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.
J Bioenerg Biomembr. 2013 Oct;45(5):477-90. doi: 10.1007/s10863-013-9520-1. Epub 2013 Jul 7.
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.
真菌和植物质膜 H ⁺ -ATP 酶在酵母、植物和原生动物细胞的生理学中发挥着关键作用。我们在担子菌尿囊菌中鉴定了两个编码两种质膜 H ⁺ -ATP 酶的基因，一种蛋白质与真菌（um02581）和另一种与植物（um01205）H ⁺ -ATP 酶的同一性更高。与在富含 YPD 培养基中培养的细胞相比，当细胞在含有乙醇的最低限度培养基中生长时，质子泵活性高出 5 倍，但在这两种条件下总钒酸盐敏感 ATP 酶活性相同。相比之下，在含有葡萄糖的最低限度培养基中培养的细胞中的活性比在 YPD 或乙醇中高 2 倍，这表明在尿囊菌中存在调节质膜 ATP 酶活性的机制。对在不同条件下生长的 H ⁺ -ATP 酶基因表达的分析表明，um01205（植物型）的转录表达高于 um02581（真菌型）。通过质谱分析证实了两种蛋白质的翻译。与面包酵母和植物 H ⁺ -ATP 酶不同，后者的活性分别通过短时间与葡萄糖或蔗糖孵育而增加，尿囊菌 H ⁺ -ATP 酶活性不会响应这些糖而变化。对两种尿囊菌 H ⁺ -ATP 酶的序列分析表明，缺乏经典的苏氨酸和丝氨酸残基，这些残基是酿酒酵母和拟南芥质膜 H ⁺ -ATP 酶中蛋白激酶的靶标，这表明尿囊菌酶的磷酸化发生在不同的氨基酸残基上。
