Vladimirova N M, Murav'eva T I, Ovchinnikova T V, Potapenko N A, Khodova O M
Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.
Membr Cell Biol. 1998;12(3):435-9.
Active preparations of Na+,K(+)-ATPase containing three types of catalytic isoforms were isolated from the bovine brain to study the structure and function of the sodium pump. Na+,K(+)-ATPase from the brain grey matter was found to have a biphasic kinetics with respect to ouabain inhibition and to consist of a set of isozymes with subunit composition of alpha 1 beta 1, alpha 2 beta m and alpha 3 beta m (where m = 1 and/or 2). The alpha 1 beta 1 form clearly dominated. For the first time, glycosylation of the beta 1-subunit of the alpha 1 beta 1-type isozymes isolated from the kidney and brain was shown to be different. Na+,K(+)-ATPase from the brain stem and axolemma consisted mainly of a mixture of alpha 2 beta 1 and alpha 3 beta 1 isozymes having identical ouabain inhibition constants. In epithelial and arterial smooth muscle cells, where the plasma membrane is divided into functionally and biochemically distinct domains, the polarized distribution of Na+,K(+)-ATPase is maintained through interactions with the membrane cytoskeleton proteins ankyrin and spectrin (Nelson and Hammerton, 1989; Lee et al., 1996). We were the first to show the presence of the cytoskeleton protein tubulin (beta 5-isoform) and glyceraldehyde-3-phosphate dehydrogenase in a high-molecular-weight complex with Na+,K(+)-ATPase in brain stem neuron cells containing alpha 2 beta 1 and alpha 3 beta 1 isozymes. Consequently, the influence of not only subunit composition, but also of glycan and cytoskeleton structures and other plasma membrane-associated proteins on the functional properties of Na+,K(+)-ATPase isozymes is evident.
从牛脑中分离出含有三种催化同工型的钠钾ATP酶活性制剂，以研究钠泵的结构和功能。发现来自脑灰质的钠钾ATP酶对哇巴因抑制具有双相动力学，并且由一组亚基组成为α1β1、α2βm和α3βm（其中m = 1和/或2）的同工酶组成。α1β1形式明显占主导。首次表明，从肾脏和脑中分离出的α1β1型同工酶的β1亚基的糖基化是不同的。来自脑干和轴膜的钠钾ATP酶主要由具有相同哇巴因抑制常数的α2β1和α3β1同工酶混合物组成。在质膜分为功能和生化上不同区域的上皮细胞和动脉平滑肌细胞中，钠钾ATP酶的极化分布通过与膜细胞骨架蛋白锚蛋白和血影蛋白的相互作用得以维持（纳尔逊和哈默顿，1989；李等人，1996）。我们首次在含有α2β1和α3β1同工酶的脑干神经元细胞中，证明细胞骨架蛋白微管蛋白（β5同工型）和甘油醛-3-磷酸脱氢酶与钠钾ATP酶存在于高分子量复合物中。因此，不仅亚基组成，而且聚糖、细胞骨架结构和其他质膜相关蛋白对钠钾ATP酶同工型功能特性的影响是显而易见的。
