Schmidt J W, Catterall W A
Cell. 1986 Aug 1;46(3):437-44. doi: 10.1016/0092-8674(86)90664-1.
The sodium channel from rat brain is a complex of alpha (260 kd), beta 1 (36 kd), and beta 2 (33 kd) subunits. The alpha and beta 2 subunits are linked by disulfide bonds. The earliest biosynthetic precursor of the alpha subunit is a 203 kd core polypeptide with sufficient high-mannose carbohydrate chains to increase its apparent size to 224 kd. It is processed to 224 kd and 249 kd precursor forms containing complex carbohydrate chains before it achieves the mature size of 260 kd. Most newly synthesized alpha subunits are not disulfide-linked to beta 2 subunits, but remain as a metabolically stable pool of intracellular subunits. alpha subunits disulfide-linked to beta 2 are found preferentially at the cell surface. A possible role for this intracellular pool as a rate-limiting step in the regulation of the cell surface density and localization of sodium channels in developing neurons is proposed.
大鼠脑钠通道是由α（260kd）、β1（36kd）和β2（33kd）亚基组成的复合体。α亚基和β2亚基通过二硫键相连。α亚基最早的生物合成前体是一个203kd的核心多肽，其带有足够多的高甘露糖碳水化合物链，使其表观大小增加到224kd。在达到260kd的成熟大小之前，它会被加工成含有复合碳水化合物链的224kd和249kd前体形式。大多数新合成的α亚基并不通过二硫键与β2亚基相连，而是作为细胞内亚基的代谢稳定池存在。与β2通过二硫键相连的α亚基优先出现在细胞表面。有人提出，这个细胞内池可能作为发育中神经元钠通道细胞表面密度和定位调节中的限速步骤发挥作用。
