ABSTRACT
A typical plant cell expresses four ATP-fueled proton pumps (H+-ATPases), each one targeted to a specific cellular membrane. The F0F1 and CF0CF1 H
+-ATPases, present in the mitochondrial inner membrane and the thylakoid membrane, respectively, operate under physiological conditions to synthesize ATP at the expense of H+ gradients. Vacuolar H+-ATPase and plasma membrane H+-ATPase, on the other hand, generate H+ gradients at the expense of ATP. The plant plasma membrane H+-ATPase has been extensively discussed in a number of recent reviews [1-5]. In the present chapter we give an overview of recent structural and functional aspects of the plasma membrane H+- ATPase, including its regulation and its role in intra-and extracellular pH regulation.
