Kanne, J. V. | Search bioRxiv

bioRxiv2025

A moss N-Acetyltransferase-MAPK protein controls 2D to 3D developmental transition via acetylation and phosphorylation changes

Post-translational modifications (PTMs) finetune plant responses to developmental and environmental cues by impacting protein activity, stability, localization and interaction landscape. In this study we identified a moss specific protein which combines two common PTMs: acetylation and phosphorylation. This protein originated from the fusion of a MAPK with an N-acetyltransferase, for which we named it Rosetta NATD-MAPK 1 (RAK1). Using biochemical methods, we demonstrated that RAK1 has acetyltransferase activity that is enhanced by activation of its MAPK domain. Phenotypical studies of rak1 knockout mutants revealed a role for RAK1 in the regulation of the 2D-to-3D growth transition. Through Mass Spectrometry we verified that defective 2D-to-3D transition in the mutants was caused by differentially regulated acetylation and phosphorylation events associated to metabolic reprogramming and 3D differentiation. Collectively, this study uncovers a previously unknown multidomain protein and provides insights into the interplay of PTMs during developmental reprogramming. TeaserAcetylation and phosphorylation changes modulate the 2D to 3D developmental transition in Physcomitrium patens.

plant biology↗

bioRxiv2024

Cross-species interactome analysis uncovers a conserved selective autophagy mechanism for protein quality control in plants

Selective autophagy is a fundamental protein quality control pathway that safeguards proteostasis by degrading damaged or surplus cellular components, particularly under stress. This process is orchestrated by selective autophagy receptors (SARs) that direct specific cargo for degradation. While significant strides have been made in understanding the molecular framework of selective autophagy, the diversity of SAR repertoires across species remain largely unexplored. Through a comparative interactome analysis across five model organisms, we identified a suite of conserved and lineage-specific SAR candidates. Among these, we validated CESAR as a conserved SAR critical for proteostasis under heat stress. CESAR specifically facilitates the degradation of hydrophobic, ubiquitinated protein aggregates and is indispensable for heat stress tolerance. Our study offers a rich resource for SAR discovery and positions CESAR as a pivotal regulator of proteostasis, with broad implications for improving stress resilience in plants.

plant biology↗