title: Identification of nucleocytoplasmic cycling as a remote sensor in cellular signaling by databased modeling.
abstract: Considerable progress has been made in identifying the molecular composition of complex signaling networks controlling cell proliferation, differentiation, and survival. However, to discover general building principles and predict the dynamic behavior of signaling networks, it is necessary to develop quantitative models based on experimental observations. Here we report a mathematical model of the core module of the Janus family of kinases (JAK)-signal transducer and activator of transcription (STAT) signaling pathway based on time-resolved measurements of receptor and STAT5 phosphorylation. Applying the fitted model, we can determine the quantitative behavior of STAT5 populations not accessible to experimental measurement. By in silico investigations, we identify the parameters of nuclear shuttling as the most sensitive to perturbations and verify experimentally the model prediction that inhibition of nuclear export results in a reduced transcriptional yield. The model reveals that STAT5 undergoes rapid nucleocytoplasmic cycles, continuously coupling receptor activation and target gene transcription, thereby forming a remote sensor between nucleus and receptor. Thus, dynamic modeling of signaling pathways can promote functional understanding at the systems level.
authors.affiliation: Max-Planck-Institut für Immunbiologie, Stübeweg 51, D-79108 Freiburg, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Swameye
authors.forename: T G
authors.initials: TG
authors.lastname: Muller
authors.forename: J
authors.initials: J
authors.lastname: Timmer
authors.forename: O
authors.initials: O
authors.lastname: Sandra
authors.forename: U
authors.initials: U
authors.lastname: Klingmuller
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002470:Cell Survival; D003198:Computer Simulation; D003593:Cytoplasm / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D019992:Databases as Topic; D051379:Mice; D008894:Milk Proteins; D008954:Models, Biological; D008962:Models, Theoretical; D021381:Protein Transport; D050799:STAT5 Transcription Factor; D015398:Signal Transduction; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D008894:Milk Proteins; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; D001616:beta-Galactosidase