Erdmann K S, Kaiser A D, Klinz F J, Zhong J, Krautwald S, Heumann R
Department of Molecular Neurobiochemistry, Ruhr-University Bochum, Germany.
Biochem Biophys Res Commun. 1998 Aug 28;249(3):891-7. doi: 10.1006/bbrc.1998.9219.
The regulation of the density of innervation and the promotion of survival of neurons are the original effects depending on neurotrophins. Here we analyse such effects evoked by trkB tyrosine kinase in transfected PC12 cells and transfected sympathetic neurons. In order to exclude the previously described modulation of trk kinase activity by the extracellular activation of the low-affinity p75 neurotrophin receptor, we applied a chimeric receptor approach: The extracellular domain of colony-stimulating factor-1 (CSF-1) receptor was fused to the transmembrane and cytoplasmic domain of the trkB tyrosine kinase receptor, allowing its selective activation by the heterologous ligand. Protein expression and CSF-1-induced tyrosine phosphorylation of the chimeric receptor protein was demonstrated in transfected COS cells. After stable transfection into nerve growth factor (NGF)-responsive PC12 cells, CSF-1 mediated the K252a-sensitive induction of fiber outgrowth. Furthermore, we were able to show by heterologous expression of the chimeric receptor, that activation of trkB tyrosine kinase activity is sufficient to promote survival of neurotrophin deprived sympathetic neurons.
神经支配密度的调节和神经元存活的促进是神经营养因子的原始作用。在此，我们分析了转染的PC12细胞和转染的交感神经元中trkB酪氨酸激酶所引发的此类作用。为了排除先前所述的低亲和力p75神经营养因子受体的细胞外激活对trk激酶活性的调节，我们采用了嵌合受体方法：将集落刺激因子-1（CSF-1）受体的细胞外结构域与trkB酪氨酸激酶受体的跨膜和细胞质结构域融合，使其能够被异源配体选择性激活。在转染的COS细胞中证实了嵌合受体蛋白的蛋白表达及CSF-1诱导的酪氨酸磷酸化。在稳定转染至对神经生长因子（NGF）有反应的PC12细胞后，CSF-1介导了对纤维生长的K252a敏感诱导。此外，我们通过嵌合受体的异源表达表明，trkB酪氨酸激酶活性的激活足以促进神经营养因子剥夺的交感神经元的存活。
