Barker P A, Lomen-Hoerth C, Gensch E M, Meakin S O, Glass D J, Shooter E M
Department of Neurobiology, Stanford University, California 94305-5401.
J Biol Chem. 1993 Jul 15;268(20):15150-7.
The trkA receptor functions as a signal transducing receptor for nerve growth factor. In this report, we show that alternative splicing results in the production of two distinct trkA isoforms in both rats and humans. These isoforms differ by virtue of a 6-amino acid insertion in their extracellular domain, the placement of which corresponds exactly with the breakpoint found in several human trkA oncogenes. When tested in fibroblasts, the presence (trkAII) or absence (trkAI) of the 6-amino acid insert does not affect the receptor's ligand binding specificity or its ability to transduce functional signals in response to nerve growth factor. In rats and humans, trkAII is the only isoform expressed within neuronal tissues at appreciable levels whereas trkAI, the form of trkA originally cloned, appears to be expressed mainly in non-neuronal tissues.
TrkA受体作为神经生长因子的信号转导受体发挥作用。在本报告中，我们表明选择性剪接导致大鼠和人类中产生两种不同的TrkA异构体。这些异构体因其细胞外结构域中6个氨基酸的插入而有所不同，其位置与在几种人类TrkA癌基因中发现的断点完全对应。在成纤维细胞中进行测试时，6个氨基酸插入的存在（TrkAII）或不存在（TrkAI）并不影响受体的配体结合特异性或其响应神经生长因子转导功能性信号的能力。在大鼠和人类中，TrkAII是在神经组织中以可观水平表达的唯一异构体，而最初克隆的TrkA形式TrkAI似乎主要在非神经组织中表达。
