Theoretical modeling on mechanochemical feedbacks of cellular processes

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1. Membrane Trafficking: In this project, we investigated the functional role of the BAR and F-BAR domain proteins in yeast endocytosis. Our research showed that cooperation between robust actin polymerization, and F-BAR and BAR domain proteins, and synaptojanin, is important for membrane scission. Spatio-temporal and functional information together with our theoretical modeling suggest the following picture of endocytosis: F-BAR proteins stabilize the endocytic site, while actin assembly and BAR proteins cooperate for invagination and scission. This paper is currently under review for publication. 2. Kinetochore motility: Based on the histogram of the neighboring distance between kinetochore ring along microtubule, I contructed a statistical model to differentiate whether the rings can diffuse or not. Our research shows that kinetochore ring must be highly diffusive. The paper is currently in preparation for publication. 3. Asymmetric Furrow ingression during cytokinesis: We construct a minimal model on the contractility of actomyosin ring during cytokinesis. Our model proposes that the local geometry of the furrow site, such as the Gaussian curvature of the membrane, could promote the alignment process of actomyosin filament, which in turn governs the efficiency of the local contractility. As the more the local actomyosin filament contracts, the larger the local Gaussian curvature would become. We show that this mechanism can quantitatively account for all the three modes of actomyosin contractility, depending on the coupling strength of the positive feedback between the local membrane curvature and actomyosin contractility. More importantly, our experimental testing corroborates several predictions unique to our model, suggesting an emergent mechanism of curvature-mediated positive feedback for cytokinetic actomyosin contractility. Furthermore, the model demonstrate that asymmetric furrow ingression is energetically more efficient, thereby suggesting a real functional role of the asymmetry in cytokinetic ring contraction. This model is the first of its kinds. This paper is currently in preparation for publication.