Arabidopsis thaliana vacuolar TPK channels form functional K+ uptake pathways in Escherichia coli

Very few vacuolar two pore potassium channels (TPKs) have been functionally characterized. In this paper we have used complementation of K+ uptake deficient Escherichia coli mutant LB2003 to analyze the functional properties of Arabidopsis thaliana TPK family members. The four isoforms of AtTPKs were cloned and expressed in LB2003 E. coli background. The expression of channels in bacteria was analyzed by RT-PCR. Our results show that AtTPK1, AtTPK2 and AtTPK5 are restoring the LB2003 growth on low K+ media. The analysis of potassium uptake exhibited elevated level of K+ uptake in the same three types of AtTPKs transformants.