| Abstract | Recent experimental analysis of cytoskeleton regulation, membrane trafficking and other manifestations of membrane dynamics demonstrated that small GTPases of Ras superfamily play a fundamental role in these phenomena. However it remains unclear what makes small GTPases such a ubiquitous and almost indispensable element of the underlying molecular networks. Recently we demonstrated (FEBS Lett., 582: 1437, 2008) that the biochemical processes in the emerging bud of yeast S. cerevisiae comprise a Turing-type mechanism. The roles of the prototypical activator and substrate are played by GTPase Cdc42 in its active and inactive states, respectively. Analysis of the instability that results in the formation of the pattern, a cluster of the activated Cdc42 that marks the position of the bud morphogenesis, was performed by a complementary set of analytical and computational approaches. Among these, a graph-theoretic method developed by Mincheva and Roussel for spatially-distributed systems (J. Chem. Phys., 125: 204102, 2006) has been particularly insightful as it allowed us to identify in the complete reaction mechanism a critical feedback loop that undermines the stability of the spatially homogeneous state. In this presentation we will further develop the concept of the GTPase-based mechanism of pattern formation and address issues of stability and uniqueness of such patterns in biologically realistic models of intracellular pattern formation. This is a joint work with Natasha S. Savage. |
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