The plasma‐membrane polyamine transporter PUT3 is regulated by the Na⁺/H⁺ antiporter SOS1 and protein kinase SOS2

Abstract

Summary In Arabidopsis, the plasma membrane transporter PUT3 is important to maintain the cellular homeostasis of polyamines and plays a role in stabilizing mRNAs of some heat‐inducible genes. The plasma membrane Na+/H+ transporter SOS1 and the protein kinase SOS2 are two salt‐tolerance determinants crucial for maintaining intracellular Na+ and K+ homeostasis. Here, we report that PUT3 genetically and physically interacts with SOS1 and SOS2, and these interactions modulate PUT3 transport activity. Overexpression of PUT3 (PUT3OE) results in hypersensitivity of the transgenic plants to polyamine and paraquat. The hypersensitivity of PUT3OE is inhibited by the sos1 and sos2 mutations, which indicates that SOS1 and SOS2 are required for PUT3 transport activity. A protein interaction assay revealed that PUT3 physically interacts with SOS1 and SOS2 in yeast and plant cells. SOS2 phosphorylates PUT3 both in vitro and in vivo. SOS1 and SOS2 synergistically activate the polyamine transport activity of PUT3, and PUT3 also modulates SOS1 activity by activating SOS2 in yeast cells. Overall, our findings suggest that both plasma‐membrane proteins PUT3 and SOS1 could form a complex with the protein kinase SOS2 in response to stress conditions and modulate the transport activity of each other through protein interactions and phosphorylation.

Phylogenetic Diversity and Physiological Roles of Plant Monovalent Cation/H+ Antiporters

“…Direct interaction with TOC34 translocon at the outer envelope membrane of chloroplasts 34) allows CBL10 to modulate Ca 2+ signals in diverse ways ( Cho et al., 2016 ). In addition, salt stress-induced SOS1A/SOS2 complex interacts, phosphorylates and activates PUT3 polyamine transporter ( Chai et al., 2020 ), leading to accumulation of polyamine in the cytosol and protecting cells from oxidative stress ( Shen et al., 2016 ). Polyamines are also potential blockers of tonoplast slow (SV) vacuolar channels ( Pottosin et al., 2014 ).…”

Lipid kinases PIP5K7 and PIP5K9 are required for polyamine‐triggered K+ efflux in Arabidopsis roots

“…The molecular mechanisms behind polyamine perception and signalling are largely unknown, though several downstream components of polyamine action have been identified, including protein kinases, transcription factors, reactive oxygen species (ROS) and Ca 2+ and K + fluxes (Takahashi et al ., 2003; Yoda, 2006; Kusano et al ., 2008b; Wu et al ., 2010; Bitrián et al ., 2012; Moschou et al ., 2012; Pál et al ., 2015; Sagor et al ., 2015; Pegg, 2016; Zarza et al ., 2019). Polyamines have also recently been linked to the perception of salt stress through SOS1 (Chai et al ., 2020). As polyamines appear to be involved in a range of plant stresses that also trigger PIP 2 responses (Tiburcio et al ., 2014; Heilmann, 2016a) and affect similar targets, including K + channels (Liu et al ., 2005; Ma et al ., 2009; Wigoda et al ., 2010), we hypothesised that polyamines are linked to the metabolism of phosphoinositides.…”

Melatonin Maintains Macrophage M1 Phenotype to Reverse LPS-stimulated Tumor Immune Tolerance

“…Based on self-healing ability, immunotherapy has been great expectation against distinct types of cancer. [32][33][34][35][36][37] Current immunotherapies targeting different cellular checkpoint controllers emerged as having either innate or acquired resistance due to the immunosuppressive tumor environment, guiding the direction of developing cancer immunotherapy. [38] The object of cancer immunotherapy is to stimulate a long-lasting immunosurveillance, maintaining the antitumor immunity.…”