Abstract B1-30: Receptor-level feedback mechanisms distinguish frequency- and amplitude-modulated ERK activation

Abstract

Abstract Receptor tyrosine kinases transduce signals through ERK and drive distinct cellular behaviors, but it is not clear how dynamic patterns of ERK activity are generated. To approach this question quantitatively, we have generated an epithelial cell line expressing a tunable version of the canonical nerve growth factor (NGF) receptor TrkA. Upon NGF stimulation, we visualized the dynamics of ERK activity in live cells using an improved fluorescent reporter for ERK activity, EKAR3. Examination of the NGF receptor pathway in isolation revealed that stimulation with NGF promotes a prolonged ERK activity pulse that is amplitude-modulated by the concentration of the stimulus, in contrast to the frequency modulation observed in the epidermal growth factor (EGF)-RAS-ERK pathway. This result implies that the primary determinants of ERK kinetics are the unique set of signaling proteins recruited to the activating receptor. To dissect the context in which ERK is activated in respect to parallel signaling pathways, we have engineered mutant NGF receptors that cannot be phosphorylated at one or more of the three adaptor binding sites and characterized how each signaling pathway contributes to the pattern of dynamic ERK activity. Furthermore, because our NGF receptor expression system allows the tunable and quantifiable expression of receptor levels, we have evaluated the effect of receptor number on ERK kinetics in single cells. Our findings indicate that the dynamics of ERK activity are in fact decided at the receptor-level and may explain how different receptor tyrosine kinase profiles in cancer cells modulate distinct patterns of ERK activity. Citation Format: Breanne Sparta, Michael Pargett, Kevin Distor, Marta Minguet, John G. Albeck. Receptor-level feedback mechanisms distinguish frequency- and amplitude-modulated ERK activation. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B1-30.