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Liu M, et al.  (2005) Structural and functional separation of the N- and C-terminal domains of the yeast V-ATPase subunit H. J Biol Chem 280(44):36978-85

Abstract: The H subunit of the yeast V-ATPase is an extended structure with two relatively independent domains, an N-terminal domain consisting of amino acids 1-348 and a C-terminal domain consisting of amino acids 352-478 (Sagermann et al. (2001), Proc. Natl. Acad. Sci. 98:7134). We have expressed these two domains independently and together in a yeast strain lacking the H subunit (vma13 mutant). The N-terminal domain partially complements the growth defects of the mutant and supports approximately 25% of the wild-type Mg(2+)-dependent ATPase activity in isolated vacuolar vesicles, but surprisingly, this activity is both largely concanamycin-insensitive and uncoupled from proton transport. The C-terminal domain does not complement the growth defects, and supports no ATP hydrolysis or proton transport, even though it is recruited to the vacuolar membrane. Expression of both domains in a vma13 strain gives better complementation than either fragment alone, and results in higher concanamycin-sensitive ATPase activity and ATP-driven proton pumping than the N-terminal domain alone. Thus, the two domains make complementary contributions to structural and functional coupling of the peripheral V1 and membrane Vo sectors of the V-ATPase, but this coupling does not require that they be joined covalently. The N-terminal domain alone is sufficient for activation of ATP hydrolysis in V1, but the C-terminal domain is essential for proper communication between the V1 and Vo sectors.

Status: Published

Type: Journal Article

PubMed ID: 16141210

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Liu M Tarsio M Charsky CM Kane PM Papers in SGD Colleagues in SGD PubMed Google Scholar

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