Interaction of NT-4 and BDNF with gp145 super(trkb) receptor: Effect on cellular metabolism

• Published in: Journal of neuroscience methods 1997-04, Vol.72 (2), p.167-174
• Main Authors: Hopkins, MA, Rosser, M P, Fernandes, P B, Bursuker, I
• Format: Article
• Language: English
• ISSN: 0165-0270

In the present study a silicon microphysiometer (Cytosensor registered ) was applied in investigating interactions of gp145 super(trkb), a member of the tyrosine kinase receptor family, with different neurotrophic factors. NIH-3Td cells transfected with gp145 super(trkb) receptors (NIH3T3/trkB cells) were utilized in the studies. Treatment with brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4) and neurotrophin-3 (NT-3) induced changes in the metabolic rate of NIH3T3/trkB cells. In contrast, no response was observed with nerve growth factor (NGF). The effects of NT-4 and BDNF on NIH3T3/trkB cells were receptor-specific in that they did not induce metabolic rate changes in wild type NIH3T3 cells or cells transfected with either gp140 super(trka) (TrkA) or gp145 super(trkc) (TrkC) receptors. In contrast, NT-3 induced metabolic rate changes in cells transfected with each of the three different Trk receptors. The activity of NT-4 was significantly higher than that of BDNF. K252a, a protein kinase inhibitor, reduced the NT-4- and BDNF-induced response of the NIH3T3/trkB cells. This suggests that the NT-4 and BDNF-induced metabolic rate changes are associated with autophosphorylation of the tyrosine protein kinase residues. This hypothesis is further supported by results of western blot analysis. The results show that interactions of Trk receptors with neurotrophic factors result in metabolic changes in cells expressing the receptors.