PDF(Pubmed)
Abstract：
The Na,K-ATPase is an α-β heterodimer. It is well known that the Na,K-ATPase β subunit is required for the biosynthesis and trafficking of the α subunit to the plasma membrane. During investigation of properties of human ATP1A3 mutations in 293 cells, we observed a reciprocal loss of endogenous ATP1A1 when expressing ATP1A3. Scattered reports going back as far as 1991 have shown that experimental expression of one subunit can result in reduction in another, suggesting that the total amount is strictly limited. It seems logical that either α or β subunit should be rate-limiting for assembly and functional expression. Here, we present evidence that neither α nor β may be limiting and that there is another level of control that limits the amount of Na,K-ATPase to physiological levels. We propose that α subunits compete for something specific, like a private chaperone, required to finalize their biosynthesis or to prevent their degradation in the endoplasmic reticulum.
摘要：
Na,K-ATP酶是α-β异二聚体。众所周知，Na，K-ATP酶β亚基是α亚基生物合成和运输到质膜所必需的。在研究293细胞中人类ATP1A3突变的特性期间，当表达ATP1A3时，我们观察到内源性ATP1A1的相互损失。1991年的零星报道表明，一个亚基的实验表达可以导致另一个亚基的减少，这表明总量是严格限制的。似乎合乎逻辑的是，α或β亚基应为组装和功能表达的限速。这里,我们提供的证据表明，α和β都不是限制性的，并且有另一个水平的控制限制了Na的量，K-ATP酶达到生理水平。我们建议α亚基竞争特定的东西，像一个私人监护人，需要完成它们的生物合成或防止它们在内质网中的降解。
