PIN FORMED 2 modulates the transport of arsenite in Arabidopsis thaliana (Plant Comms.)

PIN FORMED (PIN) proteins are known for their directional auxin transport capacity. Ashraf et al. found that auxin transporter PINs have sequence similarity to bacterial arsenite transporter arsB, yeast Saccharomyces cerevisiae arsenite transporter SsAcr3, and arsenic hyperaccumulator fern Pteris vittata transporter PvAcr3, indicating that AtPIN2 is a possible arsenite efflux carrier. The authors found that arsenite specifically targets PIN2 protein trafficking and consequently alters auxin homeostasis. They additionally used radioactive arsenite and X-ray fluorescence imaging (XFI) coupled with X-ray absorption spectroscopy (XAS) to demonstrate in planta arsenite accumulation in the root tip in the absence of PIN2. Therefore, based on plant physiology, molecular and cellular biology, synchrotron imaging and radio-arsenite for transport assays, the authors demonstrated that the auxin transporter PIN2 also functions as an arsenite transporter. (Summary by Arif Ashraf) Plant Comms. 10.1016/j.xplc.2019.100009