Sychrová H, Ramírez J, Peña A
Department of Membrane Transport, Czech Academy of Sciences, Prague, Czech Republic.
FEMS Microbiol Lett. 1999 Feb 15;171(2):167-72. doi: 10.1111/j.1574-6968.1999.tb13428.x.
The Nha1 antiporter is involved in regulation of intracellular pH in Saccharomyces cerevisiae. We report that deletion of the NHA1 gene resulted in an increase of cytoplasmic pH in cells suspended in water or acidic buffers. Addition of KCl or NaCl to exponentially growing cells lowered the internal pH but the difference between cells with or without NHA1 was maintained. Addition of KCl to starved cells resulted in much higher alkalinization of cytoplasmic pH in a strain lacking Nha1p compared to the wild-type or Nha1p-overexpressing strains. The H+/K+(Na+) exchange mechanism of Nha1p was confirmed in reconstituted plasma membrane vesicles.
Nha1反向转运蛋白参与酿酒酵母细胞内pH的调节。我们报道，NHA1基因的缺失导致悬浮于水或酸性缓冲液中的细胞胞质pH升高。向指数生长期的细胞中添加KCl或NaCl可降低细胞内pH，但有或无Nha1的细胞之间的差异仍然存在。与野生型或Nha1p过表达菌株相比，向饥饿细胞中添加KCl会导致缺乏Nha1p的菌株中细胞质pH出现更高程度的碱化。在重构的质膜囊泡中证实了Nha1p的H⁺/K⁺(Na⁺)交换机制。
