부산대학교 도서관

Summary: ``Fragments of fish melanophore cells can form and centeraggregates of pigment granules by dynein-motor-driven transport alonga self-organized radial array of microtubules (MTs). We present aquantitative model that describes pigment aggregation and MT-asterself-organization and the subsequent centering of both structures. Themodel is based on the observations that MTs are immobile andtreadmill, while dynein-motor-covered granules have the ability tonucleate MTs. From assumptions based on experimental observations, wederive partial integro-differential equations describing the coupledgranule-MT interaction. We use scaling arguments and perturbationtheory to study the model in two limiting cases. The model analysisexplains the mechanism of aster self-organization as a positivefeedback loop between motor aggregation at the MT minus ends and MTnucleation by motors. Furthermore, the centering mechanism isexplained by the spontaneous nucleation of MTs throughout the cytosolwhich acts as a volume sensing tool. Numerical simulations lendadditional support to the analysis. The model sheds light on the role ofpolymer dynamics and polymer-motor interactions in cytoskeletalorganization.''