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The amino-terminal domain of the E subunit of vacuolar H(+)-ATPase (V-ATPase) interacts with the H subunit and is required for V-ATPase function.

Vacuolar H(+)-ATPases (V-ATPases) are highly conserved proton pumps that couple hydrolysis of cytosolic ATP to proton transport out of the cytosol. Although it is generally believed that V-ATPases transport protons by a rotary catalytic mechanism analogous to that used by F(1)F(0)-ATPases, the structure and subunit composition of the central or peripheral stalk of the multisubunit complex are not well understood. We searched for proteins that bind to the E subunit of V-ATPase using the yeast two-hybrid assay and identified the H subunit as an interacting partner. Physical association between the E and H subunits of V-ATPase was confirmed in vitro by precipitation assays. Deletion mapping analysis revealed that a 78-amino acid fragment at the amino terminus of the E subunit was sufficient for binding to the H subunit. Expression of the amino-terminal fragments of the E subunits from human and yeast as dominant-negative mutants resulted in dramatic decreases in bafilomycin A(1)-sensitive ATP hydrolysis and proton transport activities of V-ATPase. Our data demonstrate the physiological significance of the interaction between the E and H subunits of V-ATPase and extend previous studies on the arrangement of subunits on the peripheral stalk of V-ATPase.

Pubmed ID: 12163484


  • Lu M
  • Vergara S
  • Zhang L
  • Holliday LS
  • Aris J
  • Gluck SL


The Journal of biological chemistry

Publication Data

October 11, 2002

Associated Grants

  • Agency: NIDDK NIH HHS, Id: R01 DK38848
  • Agency: NIDDK NIH HHS, Id: R01 DK54362

Mesh Terms

  • Adenosine Triphosphate
  • Amino Acid Sequence
  • Anti-Bacterial Agents
  • Enzyme Inhibitors
  • Humans
  • Macrolides
  • Molecular Sequence Data
  • Protein Binding
  • Protein Structure, Tertiary
  • Protein Subunits
  • Protons
  • Recombinant Fusion Proteins
  • Sequence Alignment
  • Two-Hybrid System Techniques
  • Vacuolar Proton-Translocating ATPases
  • Yeasts