Seventeen a-subunit isoforms of paramecium V-ATPase provide high specialization in localization and function. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Molecular Biology of the Cell Année : 2006

Seventeen a-subunit isoforms of paramecium V-ATPase provide high specialization in localization and function.

Thomas Wassmer
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Roland Kissmehl
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Jean Cohen
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Résumé

In the Paramecium tetraurelia genome, 17 genes encoding the 100-kDa-subunit (a-subunit) of the vacuolar-proton-ATPase were identified, representing by far the largest number of a-subunit genes encountered in any organism investigated so far. They group into nine clusters, eight pairs with >82% amino acid identity and one single gene. Green fluorescent protein-tagging of representatives of the nine clusters revealed highly specific targeting to at least seven different compartments, among them dense core secretory vesicles (trichocysts), the contractile vacuole complex, and phagosomes. RNA interference for two pairs confirmed their functional specialization in their target compartments: silencing of the trichocyst-specific form affected this secretory pathway, whereas silencing of the contractile vacuole complex-specific form altered organelle structure and functioning. The construction of chimeras between selected a-subunits surprisingly revealed the targeting signal to be located in the C terminus of the protein, in contrast with the N-terminal targeting signal of the a-subunit in yeast. Interestingly, some chimeras provoked deleterious effects, locally in their target compartment, or remotely, in the compartment whose specific a-subunit N terminus was used in the chimera.

Dates et versions

hal-00133127 , version 1 (23-02-2007)

Identifiants

Citer

Thomas Wassmer, Roland Kissmehl, Jean Cohen, Helmut Plattner. Seventeen a-subunit isoforms of paramecium V-ATPase provide high specialization in localization and function.. Molecular Biology of the Cell, 2006, 17 (2), pp.917-30. ⟨10.1091/mbc.E05-06-0511⟩. ⟨hal-00133127⟩
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