title: The basidiomycete Ustilago maydis has two plasma membrane H⁺-ATPases related to fungi and plants.
abstract: The fungal and plant plasma membrane H⁺-ATPases play critical roles in the physiology of yeast, plant and protozoa cells. We identified two genes encoding two plasma membrane H⁺-ATPases in the basidiomycete Ustilago maydis, one protein with higher identity to fungal (um02581) and the other to plant (um01205) H⁺-ATPases. Proton pumping activity was 5-fold higher when cells were grown in minimal medium with ethanol compared to cells cultured in rich YPD medium, but total vanadate-sensitive ATPase activity was the same in both conditions. In contrast, the activity in cells cultured in minimal medium with glucose was 2-fold higher than in YPD or ethanol, implicating mechanisms for the regulation of the plasma membrane ATPase activity in U. maydis. Analysis of gene expression of the H⁺-ATPases from cells grown under different conditions, showed that the transcript expression of um01205 (plant-type) was higher than that of um02581 (fungal-type). The translation of the two proteins was confirmed by mass spectrometry analysis. Unlike baker's yeast and plant H⁺-ATPases, where the activity is increased by a short incubation with glucose or sucrose, respectively, U. maydis H⁺-ATPase activity did not change in response to these sugars. Sequence analysis of the two U. maydis H⁺-ATPases revealed the lack of canonical threonine and serine residues which are targets of protein kinases in Saccharomyces cerevisiae and Arabidopsis thaliana plasma membrane H⁺-ATPases, suggesting that phosphorylation of the U. maydis enzymes occurs at different amino acid residues.
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Miguel Hidalgo, 11340, México, D.F., México.
authors.forename: Leobarda
authors.initials: L
authors.lastname: Robles-Martínez
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Pardo
authors.forename: Manuel
authors.initials: M
authors.lastname: Miranda
authors.forename: Tavis L
authors.initials: TL
authors.lastname: Mendez
authors.forename: Macario Genaro
authors.initials: MG
authors.lastname: Matus-Ortega
authors.forename: Guillermo
authors.initials: G
authors.lastname: Mendoza-Hernández
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Guerra-Sánchez
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D013058:Mass Spectrometry; D010766:Phosphorylation; D014588:Ustilago / Q000201:enzymology*
chemical_list: D000251:Adenosine Triphosphatases