Pestov N B, Korneenko T V, Zhao H, Adams G, Shakhparonov M I, Modyanov N N
Department of Pharmacology, Medical College of Ohio, Toledo, Ohio 43614, USA.
Biochem Biophys Res Commun. 2000 Oct 22;277(2):430-5. doi: 10.1006/bbrc.2000.3692.
Recently we have identified mRNA encoding a hitherto unknown mammalian X,K-ATPase beta-subunit expressed predominantly in muscle tissue (Pestov, N. B. et al. (1999) FEBS Lett. 456, 243-248). Here we demonstrate the existence of the predicted protein, designated as beta(m) (beta(muscle)), in human adult skeletal muscle membranes using immunoblotting with beta(m)-specific antibodies generated against recombinant polypeptide formed by extramembrane beta(m) domains. The electrophoretic mobility of beta(m) was shown to be abnormally low due to the presence of Glu-rich sequences. In contrast to mature forms of other known X,K-ATPase beta-subunits, carbohydrate moiety of beta(m) is sensitive to endoglycosidase H and appears to be composed of short high-mannose or hybrid N-glycans. This finding argues in favor of an intracellular location of beta(m) in human skeletal muscle.
最近，我们鉴定出了一种信使核糖核酸（mRNA），它编码一种迄今未知的哺乳动物X，K - 三磷酸腺苷酶（X，K - ATPase）β亚基，该亚基主要在肌肉组织中表达（佩斯托夫，N. B. 等人（1999年）《欧洲生物化学学会联合会快报》456，243 - 248）。在此，我们利用针对由膜外β(m)结构域形成的重组多肽产生的β(m)特异性抗体进行免疫印迹，证实在成人人类骨骼肌膜中存在预测的蛋白质，命名为β(m)（β(肌肉)）。由于存在富含谷氨酸的序列，β(m)的电泳迁移率显示异常低。与其他已知的X，K - ATPaseβ亚基的成熟形式不同，β(m)的碳水化合物部分对内切糖苷酶H敏感，并且似乎由短的高甘露糖型或杂合N - 聚糖组成。这一发现支持β(m)在人类骨骼肌细胞内定位的观点。
