Toward a comprehensive and quantitative understanding of intracellular microtubule organization

Abstract

Mol Syst Biol. 5: 251 The proposition that cell architecture is complex needs no justification. Moreover, intracellular organization changes with time in some cells yet persists in others. These properties are determined in part by microtubule cytoskeleton, which can provide both the consistency, e.g. by maintaining cell shape, and variability in response to changing intracellular tasks and environment. Microtubule behavior in vitro is described by four kinetic parameters (rates for growth and shrinkage and frequencies for the stochastic transitions between these states), and is also affected by the boundaries of a confined environment. In cells, there are multiple layers of additional regulation. Microtubule dynamics are affected globally by a large number of associated proteins, and locally through spatially distributed biochemical cues. Deciphering the interplay between microtubules, cell boundaries and their numerous regulators and components is therefore a daunting task. Two complementary articles published recently in Molecular Systems Biology provide a refreshing and inspiring example of how systematic, quantitative approaches that combine observations and mathematical modeling can help to break such complex problem into a set of logically appealing and manageable parts. Tischer et al (2009) and Foethke et al (2009) have analyzed the spatial regulation of microtubule dynamics and its role in intracellular organization, using the unicellular eukaryote Schizosaccharomyces pombe . Its cytoskeleton has been studied intensely, facilitated by this cell's simple shape (Hayles and Nurse, 2001). Several overlapping microtubule bundles attach to a centrally positioned …