The H Subunit (Vma13p) of the Yeast V-ATPase Inhibits the ATPase Activity of Cytosolic V1 Complexes*

@article{Parra2000TheHS,
  title={The H Subunit (Vma13p) of the Yeast V-ATPase Inhibits the ATPase Activity of Cytosolic V1 Complexes*},
  author={Karlett J Parra and K L Keenan and Patricia M. Kane},
  journal={The Journal of Biological Chemistry},
  year={2000},
  volume={275},
  pages={21761 - 21767}
}
V-ATPases are composed of a peripheral complex containing the ATP-binding sites, the V1 sector, attached to a membrane complex containing the proton pore, the Vo sector. In vivo, free, inactive V1 and Vo sectors exist in dynamic equilibrium with fully assembled, active V1 Vo complexes, and this equilibrium can be perturbed by changes in carbon source. Free V1 complexes were isolated from the cytosol of wild-type yeast cells and mutant strains lacking Vo subunit c (Vma3p) or V1 subunit H (Vma13p… 
Novel Vacuolar H+-ATPase Complexes Resulting from Overproduction of Vma5p and Vma13p*
TLDR
In the absence of an intact V0 sector, overproduction of Vma5p and Vma13p had a more detrimental effect on growth than their deletion, and this association with cytosolic V1complexes may cause the lethality.
Mutational Analysis of Subunit G (Vma10p) of the Yeast Vacuolar H+-ATPase*
TLDR
The results indicate that, although the N-terminal half of the G subunit is essential for V-ATPase activity, either this region is not a rigid helix or the presence of a continuous, conserved face of the helix is not essential.
Function and Subunit Interactions of the N-terminal Domain of Subunit a (Vph1p) of the Yeast V-ATPase*
TLDR
Results suggest that a localized region of the N-terminal domain is important in anchoring the peripheral stator in V1V0, suggesting that in vivo dissociation of the V-ATPase generates a V0 domain that does not passively conduct protons.
Coordinated conformational changes in the V1 complex during V-ATPase reversible dissociation
TLDR
CryoEM of yeast V-ATPase was used to determine structures of the intact enzyme, the dissociated but complete V1 complex, and the V1complex lacking sub unit C, suggesting how RAVE could reassemble V1 and VO by recruiting subunit C.
Role of the H subunit C-terminal domain in the assembly of the vacuolar H+-ATPase
TLDR
Using biolayer interferometry and biochemical analysis, it is shown that selective disruption of HCT’s binding site on V1 allows in vitro assembly of a structurally and functionally coupled V-ATPase complex.
Mutational Analysis of the Subunit C (Vma5p) of the Yeast Vacuolar H+-ATPase*
TLDR
Surprisingly, three mutations greatly decrease the stability of the V-ATPase in vitro but increase its k cat for ATP hydrolysis and proton transport by at least 3-fold; the peripheral stalk of V- ATPases must balance the stability essential for productive catalysis with the dynamic instability involved in regulation; these three mutations may perturb that balance.
Subunit H of the Vacuolar (H+) ATPase Inhibits ATP Hydrolysis by the Free V1 Domain by Interaction with the Rotary Subunit F*
TLDR
Cysteine-mediated cross-linking studies indicate that subunits H and F are proximal in free V1, supporting the hypothesis that subunit H inhibitsfree V1 by bridging the rotary and stator domains.
Subunit Interactions and Requirements for Inhibition of the Yeast V1-ATPase*
TLDR
It is proposed that upon disassembly, the H subunit undergoes a conformational change that inhibits V1-ATPase activity and precludes V0 interactions.
Mutational Analysis of the Stator Subunit E of the Yeast V-ATPase*
TLDR
Results indicated communication between subunit E and the catalytic sites at the A3B3 hexamer and suggest potential regulatory roles for the carboxyl end of subunits E within the V-ATPase complex.
MgATP hydrolysis destabilizes the interaction between subunit H and yeast V1-ATPase, highlighting H's role in V-ATPase regulation by reversible disassembly
TLDR
The observation that H binding is affected by MgATP hydrolysis in V1 points to H's role in the mechanism of reversible disassembly, suggesting an interplay between MgADP inhibition and subunit H.
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