Upregulation of vacuolar H+‐translocating pyrophosphatase by phosphate starvation of Brassica napus (rapeseed) suspension cell cultures

[摘要]

The influence of phosphate (Pi) deprivation on the vacuolar H⁺-translocating pyrophosphatase (PPiase) and ATPase in tonoplast vesicles from Brassica napus suspension cells was assessed. Pi starvation significantly elevated the ratios of PPi-:ATP-dependent H⁺ translocation rate and H⁺-PPiase:H⁺-ATPase hydrolytic activities. These increases were reversed 36 h following resupply of 2.5 mM Pi to the Pi-starved cells. Immunoblotting indicated that Pi starvation also induced a two-fold increase in the amount of H⁺-PPiase protein, whereas the amount of H⁺-ATPase remained unchanged. It is proposed that H⁺-PPiase facilitates the conservation of limited ATP pools, and Pi recycling during Pi stress.

[学科分类] 生物化学/生物物理

[关键词] Phosphate starvation;Inorganic pyrophosphate;Proton pump;Vacuolar type H+-pyrophosphatase;Vacuolar type H+-ATPase;Brassica napus;+Pi and −Pi;cultured in the presence and absence of 2.5 mM KPi;respectively;PPi;inorganic pyrophosphate;PFP;PPi:fructose-6-P 1-phosphotransferase