A plant plasma-membrane H(+)-ATPase promotes yeast TORC1 activation via its carboxy-terminal tail

The Target of Rapamycin Complex 1 (TORC1) involved in coordination of cell growth and metabolism is highly conserved among eukaryotes. Yet the signals and mechanisms controlling its activity differ among taxa, according to their biological specificities. A common feature of fungal and plant cells, distinguishing them from animal cells, is that their plasma membrane contains a highly abundant H(+)-ATPase which establishes an electrochemical H(+) gradient driving active nutrient transport. We have previously reported that in yeast, nutrient-uptake-coupled H(+) influx elicits transient TORC1 activation and that the plasma-membrane H(+)-ATPase Pma1 plays an important role in this activation, involving more than just establishment of the H(+) gradient. We show here that the PMA2 H(+)-ATPase from the plant Nicotiana plumbaginifolia can substitute for Pma1 in yeast, to promote H(+)-elicited TORC1 activation. This H(+)-ATPase is highly similar to Pma1 but has a longer carboxy-terminal tail binding 14–3–3 proteins. We report that a C-terminally truncated PMA2, which remains fully active, fails to promote H(+)-elicited TORC1 activation. Activation is also impaired when binding of PMA2 to 14–3–3 s is hindered. Our results show that at least some plant plasma-membrane H(+)-ATPases share with yeast Pma1 the ability to promote TORC1 activation in yeast upon H(+)-coupled nutrient uptake.