Edgar D, Timpl R, Thoenen H
EMBO J. 1984 Jul;3(7):1463-8. doi: 10.1002/j.1460-2075.1984.tb01997.x.
The survival of cultured chick sympathetic neurons and the outgrowth of neurites were stimulated by the basement membrane protein laminin coated onto polyornithine culture substrates. The survival-potentiating activity was dependent on the presence of nerve growth factor. Both effects of laminin could be completely inhibited by affinity-purified antibodies against laminin fragment 3, the product of a limited proteolysis that corresponds to the heparin-binding globular domain at the end of the long arm of the laminin molecule. Antibodies against other laminin fragments were inactive, including those against previously determined cell-binding domains. A large laminin fragment, E8, was produced by brief elastase digestion and shown to consist of fragment 3 and an adjacent rod-like structure. Although lacking the cell binding domains, fragment E8 potentiated both neuronal survival and neurite outgrowth, and these effects could be blocked by antibodies against fragment 3. Weak survival and neurite potentiating activity was also detected in another fragment corresponding to the short arms of laminin, but as these effects were not inhibited by any of the antibodies tested they probably arose de novo during proteolysis. The heparin-binding domain of laminin is therefore responsible for its effects on neurons.
包被在聚鸟氨酸培养底物上的基底膜蛋白层粘连蛋白，可刺激培养的鸡交感神经元存活及神经突生长。其存活增强活性依赖于神经生长因子的存在。层粘连蛋白的这两种作用均可被针对层粘连蛋白片段3的亲和纯化抗体完全抑制，片段3是有限蛋白酶解的产物，对应于层粘连蛋白分子长臂末端的肝素结合球状结构域。针对其他层粘连蛋白片段的抗体无活性，包括针对先前确定的细胞结合结构域的抗体。通过短暂的弹性蛋白酶消化产生了一个大片层粘连蛋白片段E8，它由片段3和相邻的杆状结构组成。尽管片段E8缺乏细胞结合结构域，但它能增强神经元存活和神经突生长，且这些作用可被针对片段3的抗体阻断。在另一个对应于层粘连蛋白短臂的片段中也检测到较弱的存活和神经突增强活性，但由于这些作用未被所测试的任何抗体抑制，它们可能是在蛋白酶解过程中重新产生的。因此，层粘连蛋白的肝素结合结构域负责其对神经元的作用。
