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Structure, function and regulation of the coated vesicle V-ATPase
1Department of Cellular and Molecular Physiology, Tufts University School of Medicine, Boston, MA 02111.
The Journal of Experimental Biology
|November 1, 1992
Summary
The vacuolar-H(+)-ATPase (V-ATPase) is crucial for cell transport. Its V1 and Vo domains, unlike F-type ATPases, work together to regulate vacuolar acidification.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The vacuolar-type H(+)-ATPase (V-ATPase) is essential for intracellular membrane traffic and receptor-mediated endocytosis.
- It establishes an acidic environment vital for ligand-receptor dissociation and receptor recycling.
Purpose of the Study:
- To investigate the structure and function of the V-ATPase complex.
- To elucidate the roles of specific subunits and residues in V-ATPase catalysis and proton transport.
Main Methods:
- Reassembly studies were used to analyze subunit roles within the V-ATPase complex.
- Chemical labeling identified critical residues involved in V-ATPase catalysis.
Main Results:
- The V-ATPase is a macromolecular complex (750,000 Da) with distinct V1 (peripheral, 500,000 Da) and Vo (integral, 250,000 Da) domains.
- V1 domain subunits (73, 58, 40, 34, 33 kDa) bind nucleotides; Vo domain subunits (100, 38, 19, 17 kDa) facilitate proton conduction.
- Unlike F-type ATPases, V1 and Vo domains of V-ATPase do not function independently.
Conclusions:
- The V-ATPase's V1 and Vo domains are interdependent, suggesting a unique regulatory mechanism.
- Understanding V-ATPase subunit interactions is key to regulating vacuolar acidification.