On July 7, Taylor Schaffner successfully defended the thesis “Plasma Membrane-Embedded Post-Translational Modification Networks Can Drive Self-Organized Criticality in Lipid Composition” (advisor: Ben Machta).
Schaffner explained, “Many post-translational modification networks take place in the fluid yet structured plasma membrane. Lipid domains, sometimes termed rafts, have been implicated in the functioning of various membrane-bound signaling processes. I developed a model and a Monte Carlo simulation framework to investigate how changes in the domain size that arise from perturbations to the membrane phase transition can lead to changes in the rate of interactions among components, leading to altered outcomes. For simple reaction networks, I show that the activity can be highly sensitive to the thermodynamic parameters of the membrane phase transition, especially near the critical point. Experimental measurements of two otherwise dissimilar systems, zebrafish cells and yeast vacuoles, exhibit near constant gaps between growth temperature and membrane miscibility temperature, hinting at a potentially fundamental regulatory mechanism. Further expanding upon my model, I demonstrate how the sensitivity of interaction rates among membrane-bound proteins can be directed into a feedback mechanism to tune the membrane’s composition near to or within a fixed distance of a thermodynamic critical point.”
Regarding his future plans, Schaffner stated, “Currently my next position is being a stay-at-home dad to my 8 month old son, Bernard. I will be providing naptime stories, such as Eric Carle’s Brown Bear, Brown Bear, What Do You See?, and high-chair meals, including but not limited to fresh peach slices and cheerios.”
Thesis Committee: Benjamin Machta (advisor), Simon Mochrie, Alison Sweeney, Sarah Veatch (University of Michigan), Isabella Graf (EMBL Heidelberg)