title: Signal propagation of the MAPK cascade in Xenopus oocytes: role of bistability and ultrasensitivity for a mixed problem.
abstract: The MAPK signaling cascade is nowadays understood as a network module highly conserved across species. Its main function is to transfer a signal arriving at the plasma membrane to the cellular interior. Current understanding of 'how' this is achieved involves the notions of ultrasensitivity and bistability which relate to the nonlinear dynamics of the biochemical network, ignoring spatial aspects. Much less, indeed, is so far known about the propagation of the signal through the cytoplasm. In this work we formulate, starting from a Michaelis-Menten model for the MAPK cascade in Xenopus oocytes, a reaction-diffusion model of the cascade. We study this model in one space dimension. Basing ourselves on previous general results on reaction diffusion models, we particularly study for our model the conditions for signal propagation. We show that the existence of a propagating front depends sensitively on the initial and boundary conditions at the plasma membrane. Possible biological consequences of this finding are discussed.
authors.affiliation: Institut de Recherche Interdisciplinaire, CNRS USR 3078, Parc de la Haute Borne, 50 avenue de Halley, BP 70478, 59658 Villeneuve d'Ascq Cedex, France. ralf.blossey@iri.univ-lille1.fr
authors.forename: Ralf
authors.initials: R
authors.lastname: Blossey
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Bodart
authors.forename: Anne
authors.initials: A
authors.lastname: Devys
authors.forename: Thierry
authors.initials: T
authors.lastname: Goudon
authors.forename: Pauline
authors.initials: P
authors.lastname: Lafitte
mesh_terms: D000818:Animals; D005260:Female; D007700:Kinetics; D020935:MAP Kinase Signaling System; D008954:Models, Biological; D017711:Nonlinear Dynamics; D009865:Oocytes / Q000201:enzymology*; D014981:Xenopus