ROOT PHOTOTROPISM 2 (RPT2) is a KAT1 potassium channel regulator required for its accumulation

This is the authors' abstract. We don't add key points for this paper.

In plants, inward rectifying potassium channels regulate potassium entry into guard cells and are a key factor controlling stomatal opening. KAT1 is a major inward rectifying potassium channel present in Arabidopsis thaliana guard cell membranes. The identification of regulators of channels like KAT1 is a promising approach for the development of strategies to improve plant drought tolerance. Using a high-throughput Split-ubiquitin screening in yeast, we identified RPT2 (ROOT PHOTOTROPISM 2) as a KAT1 interactor. Here, we present the results of the characterization of this interaction in yeast and plants. Importantly, we also observe increased KAT1-mediated currents in oocytes co-expressing RPT2, suggesting a functional link between the two proteins. Moreover, using stably transformed KAT1-YFP lines, we show that RPT2 is necessary for KAT1 protein accumulation in A. thaliana . Our data suggest an unexpected role for RPT2 in KAT1 post-translational regulation that may represent a novel connection between light signaling and potassium channel activity. • ROOT PHOTOTROPISM 2 was recovered in a high-throughput screen as a KAT1 interactor. • The C-terminal part of ROOT PHOTOTROPISM 2 interacts with KAT1 in yeast and plants. • ROOT PHOTOTROPISM 2 expression increases KAT1-mediated currents in Xenopus oocytes. • ROOT PHOTOTROPISM 2 is required for efficient KAT1 protein accumulation in plants.