Reversible disassembly of the yeast V-ATPase revisited under in vivo conditions.

Primary active proton transport by eukaryotic V-ATPases (vacuolar ATPases) is regulated via the reversible disassembly of the V1Vo holoenzyme into its peripheral catalytic V1 complex and its membrane-bound proton-translocating Vo complex. This nutrient-dependent phenomenon had been first detected in the midgut epithelium of non-feeding moulting tobacco hornworms (Manduca sexta) and in glucose-deprived yeast cells (Saccharomyces cerevisiae). Since reversible disassembly to date had been investigated mostly in vitro, we wanted to test this phenomenon under in vivo conditions.

Vacuolar H(+)-ATPases: intra- and intermolecular interactions.

V-ATPases in eukaryotes are heteromultimeric, H(+)-transporting proteins. They are localized in a multitude of different membranes and energize many different transport processes. Unique features of V-ATPases are, on the one hand, their ability to regulate enzymatic and ion transporting activity by the reversible dissociation of the catalytic V(1) complex from the membrane bound proton translocating V(0) complex and, on the other hand, their high sensitivity to specific macrolides such as bafilomycin and concanamycin from streptomycetes or archazolid and apicularen from myxomycetes.