Lucini C, de Girolamo P, Lamanna C, Botte V, Vega J A, Castaldo L
Università di Napoli Federico II, Dipartimento di Strutture, Funzioni e Tecnologie Biologiche, Via Veterinaria 1, 80137 Naples, Italy.
Cell Tissue Res. 2001 Mar;303(3):345-50. doi: 10.1007/s004410000342.
The tyrosine kinase proteins (Trk), encoded by the trk family of proto-oncogenes, mediate, in mammals, the action of neurotrophins, a family of growth factors acting on the development and maintenance of the nervous system. Neurotrophins and their specific receptors, TrkA, TrkB and TrkC, seem to be phylogenetically well preserved but, in reptiles, data regarding the occurrence of Trk-like proteins are very scarce, especially in non-nervous organs. Western blot analysis demonstrated that the lizard gut contains TrkA- and TrkC-like, but not TrkB-like, proteins. Consistently, TrkA- and TrkC-like immunoreactivity were both observed in neurons of the anterior intestine, whereas endocrine cells of the stomach and anterior intestine only displayed TrkA-like immunoreactivity. These results demonstrate for the first time the occurrence of Trk-like proteins in non-neuronal tissues of reptilians and provide further evidence for the evolutionary preservation of the molecular mass and cell distribution of Trk neurotrophin receptor-like proteins in the gut of vertebrates.
原癌基因trk家族编码的酪氨酸激酶蛋白（Trk）在哺乳动物中介导神经营养因子的作用，神经营养因子是一类作用于神经系统发育和维持的生长因子。神经营养因子及其特异性受体TrkA、TrkB和TrkC在系统发育上似乎保存良好，但在爬行动物中，关于Trk样蛋白存在情况的数据非常稀少，尤其是在非神经器官中。蛋白质免疫印迹分析表明，蜥蜴肠道中含有TrkA样和TrkC样蛋白，但不含TrkB样蛋白。一致地，在前肠神经元中均观察到TrkA样和TrkC样免疫反应性，而胃和前肠的内分泌细胞仅显示TrkA样免疫反应性。这些结果首次证明了Trk样蛋白在爬行动物非神经组织中的存在，并为Trk神经营养因子受体样蛋白在脊椎动物肠道中的分子量和细胞分布的进化保守性提供了进一步证据。
