Kamioka, Y., Yasuda, S., Fujita, Y., Aoki, K., & Matsuda, M.


From the Department of Pathology and Biology of Diseases, Graduate School of Medicine, Laboratory of Bio-imaging and Cell Signalling, Graduate School of Bio-studies, and Innovative Techno-Hub for Integrated Medical Bio-Imaging, Kyoto University, Kyoto 606-8501 and Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan.




EGF-induced activation of ERK has been extensively studied by both experimental and theoretical approaches. Here, we used a simulation model based mostly on experimentally determined parameters to study the ERK-mediated negative feedback regulation of the Ras guanine nucleotide exchange factor, son of sevenless (SOS). Because SOS1 is phosphorylated at multiple serine residues upon stimulation, we evaluated the role of the multiplicity by building two simulation models, which we termed the decisive and cooperative phosphorylation models. The two models were constrained by the duration of Ras activation and basal phosphorylation level of SOS1. Possible solutions were found only in the decisive model wherein at least three, and probably more than four, phosphorylation sites decisively suppress the SOS activity. Thus, the combination of experimental approaches and the model analysis has suggested an unexpected role of multiple phosphorylations of SOS1 in the negative regulation.


… “with a light-emitting diode light source PreciseExcite (CoolLED, Hampshire, UK)”…

Product Associated Features

pE-100: A range of compact, simple-to-use, single wavelength illumination systems for screening fluorescence.

Product Type



The Journal of Biological Chemistry

Year of Publication


Country of Publication