Bennett V, Baines A J, Davis J Q
J Cell Biochem. 1985;29(2):157-69. doi: 10.1002/jcb.240290210.
Brain membranes contain an actin-binding protein closely related in structure and function to erythrocyte spectrin. The proteins that attach brain spectrin to membranes are not established, but, by analogy with the erythrocyte membrane, may include ankyrin and protein 4.1. In support of this idea, proteins closely related to ankyrin and 4.1 have been purified from brain and have been demonstrated to associate with brain spectrin. Brain ankyrin binds with high affinity to the spectrin beta subunit at the midregion of spectrin tetramers. Brain ankyrin also has binding sites for the cytoplasmic domain of the erythrocyte anion channel (band 3), as well as for tubulin. Ankyrins from brain and erythrocytes have a similar domain structure with protease-resistant domains of Mr = 72,000 that contain spectrin-binding activity, and domains of Mr = 95,000 (brain ankyrin) or 90,000 (erythrocyte ankyrin) that contain binding sites for both tubulin and the anion channel. Brain ankyrin is present at about 100 pmol/mg membrane protein, or about twice the number of copies of spectrum beta chains. Brain ankyrin thus is present in sufficient amounts to attach spectrin to membranes, and it has the potential to attach microtubules to membranes as well as to interconnect microtubules with spectrin-associated actin filaments. Another spectrin-binding protein has been purified from brain membranes, and this protein cross-reacts with erythrocyte 4.1. Brain 4.1 is identical to the membrane protein synapsin, which is one of the brain's major substrates for cAMP-dependent and Ca/calmodulin-dependent protein kinases with equivalent physical properties, immunological cross-reaction, and peptide maps. Synapsin (4.1) is present at about 60 pmol/mg membrane protein, and thus is a logical candidate to regulate certain protein linkages involving spectrin.
脑膜含有一种肌动蛋白结合蛋白，其结构和功能与红细胞血影蛋白密切相关。将脑血影蛋白附着于膜上的蛋白质尚未明确，但根据与红细胞膜的类比，可能包括锚蛋白和蛋白4.1。支持这一观点的是，与锚蛋白和4.1密切相关的蛋白质已从脑中纯化出来，并已证明它们与脑血影蛋白相关联。脑锚蛋白以高亲和力与血影蛋白四聚体中部区域的血影蛋白β亚基结合。脑锚蛋白还具有与红细胞阴离子通道（带3）的细胞质结构域以及微管蛋白结合的位点。脑和红细胞中的锚蛋白具有相似的结构域结构，其抗蛋白酶结构域的分子量为72,000，具有血影蛋白结合活性，分子量为95,000（脑锚蛋白）或90,000（红细胞锚蛋白）的结构域含有微管蛋白和阴离子通道的结合位点。脑锚蛋白的含量约为100 pmol/mg膜蛋白，约为血影蛋白β链拷贝数的两倍。因此，脑锚蛋白的含量足以将血影蛋白附着于膜上，并且它有可能将微管附着于膜上，以及使微管与血影蛋白相关的肌动蛋白丝相互连接。另一种血影蛋白结合蛋白已从脑膜中纯化出来，该蛋白与红细胞4.1发生交叉反应。脑4.1与膜蛋白突触素相同，突触素是脑中依赖cAMP和Ca/钙调蛋白的蛋白激酶的主要底物之一，具有相同的物理性质、免疫交叉反应和肽图谱。突触素（4.1）的含量约为60 pmol/mg膜蛋白，因此是调节某些涉及血影蛋白的蛋白质连接的合理候选者。
