RECEPTOR-DEPENDENT SENSITIVITY OF NF-κB TO LOW PHYSIOLOGICAL LEVEL

In the NF kappa B signaling pathway, cells respond to different concentrations of the TNF alpha signal by means of NF kappa B transcription factors. Previous studies showed that most cells are activated under high-dose stimulations and NF kappa B activation results in oscillations in nuclear NF kappa B abundance. Here, by analyzing sensitivity gain for the response of the nuclear NF kappa B to the number of cell-surface receptors under low-dose stimulations, we show that changes in the receptor number can give rise to significant changes in the nonsaturation part of the dose-response curve, where the receptor activation rates are very sensitive to stimulations. In addition, the number of the activated receptors tends to increase in a large range of stimulation dose and can significantly influence the expression of the downstream genes. These results imply that the number of cell-surface receptors plays a role of information encoding like frequency or amplitude encoding described in previous studies.