The unfolded protein response has a protective role in yeast models of classic galactosemia |
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| Authors: | Evandro A De-Souza Felipe S A Pimentel Caio M Machado Larissa S Martins Wagner S da-Silva Mónica Montero-Lomelí Claudio A Masuda |
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| Institution: | 1.Instituto de Bioquímica Médica Leopoldo de Meis, Programa de Biologia Molecular e Biotecnologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-590, Brazil.;2.Instituto de Bioquímica Médica Leopoldo de Meis, Programa de Bioquímica e Biofísica Celular, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-902, Brazil. |
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| Abstract: | Classic galactosemia is a human autosomal recessive disorder caused by mutations in the GALT gene (GAL7 in yeast), which encodes the enzyme galactose-1-phosphate uridyltransferase. Here we show that the unfolded protein response pathway is triggered by galactose in two yeast models of galactosemia: lithium-treated cells and the gal7Δ mutant. The synthesis of galactose-1-phosphate is essential to trigger the unfolded protein response under these conditions because the deletion of the galactokinase-encoding gene GAL1 completely abolishes unfolded protein response activation and galactose toxicity. Impairment of the unfolded protein response in both yeast models makes cells even more sensitive to galactose, unmasking its cytotoxic effect. These results indicate that endoplasmic reticulum stress is induced under galactosemic conditions and underscores the importance of the unfolded protein response pathway to cellular adaptation in these models of classic galactosemia.KEY WORDS: Yeast, Galactosemia, UPR, Lithium, Galactose |
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