Carlson S S, Caroni P, Kelly R B
J Cell Biol. 1986 Aug;103(2):509-20. doi: 10.1083/jcb.103.2.509.
The nerve terminal and the postsynaptic receptor-containing membranes of the electric organ are both linked to the basal lamina that runs between them. We have identified an extracellular matrix protein whose physical properties suggest it anchors the nerve terminal to the basal lamina. The protein was identified because it shares an epitope with a proteoglycan component of electric organ synaptic vesicles. It too behaves like a proteoglycan. It is solubilized with difficulty from extracellular matrix fractions, elutes from DEAE Sephacel at pH 4.9 only at high ionic strength, and binds to a laminin affinity column from which it can be eluted with heparin. Under denaturing conditions it sediments rapidly and has a large excluded volume although it can be included in Sephacryl S-1000 columns. This large, highly charged extracellular matrix molecule can be readily reconstituted into liposomes consistent with the presence of a hydrophobic tail. By immunoelectron microscopy the antigen is found both in synaptic vesicles and on the plasma membrane of the nerve terminal. Since this is the first protein described that links the nerve terminal membrane to the extracellular matrix, we propose calling it terminal anchorage protein one (TAP-1).
神经末梢和电器官中含有突触后受体的膜都与它们之间的基膜相连。我们鉴定出一种细胞外基质蛋白，其物理性质表明它将神经末梢锚定在基膜上。该蛋白是因为它与电器官突触小泡的一种蛋白聚糖成分共享一个表位而被鉴定出来的。它的行为也像一种蛋白聚糖。它很难从细胞外基质组分中溶解出来，仅在高离子强度下于pH 4.9从DEAE琼脂糖凝胶上洗脱下来，并且能与层粘连蛋白亲和柱结合，可用肝素将其从柱上洗脱下来。在变性条件下它沉降迅速且具有很大的排阻体积，尽管它能被纳入Sephacryl S - 1000柱中。这种大的、高度带电的细胞外基质分子能够很容易地重组成脂质体，这与存在疏水尾相一致。通过免疫电子显微镜观察，该抗原在突触小泡和神经末梢的质膜上均有发现。由于这是所描述的第一种将神经末梢膜与细胞外基质连接起来的蛋白，我们建议将其命名为末梢锚定蛋白1（TAP - 1）。
