Yoshimura Shige H, Takeyasu Kunio
Graduate School of Biostudies, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Japan.
Ann N Y Acad Sci. 2003 Apr;986:378-81. doi: 10.1111/j.1749-6632.2003.tb07217.x.
The cell-surface expression of the Na(+)/K(+)-ATPase is tightly regulated at the ER/Golgi transit level. The assembly of the alpha- and beta-subunits is a prerequisite for the maturation of the enzyme and its exit from the ER. At present, the fate of the functional ATPase, once it reaches the plasma membrane, is obscure, although endocytosis, recycling, and degradation in the lysosome are known to be involved. In this study, we shall demonstrate the differential degradation of the Na(+)/K(+)-ATPase subunits in the plasma membrane: that is, lysosomal degradation of alpha-subunits and proteasomal degradation of beta-subunits, and propose the possibility of the subunit dissociation in the plasma membrane.
钠钾ATP酶的细胞表面表达在从内质网/高尔基体转运水平受到严格调控。α亚基和β亚基的组装是该酶成熟及其从内质网输出的前提条件。目前，功能性ATP酶一旦到达质膜后的命运尚不清楚，尽管已知其涉及内吞作用、再循环以及在溶酶体中的降解。在本研究中，我们将证明质膜中钠钾ATP酶亚基的差异降解：即α亚基的溶酶体降解和β亚基的蛋白酶体降解，并提出亚基在质膜中解离的可能性。
