Journal Article

Mammalian Melatonin Agonist Pharmaceuticals Stimulate Rhomboid Proteins in Plants

Yasunaga, Adam B., Erland, Lauren A. E., Dumigan, Christopher R., Murch, Susan J., Pun, Winnie, Frolova, Liubov, Li, Isaac T. S., Deyholos, Michael K., Forsyth, Jillian A.

2022

Overview

Melatonin is a human neurotransmitter and plant signalling metabolite that perceives and directs plant metabolism. The mechanisms of melatonin action in plants remain undefined. We hypothesized that roots have a melatonin-specific receptor and/or transporter that can respond to melatonin-mediating pharmaceuticals. To test this hypothesis Arabidopsis seedlings were grown with melatonin pharmaceutical receptor agonists: ramelteon and tasimelteon, and/or antagonists: luzindole and 4-P-PDOT. Ramelteon was found both to mimic and competitively inhibit melatonin metabolism in plants. Due to the higher selectivity of ramelteon for the MT1 receptor type in humans, a sequence homology search for MT1 in Arabidopsis identified the rhomboid-like protein 7 (RBL7). In physiological studies, Arabidopsis rbl7 mutants were less responsive to ramelteon and melatonin. Quantum dot visualizations of the effects of ramelteon on melatonin binding to root cell membranes revealed a potential mechanism. We propose that RBL7 is a melatonin-interacting protein that directs root architecture and growth in a mechanism that is responsive to environmental factors.

• Publisher: MDPI AG,MDPI
• Subject: Agonists / Animals / Antagonists / Antioxidants / Arabidopsis / Arabidopsis - genetics / Arabidopsis - metabolism / Cell membranes / Environmental factors / Experiments / Homology / Humans / Localization / Mammals / Mammals - metabolism / Melatonin / Melatonin - pharmacology / Plant growth / quantum dot / Quantum dots / ramelteon / Receptor, Melatonin, MT1 - agonists / Receptor, Melatonin, MT1 - metabolism / Receptor, Melatonin, MT2 - agonists / Receptor, Melatonin, MT2 - metabolism / rhomboid / Seedlings / Seeds / serotonin / tasimelteon