Vacuolar H+-ATPase domains are transported separately in axons and assemble in Torpedo nerve endings.
Torpedo electric organ synaptosomes possess a typical vacuolar H+-ATPase (V-ATPase), inhibited by concanamycin A and insensitive to vanadate, made of the association of a catalytic soluble sector V1 to a membrane domain V0. In the electric nerves, the 57-kDa subunit B of the V1 sector was transported to the nerve endings by the slow axonal flow and did not accumulate upstream from an axonal block. In contrast, a 500% accumulation of the 15-kDa subunit c of the V0 membrane domain was observed, demonstrating that this subunit is conveyed by the fast axonal anterograde transport. After velocity sedimentation of solubilized nerve proteins, the 57- and 15-kDa subunits were recovered in different complexes corresponding, respectively, to the V1 and V0 domains. No fully assembled V-ATPase was detected. It is concluded that V1 and V0 domains of V-ATPase are transported separately in axons, at different rates, and that they only associate once arrived in nerve endings to form the active V-ATPase.
Morel
N
N
Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, Gif-sur-Yvette, France.
Gérard
V
V
Shiff
G
G
D000818:Animals; D001370:Axonal Transport / Q000502:physiology*; D001369:Axons / Q000378:metabolism*; D004557:Electric Organ / Q000201:enzymology; D009411:Nerve Endings / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017494:Proton Pumps / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D013574:Synaptosomes / Q000201:enzymology; D014101:Torpedo; D025262:Vacuolar Proton-Translocating ATPases; D014617:Vacuoles / Q000201:enzymology*
D017494:Proton Pumps; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases