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Cell cycle phase-specific surface expression of nerve growth factor receptors TrkA and p75(NTR)
J L Urdiales1, E Becker, M Andrieu
1Laboratoire de Biologie Moléculaire et Cellulaire, Unité Mixte de Recherche 49, Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, 69364 Lyon Cedex 07, France.
Abstract:
Expression of the nerve growth factor (NGF) receptors TrkA and p75(NTR) was found to vary at the surface of PC12 cells in a cell cycle phase-specific manner. This was evidenced by using flow cytometric and microscopic analysis of cell populations labeled with antibodies to the extracellular domains of both receptors. Differential expression of these receptors also was evidenced by biotinylation of surface proteins and Western analysis, using antibodies specific for the extracellular domains of TrkA and p75(NTR). TrkA is expressed most strongly at the cell surface in M and early G1 phases, whereas p75(NTR) is expressed mainly in late G1, S, and G2 phases. This expression reflects the molecular and cellular responses to NGF in specific phases of the cell cycle; in the G1 phase NGF elicits both the anti-mitogenic effect, i.e., inhibition of the G1 to S transition, and the differentiation response whereas a survival effect is provoked elsewhere in the cell cycle. A model is proposed relating these responses to the surface expression of the two receptors. These observations open the way for novel approaches to the investigation of the mechanism of NGF signal transduction.
Insights
Nerve growth factor (NGF) receptors TrkA and p75(NTR) show cell cycle-specific surface expression in PC12 cells. This differential expression influences NGF
Area of Science:
- Cell Biology
- Neuroscience
- Molecular Biology
Background:
- Nerve growth factor (NGF) is crucial for neuronal development and survival.
- NGF exerts its effects through TrkA and p75(NTR) receptors.
- The cell cycle regulation of these receptors is not fully understood.
Purpose of the Study:
- To investigate the cell cycle-dependent surface expression of TrkA and p75(NTR) receptors in PC12 cells.
- To correlate receptor expression patterns with specific cellular responses to NGF.
- To propose a model for NGF signal transduction based on receptor dynamics.
Main Methods:
- Flow cytometry and microscopic analysis of antibody-labeled PC12 cells.
- Biotinylation of surface proteins followed by Western blot analysis.
- Antibody-specific detection of extracellular receptor domains.
Main Results:
- TrkA receptor surface expression peaks during M and early G1 cell cycle phases.
- p75(NTR) receptor surface expression is prominent in late G1, S, and G2 phases.
- NGF elicits anti-mitogenic and differentiation effects in G1, and survival effects in other phases.
Conclusions:
- NGF receptor expression is dynamically regulated throughout the cell cycle.
- Differential TrkA and p75(NTR) expression correlates with distinct NGF-mediated cellular responses.
- This study provides a framework for understanding NGF signal transduction mechanisms.