2021 年 56 巻 2 号 p. 117-121
Plants take up and translocate nutrients through transporters. Transporters which also act as sensors are called transceptors. In Arabidopsis thaliana, NRT1.1/CHL1 is known as a nitrate transceptor regulating primary nitrate responses, and IRT1 iron transporter acts as a metal transceptor to regulate degradation of itself. Here I discuss the function and regulation of a borate transceptor BOR1. BOR1 is a key transporter for boron (B) translocation and survival under B limitation in the soil. Upon sufficient-B supply, BOR1 undergoes ubiquitination and is transported to the vacuole for degradation, to avoid B toxicity. Our recent findings suggest that polyubiquitination of BOR1 relies on its conformational transitionduring the active transport cycle. In our model, BOR1 borate transceptor directly senses the B concentration and promotes its own polyubiquitination and vacuolar sorting for quick and precise maintenance of B homeostasis.