The NPH3-domain protein NRL5 is a plant specific type of GTPase essential for drought resistance

Abstract

AbstractIntracellular trafficking is essential to maintain the plasma membrane-cell wall interface, a site where environmental stimuli such as limited water availability can be perceived. However, the identity of plant trafficking regulators, and their relationship to drought resistance, is unclear. An amino acid substitution in the Non-Phototrophic Hypocotyl3 (NPH3) domain of NPH3/RPT2-Like5 (NRL5)/Naked Pins in Yucca8 (NPY8) causes extreme drought sensitivity due to mis-regulated proline metabolism. This NPH3-domain mutation inhibits NRL5 GTPase activity, disrupts interaction with RAB small GTPases and the SNARE proteins VAMP721/722, and diminishes NRL5 polar localization. Our finding that the NPH3 domain is a plant specific type of GTPase participating in intracellular trafficking provides a basis to understand NPH3-domain function in diverse processes including abiotic stress resistance, hormone signaling and maintenance of cellular polarity.One-Sentence SummaryNRL5 mediates safe proline accumulation for drought resistance and has GTP-dependent interaction with trafficking-associated RAB and VAMP proteins.