Kim H, Jensen C G, Rebhun L I
Ann N Y Acad Sci. 1986;466:218-39. doi: 10.1111/j.1749-6632.1986.tb38396.x.
We have presented data that indicate that MAP-2 associates with brain microtubules at nonrandomly distributed sites, whose distribution on the microtubule polymer can best be described by the 12-dimer MAP superlattice originally described by Amos; because of the additional spacings, however, between MAP-2 projections observed on MAP-2-saturated microtubules, we suggest that the 6-dimer MAP superlattice, or what we will call the double Amos superlattice, more completely specifies the total set of MAP-binding sites on cytoplasmic microtubules. Second, we have shown that brain microtubules reassembled in vitro contain a heterogeneous population of MAP-binding sites, which differ in their affinities for the two MAPs, MAP-2 and tau. Third, we have shown that microtubule populations that differ in their MAP content have subtle, but detectable differences in their tubulin isotype composition. Based on all the data presented here, we have presented the idea of a nonrandom distribution of tubulin isotypes within a microtubule as a means by which a cell could specify both the identity and the distribution of MAP-binding sites.
我们已展示的数据表明，微管相关蛋白2（MAP - 2）在非随机分布的位点与脑微管结合，其在微管聚合物上的分布用最初由阿莫斯描述的12聚体MAP超晶格来描述最为合适；然而，由于在MAP - 2饱和微管上观察到的MAP - 2投影之间存在额外间距，我们认为6聚体MAP超晶格，或者我们将其称为双阿莫斯超晶格，能更完整地确定细胞质微管上MAP结合位点的总体集合。其次，我们已表明体外重新组装的脑微管包含不同类型的MAP结合位点，这些位点对两种微管相关蛋白，即MAP - 2和微管tau蛋白的亲和力不同。第三，我们已表明，MAP含量不同的微管群体在微管蛋白异构体组成上存在细微但可检测到的差异。基于此处展示的所有数据，我们提出了微管内微管蛋白异构体非随机分布的观点，作为细胞确定MAP结合位点的身份和分布的一种方式。
