulate auxin signalling in response to environmental changes, thereby coordinating tissue-specific growth responses. Our objectives are to • elucidate the Spatiotemporal Control of ERAD-PILS Interaction: We will investigate how environmental factors and hormonal signals influence the interaction between PILS proteins and ERAD components, affecting PILS stability and function. • unravel the Molecular Mechanisms Regulating Plant Growth via PILS Stability: By identifying posttranslational modifications, particularly phosphorylation sites on PILS proteins, we aim to understand how these modifications dictate PILS turnover and auxin signalling. • address the Physiological Role of ERAD in Non-Stressed Plants: We will explore the broader functions of ERAD beyond protein quality control, assessing its role in regulating properly folded proteins like PILS under normal physiological conditions. Employing advanced techniques in molecular biology, live-cell imaging, phosphoproteomics, and genetic manipulation, this research will provide comprehensive insights into the mechanisms controlling auxin homeostasis and plant growth adaptation.

• DFG Programme: Research Grants