Amplitude vs Frequency modulation in cell signaling

SILVINA PONCE DAWSON

Conferencia; StatPhys28; 2023

Cells continuously sense their environment and respond accordingly. On many occasions, these responses involve changes in gene expression. To modulate this expression, stimulus strengths can be encoded in the amplitude or the frequency of Transcription Factor (TF) nuclear fractions. In this talk I will show the results of analyzing the information transmission capabilities of both modulation modes. A first comparison, from TF nuclear fraction to mRNA production, shows that the main difference between both modes is due to their different sensitivity to changes in the parameters characterizing transcription. We could find promoters that were selectively activated by TF pulses but could not find this selectivity for the prolonged nuclear TF accumulation that characterizes amplitude modulation. Due to its higher sensitivity, frequency modulation is then better suited than amplitude codification for signal identification without requiring other mediators of the transduction. Including the encoding step from the external stimulus to the TF nuclear fraction we found that both modes differ in the way they “map” the environment. While amplitude modulation works well for external stimuli around a pre-defined stimulus strength, frequency encoding displays scale-free characteristics with information transmission capabilities that improve with stimulus strengths, as long as the frequency remains below the maximum allowed one.