AtCCX1 transports Na+ and K+ in Pitch pastoris
Compartmentation of Na+ into vacuoles is an important way for cells to avoid the toxic effects of salt. Here, Arabidopsis AtCCX1 was studied in Pitch pastoris GS115. Yeast expressing AtCCX1 grew better in high H+ concentration medium and high salt medium than original strain and increased Na+ accumulation and decreased K+ accumulation. AtCCX1 was located in tonoplast in yeast. Transport essays were indicated by fluorescence SBFI and PBFI, respectively. Results show that AtCCX1 simultaneously participate in transports both of Na+ and K+ and the process was inhibited by H+-ATPase inhibitor vanadate. In conclusion, we suggest that AtCCX1 is an H+-dependent Na+/K+ exchanger.
Key words: AtCCX1, SBFI, PBFI, Na+ accumulation, K+ accumulation.