The study reveals that REMORIN protein evolution is primarily driven by diversification of their conserved C-terminal domain, defining four major clades. Structural bioinformatics predicts a common membrane‑binding interface with diverse curvatures and lengths, and suggests that some REMs can form C‑terminal‑mediated oligomers, adding complexity to membrane organization.

The study demonstrates that subfamily I ethylene receptors form the core ethylene‑sensing module and act epistatically over subfamily II receptors, uniquely possessing Ca2+‑permeable channel activity that drives ethylene‑induced cytosolic calcium influx. This reveals a mechanistic link whereby subfamily I receptors integrate hormone perception with calcium signaling in plants.

The study provides direct evidence for a chloroplast unfolded protein response (cpUPR) by expressing engineered, folding‑defective ferredoxin‑NADP reductase variants in plant chloroplasts, which induced upregulation of chloroplast quality‑control proteins. Quantitative proteomics showed that the response magnitude correlated with the severity of protein misfolding, and misfolded‑protein expression conferred heat‑tolerance, highlighting cpUPR as a specific stress response that can improve plant fitness.

The study used quantitative proteomics and co‑fractionation mass spectrometry to uncover rapid ethylene‑induced changes in protein abundance and complex formation during early seedling development, revealing extensive protein multimerization events that correlate with hypocotyl growth modulation. Small‑scale validation confirmed several identified proteins impact hypocotyl development, highlighting novel components of ethylene‑mediated growth regulation.